Cocaine- and opiate-related fatal overdose in New York City, 1990–2000

  • Kyle T Bernstein1Email author,

    Affiliated with

    • Angela Bucciarelli2,

      Affiliated with

      • Tinka Markham Piper2,

        Affiliated with

        • Charles Gross3,

          Affiliated with

          • Ken Tardiff3 and

            Affiliated with

            • Sandro Galea4, 5

              Affiliated with

              BMC Public Health20077:31

              DOI: 10.1186/1471-2458-7-31

              Received: 24 July 2006

              Accepted: 09 March 2007

              Published: 09 March 2007

              Abstract

              Background

              In New York City (NYC), the annual mortality rate is higher for accidental drug overdoses than for homicides; cocaine and opiates are the drugs most frequently associated with drug overdose deaths. We assessed trends and correlates of cocaine- and opiate-related overdose deaths in NYC during 1990–2000.

              Methods

              Data were collected from the NYC Office of the Chief Medical Examiner (OCME) on all fatal drug overdoses involving cocaine and/or opiates that occurred between 1990–2000 (n = 8,774) and classified into three mutually exclusive groups (cocaine only; opiates-only; cocaine and opiates). Risk factors for accidental overdose were examined in the three groups and compared using multinomial logistic regression.

              Results

              Overall, among decedents ages 15–64, 2,392 (27.3%) were attributed to cocaine only and 2,825 (32.2%) were attributed to opiates-only. During the interval studied, the percentage of drug overdose deaths attributed to cocaine only fell from 29.2% to 23.6% while the percentage of overdose deaths attributed to opiates-only rose from 30.6% to 40.1%. Compared to New Yorkers who fatally overdosed from opiates-only, fatal overdose attributed to cocaine-only was associated with being male (OR = 0.71, 95% CI 0.62–0.82), Black (OR = 4.73, 95% CI 4.08–5.49) or Hispanic (OR = 1.51, 95% CI 1.29–1.76), an overdose outside of a residence or building (OR = 1.34, 95% CI 1.06–1.68), having alcohol detected at autopsy (OR = 0.50, 95% CI 0.44–0.56) and older age (55–64) (OR = 2.53 95% CI 1.70–3.75)).

              Conclusion

              As interventions to prevent fatal overdose become more targeted and drug specific, understanding the different populations at risk for different drug-related overdoses will become more critical.

              Background

              Illegal drug users experience mortality rates greater than those among the general population[1]. In the United States and Europe, mortality among drug users has been estimated to be at least nearly seven times that of the general population[25]. While the causes of mortality among drug using populations are varied and include trauma [6] and HIV/AIDS[7], overdose is an important contributor to mortality in this group [810]. In 2003, non-medically related drug toxicity was the tenth leading cause of mortality in New York City (NYC) [11].

              The overdose experiences of heroin users have been extensively studied [1216]. Furthermore, the development of effective interventions to reduce accidental opiate overdose death, such as the provision of naloxone and the creation of safe injecting spaces have also been described [1719]. Several review articles have been published synthesizing what we know about opiate overdose and its related mortality [2022]. However, a number of studies have shown that multi-drug use contributes dramatically to overdose death [15, 23, 24], and in several cities, cocaine is suspected to be a considerable contributor to accidental overdose mortality[9].

              While cocaine overdose is prevalent, there is a paucity of research that has examined the relative contribution of cocaine to overdose mortality. One of the few studies that examined fatal cocaine overdoses found that the route of administration for over 85% of decedents was injection, over half of the deaths occurred during a weekend and 41% of deaths occurred in the presence of others [25]. Therefore, although cocaine is probably an important contributor to overdose deaths in many urban areas[26], there is little research that has systematically explored the characteristics of decedents whose death is attributed to cocaine overdose[9].

              In NYC, previous studies have documented the importance of polydrug overdose to overall overdoses [9] and racial/ethnic disparities in overdose fatalities [10]. However, there have been no papers of which we are aware that have studied the factors associated with cocaine vs. opiate-related overdoses in NYC or elsewhere. While the importance of polydrug overdose cannot be understated, as interventions for the prevention of fatal overdose become more targeted, such as naloxone for opiate overdoses [17, 19, 22, 2729], a clearer understanding of the importance of opiate and cocaine fatal overdose as distinct events increase. In this study, we examined all accidental overdose deaths in NYC between 1990 and 2000 to characterize differences in cocaine- and opiate-related drug overdoses. In NYC, mortality related to drug overdose is of substantial public health concern [30]. Therefore, the purpose of this study was to explore the epidemiologic correlates of cocaine- and opiate only related overdose. Furthermore, we sought to examine whether these correlates were different between those decedents who fatally overdosed with both cocaine and opiates, cocaine alone, and opiates alone. Understanding these epidemiologic differences may prove critical in the development of successful, innovative interventions and prevention messages that can reduce overdose-related mortality.

              Methods

              Study Design

              All cases of fatal accidental drug overdose occurring in adults aged 15–64 years in NYC between 1990 and 2000 were identified through manual review of medical files at the Office of the Chief Medical Examiner of NYC (OCME).

              Study Population and Protocol

              The OCME is responsible for assessing all deaths of persons believed to have died in an unnatural manner in NYC. Therefore, all overdose deaths in NYC would have been reviewed by the OCME and included in this chart abstraction.

              The OCME investigators use the decedent's medical history, the circumstances and environment of the fatality, autopsy findings, and laboratory data in attributing cause of death and other criteria to each case reviewed. Deaths determined to be due to either suicide or homicide are not considered accidents by the OCME and hence are not included in this analysis. Data regarding age, gender, race/ethnicity, and residence were collected for all decedents from OCME files.

              Rate of autopsy vary by manner of death. Between 1990 and 2000 approximately 80% of accidents were autopsied. All autopsied cases undergo toxicological screenings. Blood and urine samples were obtained at autopsy and stored at 4°C until they were assayed. Opiates refer to entire class of opiates (methadone, morphine, etc) and not just heroin. Further details on these data collection and toxicological methods have been presented elsewhere[31].

              Data Analysis

              Analyses were conducted for all accidental overdose deaths involving cocaine and/or opiates. Between 1990 and 2000, 375 overdose deaths were identified that involved neither cocaine nor opiates; these were excluded from the analysis. We first described characteristics of all fatal overdoses in NYC between 1990 and 2000, including age, race/ethnicity, and gender of the decedents as well as drug and alcohol toxicities. We limited these analyses to all accidental drug overdose decedents aged 15–64 years old. Younger (<15) and older (65+) decedents were excluded from this analysis because of the potentially different drug use patterns and practices in these groups. In order to assess the epidemiology of opiate-related and cocaine-related overdose deaths we categorized decedents into three mutually exclusive categories: (a) overdose deaths in which cocaine (not in the presence of opiates) was the cause of death; these are referred to as "cocaine only" overdose deaths in the rest of the paper although we note that other drugs (except opiates) may also have been contributors of cause of death; and (b) overdose deaths in which opiates (without the presence of cocaine) were the cause of death; these are referred to as "opiate only" overdose deaths; (c) and overdose deaths in which both cocaine and opiates were the cause of death; these are referred to as "cocaine and opiate" overdose deaths. Deaths in which neither cocaine nor opiates were the cause of death were eliminated from the analysis. Decedents were categorized with respect only to cocaine and opiate presence at autopsy; other drug involvement was noted but did not impact on the above categorizations. For example, a decedent who had cocaine, opiates, and methamphetamines noted at autopsy, would be classified as cocaine and opiate overdose death; a decedent with cocaine and methamphetamines found at autopsy would be considered a cocaine only overdose death. One objective of this analysis was to determine if the epidemiologic characteristics of these three groups differed.

              We calculated the total number and proportion of overdose deaths attributed to cocaine and opiates in NYC from 1990 through 2000. χ2 statistics were used to examine trends in the number and proportion of cocaine excluding opiate and heroin-only induced overdose deaths. We described relevant characteristics of all accidental drug overdose deaths. Characteristics of interest included sex, race/ethnicity, age, borough of death, year of death, the toxicological presence of cannabis or alcohol, and the time and location of death. χ2 statistics were used to assess bivariate associations between decedent characteristics of interest and the likelihood of cocaine only, opiate only, and cocaine and opiate induced overdose deaths.

              The objective of this analysis was to examine differences between the three groups of decedents (cocaine only, opiate only, and cocaine and opiate). This was explored through two types of multivariate modeling. First, all covariates that were statistically significant at the p ≤ 0.05 level were included in multivariate logistic regression models. Additionally, a multinomial logistic regression model was performed to compare and contrast demographic and socio-economic predictors of cocaine-only and cocaine and opiate overdose with opiate-only overdose used as the referent category [32, 33].

              Results

              From 1990 through 2000, the OCME reported 8,774 fatal overdose deaths among New Yorkers aged 15–64 involving cocaine and/or opiates. Characteristics of total overdose, cocaine only overdose and opiate only overdose decedents in NYC are shown in Table 1. Among all overdose deaths during the study period, 2,392 (27.3%) were attributed to cocaine only and 2,825 (32.2%) were attributed to opiate only overdose.
              Table 1

              Bivariate associations of cocaine only, opiate only, and both cocaine and opiate overdose deaths among all accidental drug overdose decedents ages 15–64, New York City, 1990–2000*

               

              Total

              Cocaine only overdose deaths

              Opiate only overdose deaths

              Opiate and cocaine overdose deaths

              Characteristics

              N

              %

              N

              %

              p-value

              N

              %

              p-value

              N

              %

              p-value

              Total

              8774

              100.0

              2392

              27.3

              ---

              2825

              32.2

              ---

              3557

              40.5

              ---

              Sex

                         

                 Female

              1807

              20.6

              630

              34.9

              <0.001

              478

              26.5

              <0.001

              699

              38.7

              0.071

                 Male

              6967

              79.4

              1762

              25.3

               

              2347

              33.7

               

              2858

              41.0

               

              Race/ethnicity

                         

                 White

              2948

              33.6

              486

              16.5

              <0.001

              1242

              42.1

              <0.001

              1220

              41.4

              <0.001

                 Black

              3234

              36.9

              1348

              41.7

               

              671

              20.7

               

              1215

              37.6

               

                 Hispanic

              2592

              29.5

              558

              21.5

               

              912

              35.2

               

              1122

              43.3

               

              Age

                         

                 15–24

              419

              4.8

              70

              16.7

              <0.001

              170

              40.6

              <0.001

              179

              42.7

              <0.001

                 25–34

              2369

              27.0

              573

              24.2

               

              704

              29.7

               

              1092

              46.1

               

                 35–44

              3788

              43.2

              977

              25.8

               

              1242

              32.8

               

              1569

              41.4

               

                 45–54

              1834

              20.9

              602

              32.8

               

              609

              33.2

               

              623

              34.0

               

                 55–64

              364

              4.1

              170

              46.7

               

              100

              27.5

               

              94

              25.8

               

              Borough of death

                         

                 Manhattan

              2798

              32.0

              769

              27.5

              0.085

              783

              28.0

              <0.001

              1246

              44.5

              <0.001

                 Bronx

              2110

              24.1

              579

              27.4

               

              641

              30.4

               

              890

              42.2

               

                 Brooklyn

              2391

              27.3

              684

              28.6

               

              850

              35.5

               

              857

              35.8

               

                 Queens

              1273

              14.6

              311

              24.4

               

              469

              36.8

               

              493

              38.7

               

                 Staten Island

              176

              2.0

              49

              27.8

               

              82

              46.6

               

              71

              40.3

               

              Cannabis detected

                         

                 no

              8076

              92.0

              2248

              27.8

              <0.001

              2602

              32.2

              0.880

              3226

              39.9

              <0.001

                 yes

              698

              8.0

              144

              20.6

               

              223

              31.9

               

              331

              47.4

               

              Alcohol detected

                         

                 no

              5070

              57.8

              1663

              32.8

              <0.001

              1460

              28.8

              <0.001

              1947

              38.4

              <0.001

                 yes

              3704

              42.2

              729

              0.2

               

              1365

              36.9

               

              1610

              43.5

               

              Place of OD episode

                         

                 Other inside

              1122

              13.4

              257

              22.9

              <0.001

              363

              32.4

              0.002

              502

              44.7

              0.015

                 Residence

              6359

              75.7

              1697

              26.7

               

              2109

              33.2

               

              2553

              40.1

               

                 Outside

              918

              10.9

              291

              31.7

               

              250

              27.2

               

              377

              41.1

               

              Day of the week

                         

                 Monday-Thursday

              4647

              53.0

              1306

              28.1

              0.061

              1484

              31.9

              0.586

              1857

              40.0

              0.240

                 Friday-Sunday

              4127

              47.0

              1086

              26.3

               

              1341

              32.5

               

              1700

              41.2

               

              Year of death

                         

                 1990

              506

              5.8

              148

              29.2

              <0.001

              155

              30.6

              <0.001

              203

              40.1

              <0.001

                 1991

              708

              8.1

              247

              34.9

               

              184

              26.0

               

              277

              39.1

               

                 1992

              772

              8.8

              233

              30.2

               

              210

              27.2

               

              329

              42.6

               

                 1993

              1014

              11.6

              241

              23.8

               

              288

              28.4

               

              485

              47.8

               

                 1994

              994

              11.3

              283

              28.5

               

              266

              26.8

               

              445

              44.8

               

                 1995

              979

              11.2

              231

              23.6

               

              317

              32.4

               

              431

              44.0

               

                 1996

              852

              9.7

              250

              29.3

               

              290

              34.0

               

              312

              36.6

               

                 1997

              806

              9.2

              219

              27.2

               

              314

              39.0

               

              273

              33.9

               

                 1998

              737

              8.4

              193

              26.2

               

              251

              34.1

               

              293

              39.8

               

                 1999

              651

              7.4

              169

              26.0

               

              247

              37.9

               

              235

              36.1

               

                 2000

              755

              8.6

              178

              23.6

               

              303

              40.1

               

              274

              36.3

               

              *analysis restricted to decedents with opiates-only, cocaine only, and both opiates and cocaine detected

              Of the 8,774 fatal overdoses involving cocaine and/or opiates that occurred in NYC from 1990 to 2000, 79.4% were male, 33.6% were White, 36.9% were Black, and 29.5% were Hispanic. Nearly 75% of the decedents were younger than 45 years old at the time of death. Among the five boroughs of NYC, Manhattan had the largest proportion of accidental overdose deaths with 32.0% occurring in that borough; 27.3% of the total overdose fatalities occurred in Brooklyn, 24.1% in the Bronx, and smaller proportions in Queens (14.6%) and Staten Island (2.0%). While cannabis was detected in only 8.0% of the decedents at the time of death, alcohol was found in almost half (42.2%) of fatal overdoses. Most accidental overdose deaths occurred in a residence (75.7%). Almost one half of all overdose deaths occurred during a weekend (47.0%).

              The total number of accidental overdose deaths in NYC among 15–64 year olds related to cocaine and/or opiates increased from 1990 to 1993, plateaued, and then exhibited a steady decline until 1999 (Figure 1). A slight increase in the total fatal overdoses in this population was seen in 2000. While the number of cocaine only overdose deaths remained relatively constant from 1990–2000 (χ2 test for trend, p = 0.18), opiate only deaths saw a small, but steady increase during the same time period (χ2 test for trend, p = 0.10).
              http://static-content.springer.com/image/art%3A10.1186%2F1471-2458-7-31/MediaObjects/12889_2006_Article_642_Fig1_HTML.jpg
              Figure 1

              Overdose death attributed to only cocaine-only and opiate only among 15–64 year olds in NYC, 1990–2000 (N = 8,774). Cocaine only overdose deaths were decedents in which cocaine (not in the presence of opiates) was the cause of death; other drugs (except opiates) may also have been contributors of cause of death; Opiate only overdose deaths were decedents in which opiates (without the presence of cocaine) were the cause of death; other drugs (except cocaine) may also have been contributors of cause of death. Cocaine and opiate overdose deaths refers to overdose deaths in which both cocaine and opiates were the cause of death; other drugs may also have been contributors of cause of death.

              Figure 2 shows the trends in the proportion of total accidental overdose deaths that involved cocaine and/or opiates. While the absolute number of cocaine only fatal overdoses remains constant from 1990–2000, the proportion of overdoses attributed to cocaine-only declined during the 11-year period from 29.2% to 23.6% (χ2 test for trend, p = 0.07). Over the same period, the proportion of opiate only fatal overdoses rose from 30.6% in 1990 to 40.1% in 2000 (χ2 test for trend, p=<0.001).
              http://static-content.springer.com/image/art%3A10.1186%2F1471-2458-7-31/MediaObjects/12889_2006_Article_642_Fig2_HTML.jpg
              Figure 2

              Percentage of drug overdose death attributed to cocaine only and opiates-only among 15–64 year olds in NYC, 1990–2000 (N = 8,774). Cocaine only overdose deaths were decedents in which cocaine (not in the presence of opiates) was the cause of death; other drugs (except opiates) may also have been contributors of cause of death; Opiate only overdose deaths were decedents in which opiates (without the presence of cocaine) were the cause of death; other drugs (except cocaine) may also have been contributors of cause of death. Cocaine and opiate overdose deaths refers to overdose deaths in which both cocaine and opiates were the cause of death; other drugs may also have been contributors of cause of death.

              The descriptive characteristics of the three groups of decedents are shown in Table 1. Among women overdose decedents, 34.9% were classified as cocaine-only compared to 25.3% among men with a fatal overdose. This trend was reversed for opiate-only and cocaine and opiate overdose deaths. Among Black overdose decedents 41.7% were cocaine only, 20.7% opiate only, and 37.6% cocaine and opiate fatal overdoses. For Whites who fatally overdosed, the trend is different, with the largest proportion categorized as opiate (42.1%); the largest proportion of Hispanic decedents was cocaine and opiate overdose deaths (43.3%). A dose response was seen with respect to age with likelihood of cocaine only overdose among all overdose deaths, increasing with age (p < 0.001). Borough of death was associated with all three categories, with cocaine only and opiate only overdose fatalities occurring in the largest proportion for decedents residing in all boroughs except Staten Island. The absence of either cannabis (27.8% versus 20.6% for cannabis detected) or alcohol (32.8% versus 0.2% for alcohol detected) was associated with an increased likelihood of a cocaine only overdose (p < 0.001) among those fatally overdosing in NYC. All three groups had associations with location of overdose.

              The results of multivariate logistic regression models for the three categories of overdose decedents are shown in Table 2. The first model compared those with a cocaine only overdose death to those with a fatal overdose in the two other categories. Decedent males were less likely to experience a cocaine only overdose than females (adjusted OR = 0.77, 95% CI 0.68–0.87). Furthermore, both Black (adjusted OR = 3.23, 95% CI 2.85–3.67) and Hispanic (adjusted OR = 1.37, 95% CI 1.19–1.58) overdose fatalities were more likely to be from cocaine only, compared to Whites. Decedents at older ages were more likely to have fatally overdosed from cocaine only than from some other drug(s). No associations were found between borough of death, cannabis detection, or year of death and cocaine only overdose. However, a negative association was found between alcohol presence at autopsy and cocaine only fatal overdose.
              Table 2

              Multivariate logistic regression models of cocaine only and opiate only and both cocaine and opiate overdose deaths among all accidental drug decedents ages 15–64, New York City, 1990–2000*

               

              Cocaine only overdose deaths

              Opiate only overdose deaths

              Cocaine and opiate overdose deaths

               

              Adjusted

              Adjusted

              Adjusted

              Characteristics

              OR

              95 CI

              OR

              95 CI

              OR

              95 CI

              Sex

                    

                 Female

              REF

              ---

              REF

              ---

              REF

              ---

                 Male

              0.77

              0.68–0.87

              1.22

              1.08–1.38

              1.05

              0.94–1.17

              Race/ethnicity

                    

                 White

              REF

              ---

              REF

              ---

              REF

              ---

                 Black

              3.23

              2.85–3.67

              0.36

              0.32–0.41

              0.94

              0.84–1.04

                 Hispanic

              1.37

              1.19–1.58

              0.78

              0.69–0.87

              1.06

              0.94–1.18

              Age

                    

                 15–24

              REF

              ---

              REF

              ---

              REF

              ---

                 25–34

              1.41

              1.07–1.88

              0.68

              0.54–0.84

              1.15

              0.93–1.43

                 35–44

              1.35

              1.02–1.78

              0.86

              0.69–1.06

              0.98

              0.80–1.21

                 45–54

              1.81

              1.36–2.41

              0.92

              0.73–1.15

              0.73

              0.58–0.91

                 55–64

              2.95

              2.09–4.17

              0.80

              0.58–1.09

              0.49

              0.36–0.67

              Borough of death

                    

                 Manhattan

              REF

              ---

              REF

              ---

              REF

              ---

                 Bronx

              1.02

              0.89–1.17

              1.13

              0.99–1.28

              0.90

              0.80–1.02

                 Brooklyn

              1.04

              0.92–1.19

              1.46

              1.29–1.65

              0.70

              0.63–0.79

                 Queens

              1.05

              0.89–1.24

              1.34

              1.15–1.55

              0.75

              0.66–0.86

                 Staten Island

              1.28

              0.90–1.81

              1.30

              0.96–1.76

              0.67

              0.49–0.90

              Place of OD episode

                    

                 Other inside (not residence)

              REF

              ---

              REF

              ---

                

                 Residence

              0.96

              0.84–1.10

              1.09

              0.96–1.23

                

                 Outside

              1.27

              1.05–1.54

              0.86

              0.71–1.04

                

              Cannabis detected

                    

                 no

              REF

              ---

                

              REF

              ---

                 yes

              0.85

              0.69–1.03

                

              1.27

              1.08–1.49

              Alcohol detected

                    

                 no

              REF

              ---

              REF

              ---

              REF

              ---

                 yes

              0.53

              0.48–0.59

              1.39

              1.26–1.53

              1.20

              1.10–1.32

              Year of death

                    

                 1990

              REF

              ---

              REF

              ---

              REF

              ---

                 1991

              1.25

              0.96–1.62

              0.80

              0.62–1.04

              0.99

              0.78–1.25

                 1992

              1.12

              0.86–1.45

              0.77

              0.61–1.00

              1.12

              0.89–1.42

                 1993

              0.80

              0.62–1.03

              0.81

              0.64–1.03

              1.39

              1.12–1.73

                 1994

              0.98

              0.76–1.26

              0.76

              0.60–0.97

              1.27

              1.02–1.58

                 1995

              0.74

              0.58–0.96

              1.00

              0.79–1.27

              1.23

              0.99–1.53

                 1996

              1.01

              0.78–1.30

              1.05

              0.83–1.35

              0.95

              0.75–1.19

                 1997

              0.90

              0.69–1.17

              1.34

              1.05–1.71

              0.82

              0.65–1.04

                 1998

              0.85

              0.65–1.11

              1.03

              0.81–1.33

              1.10

              0.87–1.39

                 1999

              0.85

              0.65–1.12

              1.21

              0.94–1.57

              0.94

              0.73–1.20

                 2000

              0.74

              0.57–0.97

              1.31

              1.03–1.68

              0.96

              0.76–1.22

              *analysis restricted to decedents with opiates-only, cocaine only, and both opiates and cocaine detected

              The second model shown in Table 2 examined opiate only fatal overdoses compared to the other two groups. Here, males were more likely to experience an opiate only than any other drug combination (adjusted OR = 1.22, 95% CI 1.08–1.38). Contrary to what was found with respect to cocaine only overdose fatalities, for drug decedent New Yorkers, Whites were more likely to have an opiate only than Hispanics or Blacks. After adjustment for other covariates, the negative association with age all but disappeared. When borough of death was examined (borough of Manhattan used as the referent category), those New Yorkers fatally overdosing in Brooklyn (adjusted OR = 1.46, 95% CI 1.29–1.65) or Queens (adjusted OR = 1.34, 95% CI 1.15–1.55), decedents were more likely to have had an opiate only overdose. Alcohol detection at autopsy was associated with a nearly 40% increase in the likelihood that a New Yorker fatally overdosed on opiates-only, compared to other fatal drug combinations.

              No gender or race associations were found when cocaine and opiate fatal drug overdoses were modeled. Decedents over 45 years old were less likely to have overdosed on a combination of cocaine and opiates. When compared to Manhattan, decedent in Brooklyn, Queens, or Staten Island were less likely to have had an overdose attributed to cocaine and opiates. Both cannabis and alcohol detection was associated with an increased likelihood of overdose death from cocaine and opiates, compared to overdose death attributed to other drug combinations.

              Table 3 shows the results of the single multinomial regression model in which cocaine only is directly compared to opiate only overdose deaths. Male decedents were less likely to have overdosed on cocaine only than opiates-only. Additionally, Blacks who fatally overdosed were nearly five times more likely to have done so from cocaine only; Hispanics were 1.5 times more likely. Age at death greater than 24 was associated with an increased likelihood that the fatal overdose was attributed to cocaine only rather than opiates-only. Overdose death in Brooklyn was more likely a result of opiates-only than cocaine only. Fatal overdoses that occurred outside were more likely to have been attributed to cocaine only than opiates only. Alcohol detected at autopsy was half as likely among those who overdosed on cocaine only. There was no significant association observed for overdose deaths from cocaine only with respect to year of death.
              Table 3

              Multinomial logistic regression comparing cocaine only and both opiate and cocaine overdose compared to opiate only overdose deaths among decedents ages 15–64, New York City, 1990–2000*

               

              Cocaine only overdose deaths vs opiate only overdose deaths

              Opiate/cocaine overdose deaths vs opiate only overdose deaths

               

              Adjusted model

              Adjusted model

              Characteristics

              OR

              95 CI

              p-value

              OR

              95 CI

              p-value

              Sex

                    

                 Female

              REF

              ---

              ---

              REF

              ---

              ---

                 Male

              0.71

              0.62 – 0.82

              <0.0001

              0.88

              0.77 – 1.01

              0.0733

              Race/ethnicity

                    

                 White

              REF

              ---

              ---

              REF

              ---

              ---

                 Black

              4.73

              4.08 – 5.49

              <0.0001

              1.94

              1.71 – 2.21

              <0.0001

                 Hispanic

              1.51

              1.29 – 1.76

              <0.0001

              1.20

              1.06 – 1.36

              0.0035

              Age

                    

                 15–24

              REF

              ---

              ---

              REF

              ---

              ---

                 25–34

              1.74

              1.27 – 2.37

              0.0005

              1.41

              1.12 – 1.79

              0.0040

                 35–44

              1.43

              1.05 – 1.94

              0.0217

              1.11

              0.88 – 1.39

              0.3891

                 45–54

              1.69

              1.23 – 2.32

              0.0012

              0.88

              0.69 – 1.13

              0.3318

                 55–64

              2.53

              1.70 – 3.75

              <0.0001

              0.75

              0.52 – 1.08

              0.1254

              Borough of death

                    

                 Manhattan

              REF

              ---

              ---

              REF

              ---

              ---

                 Bronx

              0.93

              0.79 – 1.10

              0.3915

              0.87

              0.76 – 1.00

              0.0551

                 Brooklyn

              0.80

              0.68 – 0.93

              0.0033

              0.63

              0.55 – 0.72

              <0.0001

                 Queens

              0.85

              0.71 – 1.03

              0.0934

              0.70

              0.60 – 0.82

              <0.0001

                 Staten Island

              1.01

              0.69 – 1.49

              0.9575

              0.66

              0.47 – 0.93

              0.0165

              Place of OD episode

                    

                 Other inside (not residence)

              REF

              ---

              ---

              REF

              ---

              ---

                 Residence

              0.92

              0.78 – 1.07

              0.2830

              0.93

              0.81 – 1.06

              0.2754

                 Outside

              1.34

              1.06 – 1.68

              0.0127

              1.08

              0.88 – 1.32

              0.4626

              Cannabis detected

                    

                 no

              REF

              ---

              ---

              REF

              ---

              ---

                 yes

              0.96

              0.77 – 1.21

              0.7590

              1.25

              1.04 – 1.50

              0.0161

              Alcohol detected

                    

                 no

              REF

              ---

              ---

              REF

              ---

              ---

                 yes

              0.50

              0.44 – 0.56

              <0.0001

              0.89

              0.80 – 0.98

              0.0221

              Year of death

                    

                 1990

              REF

              ---

              ---

              REF

              ---

              ---

                 1991

              1.37

              1.00 – 1.87

              0.0465

              1.17

              0.88 – 1.55

              0.2790

                 1992

              1.30

              0.95 – 1.77

              0.0963

              1.28

              0.97 – 1.68

              0.0831

                 1993

              0.98

              0.72 – 1.31

              0.8726

              1.38

              1.06 – 1.78

              0.0157

                 1994

              1.19

              0.89 – 1.60

              0.2449

              1.38

              1.06 – 1.79

              0.0161

                 1995

              0.79

              0.59 – 1.07

              0.1281

              1.11

              0.86 – 1.44

              0.4269

                 1996

              0.97

              0.72 – 1.30

              0.8246

              0.93

              0.71 – 1.21

              0.5770

                 1997

              0.76

              0.56 – 1.03

              0.0727

              0.73

              0.56 – 0.95

              0.0210

                 1998

              0.86

              0.63 – 1.18

              0.3552

              1.03

              0.78 – 1.35

              0.8522

                 1999

              0.78

              0.57 – 1.07

              0.1178

              0.84

              0.64 – 1.11

              0.2271

                 2000

              0.66

              0.49 – 0.91

              0.0098

              0.81

              0.62 – 1.06

              0.1276

              *analysis restricted to decedents with opiates-only, cocaine only, and both opiates and cocaine detected

              While no gender association was observed from the multinomial regression model with respect to cocaine and opiate fatal overdose (Table 3), both Blacks and Hispanics who fatally overdosed were more likely to have the fatality attributed to cocaine and opiates than opiates-only. There was a weak trend towards older decedents being less likely to overdose on cocaine and opiates. Death in the boroughs of Brooklyn, Queens or Staten Island was inversely associated with a cocaine and opiates fatal overdose. Detection of alcohol at autopsy was negatively associated with cocaine and opiates overdose, while cannabis detection at autopsy showed a positive association.

              Discussion

              We examined all accidental drug overdose deaths involving cocaine and/or opiates that occurred in NYC between 1990 and 2000. While the absolute number of cocaine only overdose deaths remained relatively stable throughout the period, the number of opiate only fatal overdoses rose slightly. Of all overdose deaths during the study period, 27.3% were attributed to cocaine only and 32.2 to opiates-only. Decedents who had fatal cocaine only overdoses appear to differ from those who had opiate only overdoses. This suggests that those New Yorkers who die from accidental cocaine- or opiate only overdoses represent two distinct populations, requiring different interventions aimed at prevention.

              While the number of cocaine only overdoses was stable over the decade examined, cocaine only overdoses accounted for a quarter of total fatal overdoses. This number is considerably higher when polydrug overdoses involving both cocaine and opiates are included, underscoring the contribution of cocaine abuse to overdose deaths in NYC. Accidental fatal overdose is possible with even a relatively low concentration of cocaine [3436]. Furthermore, cocaine use is not restricted to injectors only. While less common than injecting users, non-injection cocaine users do experience overdoses [26]. Intranasal cocaine abuse among affluent, employed populations also has been associated with fatal overdoses [3739]. Although our dataset does not allow us to ascertain different modes of cocaine administration, the contribution of cocaine to overall overdose deaths is unmistakable and has clear implications for overdose prevention efforts that predominantly target opiate use only [17, 20, 40, 41].

              There were several important differences between cocaine only and opiate only decedent populations. In the multiple logistic regression models, female decedents were more likely to have a cocaine only overdose and male decedents an opiate only overdose. This finding is contrary to other studies [25, 42] and particularly interesting since it has been shown that males with a fatal cocaine overdose were more likely to have contributory coronary disease[25]. The higher risk of cocaine only overdose among women seen in our analysis may reflect unique characteristics of the drug economy and drug use patterns in the United States or in NYC and bears further study.

              Our results suggest that cocaine only and opiate only overdose decedents represent two substantially different population groups. For cocaine only overdose fatalities, minorities (Blacks and Hispanics) were at a significantly higher risk. These findings have been confirmed in previous analyses[10]. There were also geographic differences in the locations of cocaine only vs. opiate only deaths in NYC. Among overdose fatalities, being found to have an opiate only overdose death was associated with residence in Brooklyn or Queens. When cocaine only and opiate only fatal overdoses were examined in the multinomial regression model, only death in Brooklyn showed a significant association. To some degree, these disparities may reflect differences in drug use patterns among different racial/ethnic groups in certain boroughs of the city. Consistent with our observations, other studies have shown that in NYC, opiate use occurs largely among younger Whites [43] and that nationally, cocaine use was more likely among minorities than among Whites[44].

              The median age of both cocaine only and opiate only decedents was between 34–44. In the multinomial regression model, older age at fatal overdose was associated with a cocaine only fatal overdose. Furthermore, the data were suggestive of increasing likelihood of a cocaine only overdose with increasing age. While we do not have data on the age of initiation of cocaine use in this dataset, the finding of an increasing risk of overdose with increasing age may suggest either that newer users are less likely to experience a fatal overdose or that younger persons were more likely to use opiates than cocaine. It is also possible that pre-existing medical conditions, such as atherosclerosis and heart disease, which occur more commonly in older individuals[45], may be exacerbated by cocaine use, even in moderate doses.

              The location of the overdose episode was not associated with an opiate only-induced fatality. However, an overdose outside (compared to a non-residential indoor location) was positively associated with a cocaine only accidental overdose death. The lack of an association between location of overdose episode and opiate only death may be explained by the fact that many opiate users have experienced or witnessed an overdose[20] and may be more apt to intervene with either life-saving measures or contact of emergency personnel. This finding is particularly relevant as more interventions targeting opiate overdose are implemented [46].

              The presence of alcohol at autopsy was associated with an increased likelihood of an opiate only overdose, a finding that has been corroborated by others[12, 13, 22, 47]. The trend was reversed however with respect to cocaine only overdose death, with the presence of alcohol being less likely. No association was found for cannabis presence for either cocaine only and opiate only accidental overdose fatalities. This finding underscores the poly-use nature of substance abuse. While we examined cocaine without the use of opiates and opiates without the use of cocaine for the purposes of understanding differences between these two drugs as contributors to overdose, we note that polydrug use was the predominant contributor of overdose deaths in this dataset.

              In contrast to the findings of Darke et al [25] with respect to cocaine overdose death, we found no association with respect to overdose death occurring on the weekend versus a weekday for cocaine only or opiate only overdose death. This finding is consistent with the literature regarding heroin overdose[8, 14]. It has been suggested that this finding may indicate a largely unemployed population, who use drugs on a regular basis as opposed to more recreational weekend abusers [25]. No consistent trend was identified with respect to year of death. The difference between our observations and those of Darke et al. may reflect geographic differences in patterns of cocaine use between the US and Australia, specifically the rare use of crack cocaine in Australia[48].

              There are several limitations to this analysis. Determining the relative contribution of cocaine or opiates in the cause of death, when both drugs are ingested in concert is difficult since OCME determinations of cause of death are based on several factors, including (but not limited to) toxicology. The NYC OCME has standardized protocols for the classification of causes of death and all medical examiners were extensively trained. While likely small, variation among both medical examiners and among cases is possible, which may lead to misclassification of some of the data presented here. We present absolute numbers of overdose deaths and not rates in this analysis. Estimation of rates would require interpolation of denominator data. For example, to determine the rate of cocaine-only fatal overdoses would require an estimation of the total number of users of cocaine-only users in NYC. Data such as this is not readily accessible and likely would under-represent the number of true users. Thus, these data provide little information regarding the patterns of drug use, rather the patterns of fatal overdose. While we understand that drug use patterns vary by geography, age, and other factors, the objective of this analysis was to provide insight into the relative differences in overdose deaths from opiates and cocaine. Additionally, we have no information regarding the route of administration, dosage, or context of the opiates and cocaine. However, the fact that we do not have data regarding these factors should not obviate the findings we present here. Therefore, we present the absolute number of fatal overdose deaths, with the caveat that these data may not represent changes in the numbers of drug users in NYC.

              This analysis excluded overdose deaths determined to be suicides by the OCME as well as fatal overdoses among those under the age of 15 and older than 65 and fatal overdoses not involving cocaine and/or opiates. Overdoses resulting from suicide likely represent a different set of behavioral mechanisms than accidental overdoses. Here we examine the differences between the characteristics of those accidental overdoses attributed to different drug combinations with the intent of informing interventions to reduce morbidity and mortality. Therefore, the addition of intentional (suicide) overdoses would have diminished our ability to examine correlates of accidental overdose. Furthermore, it is likely that the drug use patterns of individuals under 15 and over 65 are qualitatively different from those between 15 and 65, therefore we excluded them from analysis. The results of this study may not be generalizable outside of NYC, where using patterns may be dramatically different.

              Conclusion

              This study is one of few that examine cocaine only fatal overdose and the only study we are aware of that describes the differences in decedents of opiate only and cocaine only overdose. Cocaine was an important contributor to accidental fatal overdose in NYC and was involved in nearly two-thirds of all decedents. Even though substantially more research has been published regarding opiate overdose than cocaine, we found that the proportion of overdose fatalities attributable to opiate only and cocaine only was similar throughout the decade. Additionally, these findings suggest that those who die from an opiate-only overdose are quite different from those who fatally overdose with cocaine only. The implications of these findings highlight the need to better understand the unique characteristics of different drug using populations, particularly in light of dynamic substance abuse epidemics[49]. Interventions designed to reduce overdose and its accompanying mortality that have proven successful in opiate-using populations may not work in populations of cocaine only users. Given the significant contribution of cocaine, both alone and in combination with other drugs to overdose mortality, a better understanding of the characteristics and risk factors for accidental fatality are critical for effective prevention.

              List of Abbreviations

              NYC: 

              New York City

              OCME: 

              Office of the Chief Medical Examiner

              OR: 

              Odds Ratio

              CI: 

              Confidence Interval

              Declarations

              Acknowledgements

              Funding Source: NIH DA06534 and DA017642

              Authors’ Affiliations

              (1)
              Department of Emergency Medicine, School of Medicine, New York University
              (2)
              Center for Urban Epidemiologic Studies, New York Academy of Medicine
              (3)
              Department of Psychiatry Weill Medical College, Cornell University
              (4)
              Department of Epidemiology, School of Public Health, University of Michigan
              (5)
              Department of Epidemiology, Columbia University Mailman School of Public Health

              References

              1. Neumark YD, Van Etten ML, Anthony JC: "Alcohol dependence" and death: survival analysis of the Baltimore ECA sample from 1981 to 1995. Subst Use Misuse 2000, 35: 533–549.View ArticlePubMed
              2. Joe GW, Simpson DD: Mortality rates among opioid addicts in a longitudinal study. Am J Public Health 1987, 77: 347–348.View ArticlePubMed
              3. Frischer M, Goldberg D, Rahman M, Berney L: Mortality and survival among a cohort of drug injectors in Glasgow, 1982–1994. Addiction 1997, 92: 419–427.PubMed
              4. Oppenheimer E, Tobutt C, Taylor C, Andrew T: Death and survival in a cohort of heroin addicts from London clinics: a 22-year follow-up study. Addiction 1994, 89: 1299–1308.View ArticlePubMed
              5. Perucci CA, Davoli M, Rapiti E, Abeni DD, Forastiere F: Mortality of intravenous drug users in Rome: a cohort study. Am J Public Health 1991, 81: 1307–1310.View ArticlePubMed
              6. Demetriades D, Gkiokas G, Velmahos GC, Brown C, Murray J, Noguchi T: Alcohol and illicit drugs in traumatic deaths: prevalence and association with type and severity of injuries. J Am Coll Surg 2004, 199: 687–692.View ArticlePubMed
              7. Smith DK, Gardner LI, Phelps R, Hamburger ME, Carpenter C, Klein RS, Rompalo A, Schuman P, Holmberg SD: Mortality rates and causes of death in a cohort of HIV-infected and uninfected women, 1993–1999. J Urban Health 2003, 80: 676–688.PubMed
              8. Bryant WK, Galea S, Tracy M, Markham PT, Tardiff KJ, Vlahov D: Overdose deaths attributed to methadone and heroin in New York City, 1990–1998. Addiction 2004, 99: 846–854.View ArticlePubMed
              9. Coffin PO, Galea S, Ahern J, Leon AC, Vlahov D, Tardiff K: Opiates, cocaine and alcohol combinations in accidental drug overdose deaths in New York City, 1990–98. Addiction 2003, 98: 739–747.View ArticlePubMed
              10. Galea S, Ahern J, Tardiff K, Leon A, Coffin PO, Derr K, Vlahov D: Racial/ethnic disparities in overdose mortality trends in New York City, 1990–1998. J Urban Health 2003, 80: 201–211.PubMed
              11. New York City Department of Health and Mental Hygiene: Summary of Vital Statistics 2003. 2004.
              12. Heroin overdose deaths--Multnomah County, Oregon, 1993–1999MMWR Morb Mortal Wkly Rep 2000, 49: 633–636.
              13. Unintentional opiate overdose deaths--King County, Washington, 1990–1999MMWR Morb Mortal Wkly Rep 2000, 49: 636–640.
              14. Darke S, Ross J, Zador D, Sunjic S: Heroin-related deaths in New South Wales, Australia, 1992–1996. Drug Alcohol Depend 2000, 60: 141–150.View ArticlePubMed
              15. McGregor C, Darke S, Ali R, Christie P: Experience of non-fatal overdose among heroin users in Adelaide, Australia: circumstances and risk perceptions. Addiction 1998, 93: 701–711.View ArticlePubMed
              16. Zador D, Sunjic S, Darke S: Heroin-related deaths in New South Wales, 1992: toxicological findings and circumstances. Med J Aust 1996, 164: 204–207.PubMed
              17. Darke S, Hall W: The distribution of naloxone to heroin users. Addiction 1997, 92: 1195–1199.View ArticlePubMed
              18. Lenton SR, Hargreaves KM: Should we conduct a trial of distributing naloxone to heroin users for peer administration to prevent fatal overdose? Med J Aust 2000, 173: 260–263.PubMed
              19. Strang J, Darke S, Hall W, Farrell M, Ali R: Heroin overdose: the case for take-home naloxone. Bmj 1996, 312: 1435–1436.PubMed
              20. Darke S, Hall W: Heroin overdose: research and evidence-based intervention. J Urban Health 2003, 80: 189–200.PubMed
              21. Darke S, Zador D: Fatal heroin 'overdose': a review. Addiction 1996, 91: 1765–1772.View ArticlePubMed
              22. Sporer KA: Acute heroin overdose. Ann Intern Med 1999, 130: 584–590.PubMed
              23. Ochoa KC, Hahn JA, Seal KH, Moss AR: Overdosing among young injection drug users in San Francisco. Addict Behav 2001, 26: 453–460.View ArticlePubMed
              24. Strang J, Griffiths P, Powis B, Fountain J, Williamson S: Which drugs cause overdose among opiate users? Study of personal and witnessed overdoses. Drug Alcohol Rev 1999, 18: 253–261.View Article
              25. Darke S, Kaye S, Duflou J: Cocaine-related fatalities in New South Wales, Australia 1993–2002. Drug Alcohol Depend 2005, 77: 107–114.View ArticlePubMed
              26. Kaye S, Darke S: Non-fatal cocaine overdose among injecting and non-injecting cocaine users in Sydney, Australia. Addiction 2004, 99: 1315–1322.View ArticlePubMed
              27. Coffin PO, Fuller C, Vadnai L, Blaney S, Galea S, Vlahov D: Preliminary evidence of health care provider support for naloxone prescription as overdose fatality prevention strategy in New York City. J Urban Health 2003, 80: 288–290.PubMed
              28. Galea S, Worthington N, Piper TM, Nandi VV, Curtis M, Rosenthal DM: Provision of naloxone to injection drug users as an overdose prevention strategy: early evidence from a pilot study in New York City. Addict Behav 2006, 31: 907–912.View ArticlePubMed
              29. Tracy M, Piper TM, Ompad D, Bucciarelli A, Coffin PO, Vlahov D, Galea S: Circumstances of witnessed drug overdose in New York City: implications for intervention. Drug Alcohol Depend 2005, 79: 181–190.View ArticlePubMed
              30. Substance Abuse and Mental Health Services Administration: Mortality from DAWN. Rockville, MD 2004., DAWN Series D-19:
              31. Tardiff K, Marzuk PM, Leon AC, Hirsch CS, Stajic M, Portera L, Hartwell N: Homicide in New York City. Cocaine use and firearms. Jama 1994, 272: 43–46.View ArticlePubMed
              32. Rothman KJ, Greenland S: Modern Epidemiology 2nd Edition Philadelphia, PA, Lippencott-Raven Publishers 1998.
              33. Altman DG: Practical Statistics for Medical Research London, Chapman and Hall 1991, 611.
              34. Karch SB: Karch's Pathology of Drug Abuse Boca Raton, FL., CRC Press 2002.
              35. Lange RA, Hillis LD: Cardiovascular complications of cocaine use. N Engl J Med 2001, 345: 351–358.View ArticlePubMed
              36. Platt JJ: Cocaine addiction. Theory, research, and treatment Cambridge, MA, Harvard Univeristy Press 1997.
              37. Goldfrank LR, Hoffman RS: The cardiovascular effects of cocaine. Ann Emerg Med 1991, 20: 165–175.View ArticlePubMed
              38. Jeffcoat AR, Perez-Reyes M, Hill JM, Sadler BM, Cook CE: Cocaine disposition in humans after intravenous injection, nasal insufflation (snorting), or smoking. Drug Metab Dispos 1989, 17: 153–159.PubMed
              39. Lange RA, Cigarroa RG, Flores ED, McBride W, Kim AS, Wells PJ, Bedotto JB, Danziger RS, Hillis LD: Potentiation of cocaine-induced coronary vasoconstriction by beta-adrenergic blockade. Ann Intern Med 1990, 112: 897–903.PubMed
              40. Hunt NG, Southwell M, G. S, Strang J: Preventing and curtailing drug use: a review of oppoutunities for developing and delivering "route transition interventions". Drug Alcohol Rev 1999, 18: 441–445.View Article
              41. Ronco C, Spuhler G, Coda P, Schopfer R: [Evaluation of street facilities I, II and III in Basel]. Soz Praventivmed 1996, 41 Suppl 1: S58-S68.View ArticlePubMed
              42. Tardiff K, Marzuk PM, Leon AC, Portera L, Hartwell N, Hirsch CS, Stajic M: Accidental fatal drug overdoses in New York City: 1990–1992. Am J Drug Alcohol Abuse 1996, 22: 135–146.View ArticlePubMed
              43. Spunt B: The current New York City heroin scene. Subst Use Misuse 2003, 38: 1539–1549.View ArticlePubMed
              44. Merline AC, O'Malley PM, Schulenberg JE, Bachman JG, Johnston LD: Substance use among adults 35 years of age: prevalence, adulthood predictors, and impact of adolescent substance use. Am J Public Health 2004, 94: 96–102.View ArticlePubMed
              45. Goldman L, Ausiello D: Textbook of Medicine Philadelphia, PA, Suanders 2004.
              46. Worthington N, Markham PT, Galea S, Rosenthal D: Opiate users' knowledge about overdose prevention and naloxone in New York City: a focus group study. Harm Reduct J 2006, 3: 19.PubMed
              47. Warner-Smith M, Darke S, Lynskey M, Hall W: Heroin overdose: causes and consequences. Addiction 2001, 96: 1113–1125.View ArticlePubMed
              48. Darke S, Kaye S, Topp L: Cocaine use in New South Wales, Australia, 1996–2000: 5 year monitoring of trends in price, purity, availability and use from the illicit drug reporting system. Drug Alcohol Depend 2002, 67: 81–88.View ArticlePubMed
              49. Paulozzi LJ, Budnitz DS, Xi Y: Increasing deaths from opioid analgesics in the United States. Pharmacoepidemiol Drug Saf 2006, 15: 618–627.View ArticlePubMed
              50. Pre-publication history

                1. The pre-publication history for this paper can be accessed here:http://​www.​biomedcentral.​com/​1471-2458/​7/​31/​prepub

              Copyright

              © Bernstein et al. 2007

              This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://​creativecommons.​org/​licenses/​by/​2.​0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.