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Table 4 Validation of diagnoses in the Swedish Inpatient Register by sensitivity

From: External review and validation of the Swedish national inpatient register

Diagnosis Proportion identified through the IPR (%) (sensitivity) Comment Main Author PubMed ID Year Gold Standard (Reference)
Cardiovascular disease
Myocardial Infarction (MI) 54/59 (91.5) Cross-sectional, 1-year retrospective study. ≥20 year-olds from Degerfors area. Elo [14] 19084244 2009 Data were obtained from IPR, hospital-based outpatient care and primary health care
Myocardial infarction 99/128 (77)   Merlo [63] 10870938 2000 Men born 1914
Myocardial infarction 113/144 (79)   Merlo [63] 10870938 2000 The Skaraborg Hypertension Study
Myocardial Infarction 3201/4148 (77.2) The researchers identified all MIs in Stockholm county in 1973 through the local IPR and the national Cause of Death Register (restricted to individuals living in Stockholm). Ahlbom [64] 721364 1978 Swedish Cause of Death Register
Myocardial infarction 4746/5832 (81.4) of MI cases in community registers were found in IPR or the Cause of Death Register. IPR and Cause of Death Register data from 1972-1981 for regions with IPR registers at the time. 81% of cases in community registers were found in IPR or Cause of Death Register. Meanwhile 85% of cases in IPR and the Cause of Death Register were found in Community registers (disregarding non-matching fatal cases). Hammar [65] 2066207 1991 Community registers with myocardial infarctions
Angina Pectoris 86/196 (43.9) Cross-sectional, 1-year retrospective study. ≥20 year-olds from Degerfors area. Elo [14] 19084244 2009 Data were obtained from IPR, hospital-based outpatient care and primary health care
Acute coronary syndrome (MI or unstable angina pectoris) IPR from emergency department missed 2% of 218 patients with acute coronary syndrome. Discharge diagnoses from emergency department, Lund University Hospital. Forberg [66] 18804783 2009 MR. The study evaluates different methods to identify acute coronary syndrome in patients, using information not available in the IPR (e.g. ECG measurements).
Non-specified ischemic heart disease 44/206 (21.4) Cross-sectional, 1-year retrospective study. ≥20 year-olds from Degerfors area. Elo [14] 19084244 2009 Data were obtained from IPR, hospital-based outpatient care and primary health care
Stroke (non-subarachnoidal hemorrhage) 318/377 (84.4) Data from a local stroke incidence study at the Örebro University Hospital. Appelros - (PC, Feb 22) Local stroke incidence study
Non-fatal strokes 3492/3732 (93.6) of all cases
3492/3562 (98.0) of estimated hospital cases
Patients aged 25-74 years in 1985-89. Criteria for acute stroke from MONICA study were comparable to WHO criteria. Stegmayr [38] 1291884 1992 MONICA-population based stroke register
Stroke 75/79 (95)   Merlo [63] 10870938 2000 The Skaraborg Hypertension Study
Stroke 76/81 (94)   Merlo [63] 10870938 2000 "Men born 1914"
Stroke 384/456 (84.2) First-time stroke. Restricted to the Lund county. Hallström [67] 17156265 2007 *
Stroke/Transient ischemic A. 217/232 (93.5) ULSAM. Wiberg - (PC, Feb 12) ULSAM
Hypertension 5,886/42,796 (13.7) IPR data from the county Östergötland. Wiréhn [68] 17786807 2007 County registers of primary health care, outpatient hospital care and inpatient care
Hypertension 74/838 (8.8) Cross-sectional, 1-year retrospective study. ≥20 year-olds from Degerfors area. Elo [14] 19084244 2009 Data were obtained from IPR, hospital-based outpatient care and primary health care
Gestational
hypertension
108/166 (65.1)   Zetterström - (PC, March 3) All pregnant women in Sweden have their blood pressure examined.
Lipid disorders 19/186 (10.2) Cross-sectional, 1-year retrospective study. ≥20 year-olds from Degerfors area. Elo [14] 19084244 2009 Data were obtained from IPR, hospital-based outpatient care and primary health care
Autoimmune/immune-mediated diseases
Rheumatoid arthritis (RA) 489/1150 (42.5) Malmö, Sweden, 1990-1994. According to the RA criteria of the American College of Rheumatology [41]. Turesson [42] 10461483 1999 Data from all rheumatologists and general practictioners in Malmö city, 1997
Diabetes, type 1 and 2* 92/394 (23.3) Cross-sectional, 1-year retrospective study. ≥20 year-olds from Degerfors area. Elo [14] 19084244 2009 Data were obtained from IPR, hospital-based outpatient care and primary health care
Type 1 and type 2 diabetes mellitus * 349/436 (80.0) patients with diabetes in "source 1" could be identified in the IPR The researchers evaluated the presence of type 1 or type 2 diabetes among patients with atrial fibrillations at the Södersjukhuset Hospital. All but 8 patients in this validation had type 2 diabetes. Friberg - (PC, Feb 8) MR + biochemistry data + data on insulin or other medication against diabetes
Type 1 and type 2 diabetes mellitus* 4,348/18,134 (24.0) IPR data from the county Östergötland. Wiréhn [68] 17786807 2007 County registers of primary health care, outpatient hospital care and inpatient care
Both type 1/2 diabetes and foot ulcer 235/280 (83.9) admissions could be identified through the IPR Based on 117 patients with deep foot infections and type 1 or 2 diabetes, referred to multidisciplinary foot-care team. Specificity for foot ulcers and concomitant diabetes was 98%. Ragnarson- Tennvall [46] 11123504 2000 MR
Infectious disease
CNS infection in intensive care ICD-9: 21/22 (95.4)
ICD-10: 21/28 (75.0)
Specificity was 99.6% (ICD-9) and 99.7% (ICD-10). IPR data obtained through both primary and secondary diagnoses. Gedeborg [69] 17208121 2007 ICU database diagnoses as reference
Pneumonia in intensive care ICD-9: 89/185 (48.1)
ICD-10: 116/221 (52.5)
Specificity was 95.9% (ICD-9) and 95.8% (ICD-10). IPR data obtained through both main and secondary diagnoses.
Using only primary diagnoses for pneumonia the specificity increased slightly but the sensitivity decreased to 31.2% and 38.2% respectively.
Gedeborg [69] 17208121 2007 ICU database diagnoses as reference
Sepsis in intensive care ICD-9: 85/186 (45.7)
ICD-10: 94/179 (52.5)
Specificity was 97.5% (ICD-9) and 92.6% (ICD-10). IPR data obtained through both main and secondary diagnoses. Gedeborg [69] 17208121 2007 ICU database diagnoses as reference, with inclusion in sepsis trials (IST) as secondary reference
Tuberculosis 12/15 (80) Evaluation in patients with concomitant rheumatoid arthritis Askling [70] 15986370 2005 MR
Other disorders
Carotid, infrainguinal bypass and aortic aneurysm (AAA) procedures 10,861/11,638 (93.3) of patients identified through Swedvasc (Svenska kärlregistret) or the IPR could be identified in the IPR (Swedvasc) started in 1987 and became nationwide 1994. In the paper by Troëng et al data on infraingunal and carotid bypass originated from 5 years (2000-2004), while data on aortic aneurysms originated from 1 year (2006). Divided the sensitivity figures were: Carotid 96.8%; Infrainguinal 92.3% and aortic aneurysm 88.9%. Troëng [15]
And by
18851920 2008 The Swedish Vascular Register (Swedvasc)
Asthma 1,377/18,451 (7.5) IPR data from the county Östergötland. Wiréhn [68] 17786807 2007 County registers of primary health care, outpatient hospital care and inpatient care
Dementia 23/87 (26) Participants originated from the study "Aging in women and men: a longitudinal study of gender differences in health behaviour and health among the elderly (as part of the Swedish Twin Register). The specificity for dementia was 97% (399/411) Dahl [71] 18007116   MR + memory test scores etc.
Dementia 41.3% for prevalent cases and 42.3% for incident cases. Participants originated from the study "Aging in women and men: a longitudinal study of gender differences in health behaviour and health among the elderly (as part of the Swedish Twin Register). The specificity for dementia was 97% (399/411) Rizutto   (PC, May 14) Comparison between cases detected in IPR with cases derived from the Kungsholmen (KP) and SNAC-K Projects [72]
Foot ulcer (only) 249/280 (88.9%) of admissions could be identified through the IPR Based on 117 patients with deep foot infections and type 1 or 2 diabetes, referred to multidisciplinary foot-care team. Ragnarson- Tennvall [46] 11123504 2000 MR
Chronic obstructive pulmonary disease 1,290/4,812 (26.8) IPR data from the county Östergötland. Wiréhn [68] 17786807 2007 County registers of primary health care, outpatient hospital care and inpatient care
  1. PC, Personal communication: All personal communications took place in 2010 (exact date is listed in the table).
  2. ICU, Intensive Care Unit. MI, Myocardial Infarction. MR, compared with Medical Records (patient charts). RA, Rheumatoid arthritis.
  3. ULSAM, Uppsala Longitudinal Study of Adult Men) cohort.
  4. *Data from all departments at the Lund Hospital including the emergency unit, general practitioners, community nurses, physicians at the Neurology department, autopsy registers, Forensic department, computerized searches of outpatient medical records