Study area
This study was conducted at an outpatient department of TBGH, Addis Ababa, Ethiopia. The hospital is fully organized and launched in 2011 with a total number of 376 employees. Now a days, it is estimated to give service for about 605,266 peoples per year. Patients with DM have gotten the treatment in the chronic disease case team of the medical ward. The hospital has also given the psychiatric service at the outpatient level.
Study design and period
This was an institution-based cross-sectional study conducted from February 8 to April 8, 2019.
Source and study population
All diabetic patients who were on follow up at the outpatient department were the source population. All patients with DM who came to follow up during the data collection period were considered as the study population.
Inclusion and exclusion criteria
All diabetic patients aged≥18 years and communicating independently were included. Those who were taking antidepressant drugs for their depressive symptoms were excluded because antidepressant drugs can mask depression signs and symptoms. DM patients who were newly diagnosed at the time of data collection were not part of the study because in a newly diagnosed patient, adjustment disorder is more common than a full-blown depressive symptom [21]. Finally, DM patients who were seriously ill were excluded from this study.
Study variables
The dependent variable was depression. Independent variables included sociodemographic factors (age, sex, marital status, ethnicity, religion, educational and occupational status), clinical factors (type of DM, FBG level, duration of DM, type of treatment), and psychosocial factors (social support).
Sample size determination
Single population proportion formula was used to estimate the minimum numbers of samples required for this study. The sample size was calculated with the assumptions of 40.4% prevalence of depression from studies conducted in Felege-Hiwot referral hospital, Bahir Dar [17], 0.4 P, 1.96 Z (standard normal distribution), 95% CI, ⍺ = 0.05, and a 10% non-response rate. Accordingly, a representative sample was calculated to be 407.
Sampling technique and procedure
Participants were selected for interviews using the systematic random sampling technique. Before the data collection, the total number of diabetic patients who visited the hospital in 2018 was taken from patients’ record. Then the average number of diabetic patients over 2 month’s period was calculated and found to be 930. The sampling interval(k) was determined by dividing the expected number of diabetic patients expected to have a follow-up visit at the time of the data collection to the calculated sample size (K = 930/407 ≈ 2). Finally, eligible individuals were interviewed for every 2 intervals based on the order of their clinical evaluation at the outpatient department until the required sample size was reaching.
Method of data collection and tools
Data were collected by face-to-face interviews using a pretested semi-structured questionnaire consisting of socio-demographic factors, clinical characteristics, Oslo 3 item social support scale and patient health questionnaire-9 (PHQ-9). The questionnaire of socio-demographic and clinical related information was assessed by using questionnaires adapted from reviewing similar related articles and the patients’ medical record.
The outcome variable (depression) was measured by the nine items of the PHQ-9 tool, validated in east Africa including Ethiopia with a sensitivity and specificity 86 and 67% respectively [22]. It consists of nine items on a four-point Likert scale and scores each of nine DSM-IV criteria for depression [23]. Patients were expected to recall the depressive symptoms which were happening within 2 weeks period and the responses range from 0- (not) to 3- (nearly every day). PHQ-9 score ≥ 5 was considered having depression. The level of social support was assessed by using the Oslo 3 social support scale by asking the patients to rate the level of support they received from family and friends. It is validated in different African countries. The scale ranged from 3 to 14. Poor, intermediate and strong social support was considered for participants who scored 3–8, 9–11 and 12–14 out of 14 respectively [24].
Data quality assurance
The questionnaire was translated from English to Amharic and back translation to English was done to check its consistency. Before the actual data collection, the Amharic version of the questionnaire was pretested on 5% of the total study participants. Based on the pretest result, a minor modification was done regarding the contents of the questionnaire. Data collectors were trained on the content of the questionnaire and data collection procedures.
Data processing and analysis
All collected data were checked for completeness and consistency and entered into Epi-data version 3.1 and then exported to SPSS version 23 software for analysis. Descriptive statistics (frequencies, tables, percentages, and means) were computed to explain the socio-demographic characteristics, clinical variables, and depression. Bivariate and multivariate logistic regression analyses were done. Variables that have p-value < 0. 20 in the bivariate model were entered into the multivariate analysis to avoid potential confounders. In the multivariate model, variables with P-values of less than 0.05 were considered as statistical predictors of depression. The odds ratio with a 95% confidence interval was used to measure the strength of the association.