Patients with diabetes and comorbid depressive disorders may have higher rates of macrovascular complications and all-cause mortality, according to the results of a cohort study conducted with Taiwan’s National Health Insurance Research Database (NHIRD) and published in Epidemiology and Psychiatric Sciences.
The investigators sought to evaluate whether the presence of depression increases an individual’s risk for complications from diabetes and mortality among incident patients with diabetes. Through the NHIRD, they identified incident patients with diabetes ≥20 years of age. The first date of a patient’s antidiabetic prescription was defined as the cohort entry date. Individuals with macrovascular or microvascular complications before or on the cohort entry date, as well as those with a diagnosis of schizophrenia or bipolar disorder, were excluded from the study. The composite study endpoint was the development of macrovascular and microvascular complications, cause-specific mortality, and all-cause mortality.
The current study enrolled a total of 38,537 incident patients with diabetes who had depressive disorders and 154,148 patients with diabetes without depression. All participants were randomly selected and matched according to sex, age, and cohort entry year. The average study follow-up time was 5.5 years (range, 0 to 14 years); the mean age of the participants was 52.61±12.45 years; and 39.63% were male.
The crude incidence of macrovascular complications was 74.65 per 1000 person-years among those with diabetes and comorbid depressive disorders, which was higher than the incidence of 54.65 per 1000 person-years reported among patients without depression. Similar findings were reported with respect to the crude incidence of mortality due to cardiovascular disease (2.58 per 1000 person-years vs 2.29 per 1000 person-years, respectively); unnatural mortality (2.46 per 1000 person-years vs 0.77 per 1000 person-years, respectively); suicide (1.41 per 1000 person-years vs 0.27 per 1000 person-years, respectively); and all-cause mortality (21.91 per 1000 person-years vs 15.96 per 1000 person-years, respectively). No differences were shown between the groups regarding microvascular complications and mortality due to diabetes.
Following adjustment for covariates, participants with diabetes and comorbid depression had a significantly higher risk for developing macrovascular complications (hazard ratio [HR], 1.35; 95% CI, 1.32 to 1.37), unnatural mortality (HR, 2.59; 95% CI, 2.30 to 2.91), suicide (HR, 5.64; 95% CI, 4.70 to 6.77), and all-cause mortality (HR, 1.08; 95% CI, 1.04 to 1.12). In contrast, no statistically significant differences in microvascular complications or death due to cardiovascular disease were observed between the groups.
The investigators concluded that additional research is warranted, focusing on the risks and the benefits of treatment for depression on outcomes among individuals with diabetes. They noted that the study was limited by potential inclusion of patients who were not diagnosed with or treated for depression in the comparison group. Information on smoking, body weight, exercise routines, and diet control were not available in NHIRD as well.
The researchers concluded, “Although we could not directly measure lifestyle behaviours in this study, we found that patients with depression had a higher prevalence of dyslipidemia, alcohol- or substance-related disorders and chronic pulmonary diseases, which are highly related to an unhealthy lifestyle.”
Wu C-S, Hsu L-Y, Wang S-H. Association of depression and diabetes complications and mortality: a population-based cohort study [published online Jan 29, 2020]. Epidemiol Psychiatr Sci. 2020;29:e96. doi: 10.1017/S2045796020000049.