Do socioeconomic factors modify the association between preoperative antidepressant use and survival following coronary artery bypass surgery?

BackgroundThe impact of socioeconomic factors on mortality in patients with depression and cardiovascular disease is unknown. The aim was to study if socioeconomic factors modified the association between preoperative depression and survival following CABG.MethodsIn a nationwide population-based cohort study, 22,930 patients who underwent CABG in Sweden between 2006 and 2013 were included from the SWEDEHEART register. The national Prescribed Drug Register was used to ascertain preoperative antidepressant use which was utilized as a proxy for depression. Educational level, income, and civil status were extracted from the Longitudinal integration database for health insurance and labor market studies. The primary outcome measure was all-cause mortality and was ascertained from the Cause of Death register. Cox regression and propensity score methods were used to estimate the risk for death while controlling for differences in baseline characteristics.ResultsDuring a mean follow-up of 4.1 years, 340 (11%) patients died in the antidepressant group and 1923 (9.7%) patients died in the control group. The adjusted risk for death was higher in patients with preoperative antidepressant use (HR 1.27; 95% CI 1.13–1.43), and was practically unchanged after the addition of educational level, family disposable income, and civil status (HR 1.25; 95% CI 1.11–1.41). The results were confirmed in a propensity-score matched cohort, and in selected subgroup analyses.ConclusionsAmong patients who underwent CABG in Sweden, preoperative antidepressant use was associated with worse survival even after controlling for socioeconomic factors. The clinical implication is that the impact of depression on mortality was not influenced by socioeconomic factors.