Associations of depression diagnosis and antidepressant treatment with mortality among young and disabled Medicare beneficiaries with COPD

Objective: Depression is prevalent in chronic obstructive pulmonary disease (COPD) patients and a risk factor for COPD exacerbation and death. The objective of this study was to determine the associations of depression diagnosis and antidepressant treatment with mortality among Social Security Disability Insurance (SSDI)-eligible (age < 65 years who had permanent physical or mental disabilities) Medicare beneficiaries with COPD. Method: This retrospective cohort study used a 5% random sample of SSDI-eligible Medicare beneficiaries with COPD in stand-alone Part D plans during 2006-2008 (n= 17,320). COPD and depression diagnoses were assessed during 2006. Evidence of antidepressant treatment was measured in 2006-2008. All-cause mortality was measured in 2007-2008. Cox proportional hazards models were used to examine the associations of depression diagnosis with mortality and, among depressed beneficiaries, antidepressant treatment (time dependent) with mortality after controlling for covariates. Results: More than one third (37.3%) of SSDI-eligible beneficiaries with COPD had a baseline depression diagnosis; of those, 86.8% had evidence of antidepressant treatment. Baseline depression diagnosis was an independent risk factor for 2-year mortality [hazard ratio (HR)=1.21; 99% confidence interval (CI)=1.07-1.37]. Among depressed beneficiaries, receiving antidepressant treatment was associated with significantly lower mortality (HR=0.55; 99% CI=0.44-0.68). Conclusion: Proactive antidepressant treatment should be considered as an intervention to reduce mortality for this young and disabled Medicare population.