Epidemiology and outcomes of depression following cardiovascular events in elderly Medicare beneficiaries

Abstract

Objective. To assess and compare elderly Medicare beneficiaries' occurrence of depression and associated treatment following a thrombotic cardiovascular event (TCE) for (1) annual prevalence rates, (2) healthcare services utilization outcomes in the first twelve months following a TCE, and (3) the occurrence of recurrent TCEs or death in the first twelve months following a TCE. Methods. Elders enrolled in the 1997 to 2002 Medicare Current Beneficiary Survey with a TCE (International Classification of Diseases, Ninth Revision (ICD-9) codes 410, 411, 413, 414, 415, 433--438, 452, or 453). Depression (ICD-9 codes 296.2, 296.3, 296.5, 296.6, 298.0, 300.4, 308.0, 309.0, 309.1, 309.4, or 311) was assessed by a claim within six months after the TCE. Demographic and descriptive characteristics were assessed. Prevalence rates of depression and associated antidepressant utilization rates by class were calculated. Time to first healthcare service use, recurrent TCE, and death were assessed using Cox-proportional hazard models. Counts of office visits were assessed using negative binomial regression models. Results. The sample included 7,051 elders with a TCE. The prevalence rate of depression was 7.6% across the study period. Close to 70% of elders with a depression claim were using an antidepressant in the year of depression diagnosis and 53% were using SSRI antidepressants. A depression claim was associated with 51% sooner hospitalization (95% CI = 1.31, 1.76), 56% sooner emergency department visit (95% CI = 1.29, 1.90), 19% sooner outpatient hospital visit (95% CI = 1.03, 1.38). Depression was associated with a shorter time to death (p = 0.008) in the unadjusted analysis; however not associated with time to death or recurrent events in adjusted analysis. Antidepressant use was not associated with any outcome. Conclusions. Prevalence rates of post-TCE depression were much lower than rates reported in previous studies. Depression is associated with more acute healthcare services and sooner during the first twelve months following a TCE; however not associated with time to recurrent event or death. Antidepressant use has no effect on outcomes.