Depression and Mental Health Disorders Increase Adjusted Risk of Death Post-Stroke
Background/Objectives: Post-stroke depression (PSD) has been linked to higher mortality after stroke. Whether PSD and other mental health (MH) diagnoses are independent risks for mortality is not known. The purpose of this study was to examine the relationship of depression and other MH diagnoses to mortality post-stroke. Methods: We examined a national cohort of veterans hospitalized at any VA Medical Center from 10/90–10/98. Index ischemic stroke admissions were defined as the first admission with primary discharge ICD-9 diagnosis code 434 or 436. Demographic, admission and all-cause mortality data were abstracted from VA administrative databases. ICD-9 codes at discharge were used to assess risk factors and to construct the Charlson Index, a measure of mortality risk. PSD within 1-year post-stroke was identified using ICD-9 codes. Other MH diagnoses during the entire period were also ascertained. We analyzed the data with and without patients who died < 365 days post-stroke, as patients with early death have less chance of receiving a 1-year PSD diagnosis. Hazard ratios (HR) were modeled using Cox regression. Results: We identified 55,094 patients with ischemic stroke, 40,171 survived > 365 days post-stroke. Mean age = 67 and 30% were non-white. 2,537 (6%) had depression within 1 year and 6,761 (17%) had another MH diagnosis. PSD increased adjusted relative mortality risk by 25% (HR 1.25, 95% CI 1.16–1.34). This increase was exceeded only by congestive heart failure (HR 1.39 95% CI 1.31, 1.48), was equal to that of atrial fibrillation (HR 1.25, 95%CI 1.18,1.32) and exceeded age, hypertension, diabetes and coronary artery disease (all HR < 1.21). Other MH diagnoses also increased adjusted relative mortality risk (HR 1.20, 95% CI 1.14, 1.26). Similar results were obtained with the model including patients who died < 365 days after stroke. Conclusions: PSD independently increases adjusted risk of all-cause mortality post-stroke. The magnitude of this risk equals many chronic cardiovascular conditions. Other MH diagnoses also increase adjusted mortality risk. Future studies should address whether treatment of these conditions can decrease mortality risk after stroke.