Vascular mortality in participants of a bipolar genomics study

Background: In prior work, we identified a relationship between symptom burden and vascular outcomes in bipolar disorder.

Objective: We sought to replicate these findings using a readily accessible measure of mood disorder chronicity and vascular mortality.

Methods: We conducted a mortality assessment using the National Death Index for 1716 participants with bipolar I disorder from the National Institute of Mental Health Genetics Initiative Bipolar Disorder Consortium. We assessed the relationship between the duration of the most severe depressive and manic episodes and time to vascular mortality (cardiovascular or cerebrovascular) using Cox proportional hazards models, adjusting for potentially confounding variables.

Results: Mortality was assessed a mean for 7 years following study intake, at which time 58 participants died, 18 of vascular causes. These participants had depression for much longer than their counterparts did (Wilcoxon rank sum Z = 2.30, p = 0.02) and the duration of the longest depressive episode in years was significantly associated with time to vascular mortality in models (hazard ratio = 1.16, 95% confidence interval: 1.02-1.33, p = 0.02), which controlled for age, gender, vascular disease equivalents, and vascular disease risk factors. The duration of longest mania was not related to vascular mortality.

Conclusion: The duration of the most severe depression is independently predictive of vascular mortality, lending further support to the idea that mood disorders hasten vascular mortality in a dose-dependent fashion. Further study of the relevant mechanisms by which mood disorders may hasten vascular disease and of integrated treatments for mood and cardiovascular risk factors is warranted.