The incidence and relative risk of stroke among patients with bipolar disorder: a seven-year follow-up study

PLoS One. 2013 Aug 30;8(8):e73037. doi: 10.1371/journal.pone.0073037. eCollection 2013.

Abstract

Objective: This study aimed to estimate the incidence and relative risk of stroke and post-stroke all-cause mortality among patients with bipolar disorder.

Methods: This study identified a study population from the National Health Insurance Research Database (NHIRD) between 1999 and 2003 that included 16,821 patients with bipolar disorder and 67,284 age- and sex-matched control participants without bipolar disorder. The participants who had experienced a stroke between 1999 and 2003 were excluded and were randomly selected from the NHIRD. The incidence of stroke (ICD-9-CM code 430-438) and patient survival after stroke were calculated for both groups using data from the NIHRD between 2004 and 2010. A Cox proportional-hazards model was used to compare the seven-year stroke-free survival rate and all-cause mortality rate across the two cohorts after adjusting for confounding risk factors.

Results: A total of 472 (2.81%) patients with bipolar disorder and 1,443 (2.14%) controls had strokes over seven years. Patients with bipolar disorder were 1.24 times more likely to have a stroke (95% CI = 1.12-1.38; p<0.0001) after adjusting for demographic characteristics and comorbid medical conditions. In addition, 513 (26.8%) patients who had a stroke died during the follow-up period. The all-cause mortality hazard ratio for patients with bipolar disorder was 1.28 (95% CI = 1.06-1.55; p = 0.012) after adjusting for patient, physician and hospital variables.

Conclusions: The likelihood of developing a stroke was greater among patients with bipolar disorder than controls, and the all-cause mortality rate was higher among patients with bipolar disorder than controls during a seven-year follow-up period.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Bipolar Disorder / complications*
  • Bipolar Disorder / epidemiology*
  • Case-Control Studies
  • Comorbidity
  • Demography
  • Female
  • Follow-Up Studies
  • Humans
  • Incidence
  • Male
  • Physicians
  • Proportional Hazards Models
  • Risk Factors
  • Stroke / epidemiology*
  • Stroke / etiology*
  • Taiwan / epidemiology

Grants and funding

This research was supported by grants from Kai-Syuan Psychiatric Hospital. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.