The incidence and relative risk of stroke in patients with schizophrenia: a five-year follow-up study

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

Methods: This study identified a study population from the National Health Insurance Research Database (NHIRD) between 1999 and 2003 that included 80,569 patients with schizophrenia and 241,707 age- and sex-matched control participants without schizophrenia. The participants were randomly selected from the 23,981,020-participant NHIRD, which consists of 96% Taiwanese participants. Participants who had experienced a stroke between 1999 and 2003 were excluded. Using data from the NHIRD between 2004 and 2008, the incidence of stroke (ICD-9-CM code 430-438) and patient survival after stroke were calculated for both groups. After adjusting for confounding risk factors, a Cox proportional-hazards model was used to compare the five-year stroke-free survival rate to the all-cause mortality rate across the two cohorts.

Results: Over five years, 1380 (1.71%) patients with schizophrenia and 2954 (1.22%) controls suffered from strokes. After adjusting for demographic characteristics and comorbid medical conditions, patients with schizophrenia were 1.13 times more likely to have a stroke (95% CI=1.05-1.22; P=0.0006). In addition, 1039 (24%) patients who had a stroke died during the follow-up period. After adjusting for patient, physician and hospital variables, the all-cause mortality hazard ratio for patients with schizophrenia was 1.23 (95% CI=1.06-1.41; P=0.0052).

Conclusions: During a five-year follow-up, the likelihood of developing a stroke and the all-cause mortality rate were greater among patients with schizophrenia as compared with the control group.