Death by suicide and other externally caused injuries after stroke in Japan (1990-2010): the Japan Public Health Center-based prospective study

No large population-based prospective study has investigated the risks of suicide and death by other externally caused injuries (ECIs) among stroke patients. The purpose of this study was to examine whether stroke increases the risks of suicide and ECI deaths. We analyzed data from the Japan Public Health Center-based Prospective Study between 1990 and 2010. Poisson regression models were used to calculate adjusted risk ratios (RR) for suicide and ECI deaths. To adjust for unmeasured confounders, case-crossover analyses of all stroke patients who died by suicide and ECIs were also performed. A population-based cohort of 93,027 Japanese residents was established. During the follow-up period, 4793 residents had been diagnosed as having stroke. During this period, there were 22 suicides and 53 ECI deaths among stroke patients and 490 suicides and 675 ECI deaths among those who were stroke-free. Stroke patients were at increased risk for death by suicide and ECIs within the first 5 years after a stroke (suicide: RR = 10.2, 95% confidence interval [CI] = 6.3-16.6; ECI: RR = 12.8, 95% confidence interval = 9.0-18.2). Furthermore, case-crossover analyses confirmed the results of the Poisson regression models. The RRs of suicide and ECI deaths within the first 5 years after a stroke were noticeably high. These findings underscore the need for clinicians and health care professionals to be aware of causes of death after a stroke and closely monitor patients during the first few poststroke years.