Validation of the Stroke Prognostic Instrument-II in a Large, Modern, Community-Based Cohort of Ischemic Stroke Survivors

Abstract

Background and Purpose— The risk of recurrent stroke in the modern era of secondary stroke prevention is not well defined. Several prediction models, including the Stroke Prognostic Instrument-II (SPI-II), have been created to identify patients at highest risk, but their performance in modern populations has been infrequently tested. We aimed to assess the 1-year risk of recurrence after hospital discharge in a recent, large, community-based cohort of patients with ischemic stroke and to validate the SPI-II prediction model in this cohort. Methods— From 2004 through 2006, 5575 patients with acute ischemic stroke were prospectively identified and followed for recurrent events. Kaplan-Meier statistics were used to analyze the cumulative incidence of recurrent ischemic stroke. Harrell c-statistic was calculated to determine the performance of SPI-II in predicting stroke or death at 1 year, and the log-rank test was used to compare the differences among low-, middle-, and high-risk groups. Results— Among 5575 patients with ischemic stroke, recurrence was observed in 221 during the subsequent year. Kaplan-Meier estimates of cumulative rates of recurrent stroke were 2.5%, 3.6%, and 4.8% at 3, 6, and 12 months, respectively. Rates of stroke or death for SPI-II in the low-, middle-, and high-risk groups were 8.2%, 24.5%, and 35.6%, respectively (trend, P =0.001). The c-statistic for SPI-II was 0.62 (95% CI, 0.61–0.64). Conclusions— The modern 1-year rate of recurrent stroke after hospital discharge is low but still substantial at 4.8%. SPI-II is a modestly effective tool in identifying patients with ischemic stroke at highest risk of developing recurrence or death.