Estimates and Predictors of Mortality, Stroke Recurrence, and Functional Dependency 1-Year after Ischemic Stroke: A Prospective Multicenter Longitudinal Cohort Study in Central Norway

Abstract

Background. Stroke incidence and mortality have drastically decreased in high-income countries in the past twenty years. In this study, we provide updated estimates on mortality, recurrent stroke, and functional dependency among patients with first-ever ischemic stroke and assess predictors associated with poor outcomes with a focus on age, vascular factors, stroke severity, function, and comorbidity burden. Methods. MIDNOR STROKE is a multicenter prospective longitudinal study including patients with first-ever ischemic stroke admitted to stroke units in Central Norway during 2015-2017. Data on survival, stroke recurrence, and functional dependency were collected during hospital stay and follow-up. Multivariable Cox proportional hazard models and logistic regression models were used to analyze predictors of mortality, stroke recurrence, and functional dependency. Results. A total of 794 participants were included in the study. After a year, 7.6% of the participants had died, 5.8% had a recurrent stroke, and 13.6% experienced functional deterioration to dependency. Multivariable analysis revealed that age (HR: 1.07, 96% CI: 1.03, 1.10), stroke severity (HR: 1.10, 95% CI: 1.07, 1.13), comorbidity burden (low: HR: 4.05, 95% CI: 1.48, 11.10; moderate: HR: 5.44, 95% CI: 2.06, 14.40; and high: 7.72, 95% CI: 2.85, 21.00), and coronary artery disease (HR: 2.40, 95% CI: 1.32, 4.38) predicted all-cause death. Statin therapy predicted improved survival (HR: 0.39, 95% CI: 0.21, 0.75). High age (HR: 1.09, 95% CI: 1.05, 1.14) and increased stroke severity (OR: 1.26, 95% CI: 1.17, 1.38) predicted elevated risk of functional dependency at one year. Conclusions. In this study, we have demonstrated that 1-year survival following first-ever ischemic stroke was high compared to previous reports and that statin therapy predicted improved survival. The risk of recurrent stroke after one year was found to be low compared to previous studies. Approximately 14% of stroke survivors who were initially functionally independent experienced deterioration to functional dependency. In addition to older age and stroke severity, increased comorbidity burden and a history of coronary artery disease predicted poor stroke prognosis. Interventions aimed at reducing stroke severity may improve patient outcomes. Furthermore, prevention efforts targeting conditions such as CAD and reducing overall comorbidity burden in stroke patients may favorably improve survival. This trial is registered with NCT03962127.