Short-term, intermediate-term, and long-term mortality in patients hospitalized for stroke

Abstract 

Cerebrovascular disease is the third leading cause of death and the primary cause of long-term disability in the United States. Although the risk factors for stroke have been well defined, less is known about stroke mortality over varying time periods within the same cohort of patients. The purpose of this study is to define rates of short-term, intermediate-term, and long-term stroke mortality among patients experiencing a first-ever hemorrhagic or ischemic stroke between 1994 and 1998. Patients were identified from the Patient Treatment Files of the Department of Veterans Affairs (VA). We included all patients who were discharged from a VA inpatient facility with a diagnosis of acute stroke. Patients were excluded from the study if they had an admission within the previous 5 years for stroke or hemiplegia. We obtained information on the patient's age, gender, and coexisting illnesses. Unadjusted and adjusted 30-day mortality rates were computed using Kaplan-Meier analyses and Cox proportional hazards regression models. The survival-dependent Cox proportional hazards regression models were run for 31–90 days and 91–365 days from the index admission date, for patients who had survived to the start of each of these time periods. Separate models were run for ischemic (n = 34,866 patients) and hemorrhagic (n = 5,442 patients) strokes. Unadjusted 30-day mortality was 8.2 and 20.5% for ischemic and hemorrhagic strokes, respectively. The adjusted 30-day mortality rate was 7.4 and 18.8% for ischemic and hemorrhagic strokes, respectively. For ischemic stroke, age 65 years and older was associated with an increased risk for short-term, intermediate-term, and long-term mortality, while chronic heart failure was associated with an increased risk for short-term and long-term mortality. For hemorrhagic stroke, age 75 years and older, malignancy, and chronic heart failure were associated with increased mortality during all three time periods. Thirty-day mortality is over two times greater following hemorrhagic stroke vs. ischemic stroke. For patients who survive 30 days after an ischemic stroke, the risk factor that remains significantly associated with long-term mortality, which may be improved with appropriate process of care, is chronic heart failure. For patients with a hemorrhagic stroke, variables that remain significantly associated with increased short-term and long-term mortality include malignant neoplasm and chronic heart failure. Information on stroke mortality is important for patients, physicians, and researchers. In addition to stroke treatment, clinicians must be able to provide families of stroke victims with appropriate prognostic information. Further work is needed to assess the impact of actual care patterns, for the above identified risk factors, on stroke prognosis over varying time periods.

Keywords:  Stroke mortality, Ischemic stroke, Hemorrhagic stroke