One-Month to 10-Year Survival in the Copenhagen Stroke Study: Interactions Between Stroke Severity and Other Prognostic Indicators

We studied the association of stroke severity with survival from 1 month to 10 years after stroke and explored how stroke severity interacts with other prognostic indicators with time. The study is based on 999 stroke patients from the community-based Copenhagen Stroke Study (mean age, 74.3 ± 11.0 years; 56% women; mean Scandinavian Stroke Scale [SSS], 38.0 ± 17.4).

Evaluation included stroke severity (based on the SSS), computed tomography scan, and a cardiovascular risk profile. Using logistic regression models, we examined the relevance of the SSS on mortality at 1 month and 1, 5, and 10 years. We analyzed the proportion of the variation explained by the models and bias of risk factors estimates with and without the SSS in the model.

Mortality rate was 16.6% at 1 month, 31.5% at 1 year, 60.2% at 5 years, and 81.3% at 10 years. In models including the SSS, 22.4%, 20.9%, 32.8%, and 39.5% of the variance was explained for the endpoints of 1 month, 1 year, 5 years, and 10 years, respectively. When SSS was left out of the model, the corresponding values were 6.9%, 13.3%, 29.0%, and 35.1%.

Factors significantly associated with survival were SSS at 1 month; SSS, age, diabetes, and stroke type at 1 year; SSS, age, sex, previous stroke, other complicating diseases, diabetes, smoking, and atrial fibrillation at 5 years; and SSS, age, sex, other complicating diseases, and diabetes at 10 years.

Our data suggest that stroke severity is significantly associated with short-term and long-term survival. It is the all-important predictor of short-term survival, whereas it is of less importance in predicting long-term survival.