Stroke-associated infection independently predicts 3-month poor functional outcome and mortality

Stroke-associated infection (SAI) is a common and serious complication of stroke. This study aimed to assess the effects of SAI on patient mortality and functional outcome at 3 months after stroke onset. We retrospectively analyzed 809 consecutive patients with acute stroke (517 men and 292 women; median age, 72 years) who were admitted to our department between September 2014 and June 2016. SAI was defined as an infection diagnosed during the hospitalization period. Poor outcome was defined as a modified Rankin Scale (mRS) score of 3-5 or death (mRS score of 6). The effect of SAI on functional outcome was evaluated using a multivariate logistic regression analysis. SAI occurred in 169 patients (20.9%); of these, 106 (62.7%) had pneumonia, 23 (13.6%) had a urinary-tract infection, and 40 (23.7%) had other types of infection. Patients with SAI were older, more likely to be female, had lower body mass indices, had higher stroke severity, and were more likely to have atrial fibrillation and a history of ischemic heart disease than patients without SAI. Poor functional outcome and mortality were more common in patients with SAI than in patients without SAI (poor functional outcome 41.8 vs. 4.8%, mortality 24.3 vs. 3.9%, respectively). After adjusting for age, sex, stroke severity, and various comorbidities, SAI was independently associated with poor functional outcome [odds ratio (OR) 6.88; 95% confidence interval (CI) 3.72-12.73] and mortality (OR 4.45, 95% CI 2.27-8.72) at 3 months after stroke onset. Our results suggest that SAI during the hospitalization period is independently associated with 3-month poor functional outcome and mortality.