IL-6 is a Predictive Biomarker for Stroke Associated Infection and Future Mortality in the Elderly After an Ischemic Stroke

Background And Purpose: Stroke associated infection (within the first seven days) occurs in approximately half of stroke patients and is associated with a worse prognosis, especially in the elderly. It is uncertain what factors predict stroke associated infection, yet identification of a suitable biomarker for infection may allow early and appropriate intervention with antibiotics. The aims of this study were to: a) identify independent risk factors for stroke associated infection, and b) test relationships between these risk factors and mortality at 2 years.

Methods: Eight-two elderly patients were assessed within 72 h of stroke. Data on stroke severity (Barthel Index), stroke associated infection and mortality at 2 years were collected. Inflammatory biomarkers at baseline and 6 months were measured by ELISA. Logistic regression was used to identify risk factors for stroke associated infection and death.

Results: Patients with stroke associated infection, especially pneumonia, had increased IL-6, more severe strokes, and higher mortality. IL-6 was independently associated with stroke associated infection (OR = 19.2, [95%CI 3.68, 100], p < 0.001), after adjustment for other risk factors and cytokines. IL-6 was also independently associated with 2 year mortality (OR = 9.2, [1.0, 85.1], p = 0.031).

Conclusions: These data suggest that IL-6 may be a key biomarker for predicting stroke associated infection and mortality in the first two years post stroke.