Background and aims: High levels of inflammatory markers shortly after an ischemic stroke are associated with a worse prognosis. Whether inflammatory markers predict long-term mortality in stroke-survivors is less clear. We examined whether a persisting inflammatory response (levels of inflammatory markers >1 year after the stroke event) was associated with long-term mortality.
Methods: We recruited participants from the Tromsø Study, Norway, in a nested case-control design. At baseline in 1997, white blood cell count (WBC), serum levels of fibrinogen, interleukin 6 (IL-6) and high sensitive C-reactive protein (hs-CRP) were analysed in 187 stroke-survivors, a median of 7.0 years (range 1-43) after the first-ever ischemic stroke, and in 243 stroke-free subjects. Cox proportional hazard regression model was used to examine whether inflammatory markers predicted all-cause mortality in both groups from 1997 to 2013.
Results: During an average of 16 years follow-up, 117 (62.5 %) stroke-survivors and 107 (44.0 %) stroke-free subjects deceased (p for differences 0.005). In stroke-survivors, fibrinogen and log IL-6 predicted all-cause mortality after adjustment for age, sex, BMI, smoking, Frenchay activity index, comorbidity and use of statins (HRs 1.26; 9 5 % CI 1.05-1.51 and 2.02; 95 % CI 1.12-3.64, respectively). In stroke-free subjects log hs-CRP predicted all-cause mortality after additionally accounting for levels of cholesterol, blood pressure and use of blood pressure lowering drugs (HR 1.95; 95 % CI 1.26-2.99).
Conclusions: Fibrinogen and IL-6 were independent predictors of mortality in long-term stroke-survivors, whereas elevated hs-CRP predicted mortality in stroke-free subjects. Mortality risk prediction in stroke-survivors differed from that of stroke-free subjects.
Keywords: CRP; High sensitive-CRP; Inflammatory markers; Interleukin-6; Mortality; Stroke.