Growth-differentiation factor-15 and functional outcome after acute ischemic stroke

Blood biomarkers may improve the performance in predicting early stroke outcome beyond well-established clinical factors. We investigated the value of growth-differentiation factor-15 (GDF-15) to predict functional outcome after 90 days in a prospectively collected patient cohort with symptoms of acute ischemic stroke. Two hundred eighty-one patients with symptoms of acute ischemic stroke were prospectively investigated. Serial blood samples for GDF-15 analysis were obtained after the admission of the patient, after 6 and 24 h. Primary outcome was the dichotomized modified ranking scale (MRS) 90 days after the initial clinical event. Within the final study population (264 patients, mean age 70.3 ± 12.7 years, 55.3% male), National Institutes of Health Stroke Scale (NIH-SS) [odds ratio (OR) 1.269, 95% confidence interval (CI) 1.141-1.412, p < 0.001] and initial GDF-15 levels (OR 1.029, 95% CI 1.007-1.053, p = 0.011) were independently associated with a MRS ≥ 2 after day 90 after multiple regression analysis. Growth-differentiation factor-15 levels increase with higher NIH-SS-tertiles (p = 0.005). Receiver-operator characteristic curves demonstrated a discriminatory accuracy to predict unfavourable stroke outcome of 0.629 (95% CI 0.558-0.699), 0.753 (95% CI 0.693-812) and 0.774 (95% CI 0.717-0.832) for GDF-15, NIH-SS and the combination of these variables. The additional use of GDF-15 to NIH-SS ameliorates the model with a net reclassification index of 0.044 (p = 0.541) and integrated discrimination improvement of 0.034 (p = 0.443). Growth-differentiation factor-15 as an acute stroke biomarker independently predicts unfavourable functional 90 day stroke outcome. Discriminatory value in addition to NIH-SS is only modestly distinct.