Background: BDNF (brain-derived neurotrophic factor) has been implicated in cardiovascular homeostasis and ischemic stroke pathogenesis. We aimed to prospectively investigate the associations between serum BDNF levels and the prognosis of ischemic stroke in a multicenter cohort study.
Methods: This prospective study follows the STROBE reporting guideline. Serum BDNF concentrations were measured in 3319 ischemic stroke patients from the China Antihypertensive Trial in Acute Ischemic Stroke between August 2009 and May 2013 in 26 hospitals across China. The primary outcome was the composite outcome of death and major disability (modified Rankin Scale score ≥3) at 3 months after stroke onset. Multivariate logistic regression or Cox proportional hazards regression analysis was used to assess the associations between serum BDNF levels and adverse clinical outcomes.
Results: During the 3-month follow-up period, 827 (24.92%) patients experienced a primary outcome, including 734 major disabilities and 93 deaths. After adjusting for age, sex, and other important prognostic factors, elevated serum BDNF levels were associated with decreased risks of primary outcome (odds ratio, 0.73 [95% CI, 0.58-0.93]), major disability (odds ratio, 0.78 [95% CI, 0.62-0.99]), death (hazard ratio, 0.55 [95% CI, 0.32-0.97]), and the composite outcome of death and vascular events (hazard ratio, 0.61 [95% CI, 0.40-0.93]) when 2 extreme tertiles were compared. Multivariable-adjusted spline regression analyses showed a linear association between serum BDNF levels and the primary outcome (P value for linearity=0.005). The addition of BDNF to conventional risk factors slightly improved reclassification for the primary outcome (net reclassification improvement: 19.33%; P<0.001; integrated discrimination index: 0.24%; P=0.011).
Conclusions: Elevated serum BDNF concentrations were independently associated with decreased risks of adverse outcomes after ischemic stroke, suggesting that serum BDNF may be a potential biomarker for prognosis after ischemic stroke. Further studies are warranted to investigate the potential therapeutic benefit of BDNF for ischemic stroke.
Keywords: biomarker; ischemic stroke; odds ratio; prognosis; risk factors.