Increased Serum Netrin-1 Is Associated With Improved Prognosis of Ischemic Stroke: An Observational Study From CATIS

Background and Purpose - Previous experimental studies suggested that serum netrin-1 was associated with the progression of ischemic stroke. Knowledge about netrin-1 among ischemic stroke patients may provide new ideas for the prognostic assessment of ischemic stroke. The aim of this study was to investigate the association between serum netrin-1 and prognosis of ischemic stroke. Methods - Serum netrin-1 levels at baseline were measured for 3346 ischemic stroke patients from the CATIS (China Antihypertensive Trial in Acute Ischemic Stroke), and all patients were followed up at 3 months after stroke onset. The primary outcome was a combination of death and major disability (modified Rankin Scale score of ≥3) within 3 months after stroke onset. Results - Up to 3 months after stroke onset, 845 patients (25.25%) experienced death or major disability. After adjustment for baseline National Institutes of Health Stroke Scale score and other potential confounders, elevated serum netrin-1 was associated with a decreased risk of primary outcome (odds ratio, 0.65; 95% CI, 0.47-0.88; P_trend=0.002) when 2 extreme quartiles were compared. Each SD increase of log-transformed netrin-1 was associated with 17% (95% CI, 7%-26%) decreased risk of primary outcome. Multivariable-adjusted spline regression models showed a negative linear dose-response relationship between serum netrin-1 and the risk of primary outcome (P_linearity=0.003). Adding netrin-1 quartile to a model containing conventional risk factors improved risk prediction for primary outcome (net reclassification improvement index =14.74%; P=0.002; integrated discrimination improvement =0.40%; P=0.005). Conclusions - Elevated serum netrin-1 levels were associated with improved prognosis at 3 months after ischemic stroke, suggesting that serum netrin-1 may be a potential prognostic biomarker for ischemic stroke. Further studies from other samples of ischemic stroke patients are needed to replicate our findings and to clarify the potential mechanisms. Clinical Trial Registration - URL: https://www.clinicaltrials.gov. Unique identifier: NCT01840072.