Author Response for "low Vitamin D Levels and the Long‐term Functional Outcome of Stroke Up to 5 Years"

Background and purpose Previous studies have established that vitamin D was associated with stroke. The purpose of this study was to investigate the relationship between vitamin D and 5-year outcome of patients with stroke including acute ischemic stroke (AIS) and intracranial hemorrhage (ICH) stroke. Methods Serum 25-hydroxyvitamin D levels were prospectively analyzed in patients admitted to the First Affiliated Hospital of Wenzhou Medical University from 2013 to 2015. Modified Rankin scale (mRS) was used to evaluate their 5-year functional outcome, and univariate and multivariate logistic regressions were applied to evaluate the effects of vitamin D on stroke outcome. Results In total, 668 patients diagnosed with stroke were recruited, and 420 completed the 5-year follow-up. Ninety-five patients experienced poor outcome in the 5 years since stroke onset. Vitamin D levels in patients with poor outcome showed significant differences compared to good outcome patients (p < .001). In multivariable logistic regression analysis, after adjusting the potential confounders, the 5-year functional outcome was significantly associated with vitamin D levels. Stroke patients with vitamin D levels less than 38.4 nmol/L had a higher risk for poor outcome compared with those with vitamin D level over 71.4 nmol/L at 5-year (odds ratio [OR] = 3.66, 95% confidence interval [CI] = 1.42-9.45, p = .007), which was consistent with AIS patients (OR = 6.36, 95% CI = 1.89-21.44, p = .003). Conclusion Vitamin D level less than 38.4 nmol/L at admission is a potential risk biomarker for poor functional outcome at 5-year prognosis in AIS patients, which might provide new ideas for the prognostic assessment of stroke.