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.