Serum 25-hydroxyvitamin D predicts severity and prognosis in stroke patients

Background and purpose: We aimed to evaluate the association between 25-hydroxyvitamin D (25(OH)D) levels and both clinical severity at admission and outcome at discharge in stroke patients.

Methods: From February 2010 to December 2010, consecutive stroke patients admitted to the Department of Neurology of Dijon, France, were identified. Clinical information was collected. Serum concentration of 25(OH)D was measured at baseline. Stroke severity was assessed at admission using the NIHSS score. Functional impairment was evaluated at discharge using the modified Rankin scale (m-Rankin). Multivariate analyses were performed using logistic regression models.

Results: Of the 386 recorded patients, serum 25(OH)D levels were obtained in 382 (median value = 35.1 nM; IQR = 21-57.8). At admission, 208 patients had a NIHSS ≤5, with a higher mean 25(OH)D level than that observed in patients with moderate-to-high severity (45.9 vs. 38.6 nM, P < 0.001). In multivariate analyses, a 25(OH)D level in the lowest tertile (<25.7 nM) was a predictor of a NIHSS ≥6 (OR = 1.67; 95% CI = 1.05-2.68; P = 0.03). The mean 25(OH)D level was lower in patients with moderate-to-severe handicap at discharge (m-Rankin 3-6) than in patients with no or mild handicap (35.0 vs. 47.5 nM, P < 0.001). In multivariate analyses, the lowest tertile of 25(OH)D level (<25.7 nM) was associated with a higher risk of moderate-to-severe handicap (OR = 2.06; 95% CI = 1.06-3.94; P = 0.03).

Conclusion: A low serum 25(OH)D level is a predictor of both severity at admission and poor early functional outcome in stroke patients. The underlying mechanisms of these associations remain to be investigated.