Prognostic utility of serum 25-hydroxyvitamin D in patients with stroke: a meta-analysis

Background Conflicting findings have been reported on the prognostic significance of serum 25-hydroxyvitamin D level in patients with stroke. The objective of this meta-analysis was to evaluate the prognostic utility of serum 25-hydroxyvitamin D in stroke patients. Methods PubMed and Embase databases were systematically searched for potentially eligible studies until October 16, 2019. Observational studies investigating the association between serum 25-hydroxyvitamin D level and prognosis of patients with stroke were eligible. Multivariable adjusted risk ratios (RR) with 95% confidence intervals (CI) of poor functional outcome, all-cause mortality, and recurrence of stroke were pooled with the lowest versus the highest category of 25-hydroxyvitamin D level. Results Eleven articles (ten studies) involving 6845 stroke patients satisfied our predefined inclusion criteria. Lower serum 25-hydroxyvitamin D level was associated with an increased risk of poor functional outcome (RR 1.86; 95% CI 1.16–2.98), all-cause mortality (RR 3.56; 95% CI 1.54–8.25), and recurrence of stroke (RR 5.49; 95% CI 2.69–11.23). Sensitivity analysis further confirmed the above findings. Conclusions Lower serum 25-hydroxyvitamin D level is significantly associated with poorer prognosis in stroke patients. Future prospective studies are warranted to verify the prognostic role and to examine the association in different subtypes of stroke.