Impact of vitamin D supplementation on the outcome of tuberculosis treatment: a systematic review and meta-analysis of randomized controlled trials

Background Vitamin D supplementation is believed to be beneficial in the treatment of patients with tuberculosis(TB), however, results from clinical trials have been inconclusive. Methods We performed a systematic literature search across MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, Springer, EBSCO, Pro Quest, High Wire Press, and Web of Science, published as of December 2013. We individually inspected citations and extracted data independently. We estimated pooled risk ratios(RR) and 95% confidence intervals(CI) using random-effect models. We also assessed risk of bias using the Jadad scale and the quality of the evidence using GRADE. We included all randomized controlled trials comparing vitamin D with or without standard TB therapy or placebo.Results A total of five studies were analyzed in our meta analysis covering 841 newly-diagnosed TB cases. Patients receiving vitamin D supplementation had a 39% reduced risk of sputum smear or culture positive after six weeks of antiTB treatment than those in the control group, although this is not statistically significant(pooled RR 0.61, 95% CI 0.24 to 1.56, P=0.30). Apart from an increased serum vitamin D level in the supplement group after eight weeks of treatment there was no evidence of any additional adverse effects related to vitamin D.Conclusions The meta analysis results indicate that vitamin D supplementation does not seem to have any beneficial effect in the treatment of TB. Future rigorous randomized controlled trials are needed to explore whether the supplementation of vitamin D could shorten treatment duration and to confirm whether the polymorphisms of vitamin D receptor have any potentially beneficial effect.