Vitamin D to prevent exacerbations of COPD: systematic review and meta-analysis of individual participant data from randomised controlled trials
Abstract
BACKGROUND:
Randomised controlled trials (RCTs) of vitamin D to prevent COPDexacerbations have yielded conflicting results.Individual participant data meta-analysis could identify factors that explain this variation.
METHODS:
PubMed, Embase, the Cochrane Central Register of Controlled Trials and Web of Science were searched from inception up to and including 5 October 2017 to identify RCTs of vitamin D supplementation in patients with COPD that reported incidence of acute exacerbations. Individual participant data meta-analysis was performed using fixed effects models adjusting for age, sex, Global Initiative for Chronic Obstructive Lung Disease spirometric grade and trial.
RESULTS:
Four eligible RCTs (total 560 participants) were identified; individual participant datawere obtained for 469/472 (99.4%) participants in three RCTs. Supplementation did not influence overall rate of moderate/severe COPD exacerbations (adjusted incidence rate ratio (aIRR) 0.94, 95% CI 0.78 to 1.13). Prespecified subgroup analysis revealed that protective effects were seen in participants with baseline 25-hydroxyvitamin D levels <25 nmol/L (aIRR 0.55, 95% CI 0.36 to 0.84) but not in those with baseline 25-hydroxyvitamin D levels ≥25 nmol/L (aIRR 1.04, 95% CI 0.85 to 1.27; p for interaction=0.015). Vitamin D did not influence the proportion of participants experiencing at least one serious adverse event (adjusted OR 1.16, 95% CI 0.76 to 1.75).
CONCLUSIONS:
Vitamin D supplementation safely and substantially reduced the rate of moderate/severe COPD exacerbations in patients with baseline 25-hydroxyvitamin D levels <25 nmol/L but not in those with higher levels.
TRIAL REGISTRATION NUMBER:
CRD42014013953.
RPR Commentary
The meta-analysis of 4 RCTs found that patients with COPD and 25-hydroxy Vitamin D levels below 25 had fewer moderate and severe COPD exacerbations if they were supplemented with Vitamin D. It suggests that COPD patients should have their Vitamin D levels measured periodically, and if their levels are below 25, they should be supplemented.