Efficacy of vitamin D supplementation for children with acute bronchiolitis: A randomized controlled trial

BACKGROUND Previous studies have suggested an association between vitamin D deficiency and bronchiolitis, but the therapeutic benefits of vitamin D supplementation remain uncertain. AIM To investigate the efficacy of vitamin D supplementation for hospitalized children with acute bronchiolitis. METHODS This two-arm randomized controlled trial included 146 children aged 3-24 months who were hospitalized with bronchiolitis at an Egyptian tertiary care center. Participants were equally randomized to receive a single intramuscular dose of 200000 IU (study group) or a daily oral dose of 400 IU (comparison group) of vitamin D3. The primary outcome was the time to hospital discharge. Secondary outcomes included time to oxygen weaning, discontinuation of intravenous fluids, and discharge readiness as well as serum 25-hydroxyvitamin D [25(OH)D] levels on day 3 post-randomization. Both the study and comparison groups were compared in the whole cohort (primary analysis) and within the subgroup of participants with baseline serum 25(OH)D levels < 30 ng/mL (prespecified subgroup analysis). RESULTS In the overall analysis, the study and comparison groups showed no significant differences in median time to discharge (130 hours vs 140 hours, P = 0.149) or in secondary outcomes, except for a higher serum 25(OH)D level in the study group (51 ± 12.8 vs 32 ± 13.2 ng/mL, P < 0.001). However, among the subgroup of participants with baseline serum 25(OH)D levels < 30 ng/mL, the study group demonstrated significantly shorter median times to hospital discharge (120 hours vs 170 hours, P < 0.001), oxygen weaning (56 hours vs 79 hours, P = 0.012), discontinuation of intravenous fluids (55 hours vs 73 hours, P = 0.017), and discharge readiness (118 hours vs 165 hours, P = 0.001) as well as a greater increase in serum 25(OH)D levels (40 ± 6.6 ng/mL vs 20 ± 6.1 ng/mL, P < 0.001) than the comparison group. CONCLUSION Vitamin D supplementation may improve clinical outcomes in hospitalized children with bronchiolitis who have vitamin D deficiency or insufficiency, supporting a test-and-treat approach.