Rapid vs Maintenance Vitamin D Supplementation in Deficient Children With Asthma to Prevent Exacerbations.

Recently published Cochrane metaanalysis suggested that vitamin D reduces the risk of severe asthma exacerbations, but only 22 children contributed to that analysis from a study that found no difference in acute care visits or rescue steroid administration. Altogether, randomized trials performed in children show promise solely in meta-analyses that use varied clinical outcomes and analysis approaches.

Were vitamin D supplementation beneficial for children with asthma, it might prevent moderate to severe asthma exacerbations entirely in some children, reduce the overall frequency of exacerbations in a treated group, or both. To examine these possibilities, we designed a randomized explanatory study comparing rapid vs maintenance vitamin D supplementation for children with moderate-to-severe asthma and with low baseline vitamin D levels .

Children presenting to the ED with moderate-to-severe asthma exacerbations and vitamin D levels < 25 ng/mL underwent masked randomization, and then open dosing to either IM+oral (the latter daily) therapy or daily oral-only therapy, and were followed for 12 months.The primary outcome was patient-initiated unplanned visits for asthma exacerbations,examined two ways: cumulative proportions with an exacerbation, and average exacerbation frequency. As this was a nutrient study, we analyzed treatment groups by quartile of baseline vitamin D level, collecting repeat levels and clinical observations at 3, 6, 9,and 12 months after enrollment.

One hundred and sixteen patients in the IM+oral cohort vs 115 in the oral-only cohort had similar mean (SD) baseline levels: 15.1 (5.4) vs 15.8 (5.2) ng/mL (range, 3-25 ng/mL). There was no difference in the primary outcome over the entire 12-month observation period. However, rapid IM+oral supplementation significantly reduced unplanned visits for asthma exacerbations for children with baseline levels of 3 to 11 ng/mL during the initial 3 months: the relative exacerbation rate for the IM+oral cohort compared with the oral-only cohort at 3 months was 0.48 (95% CI, 0.28-0.89; P ¼ .008); average exacerbation frequency per child analysis, relative rate 0.36 (95% CI, 0.13-0.87; P ¼ .017).

So Rapid compared to maintenance vitamin D supplementation for children with the lowest levels resulted in short- but not long-term reduction in asthma exacerbations.