rapid vs maintenance vitamin d supplementation in deficient children with asthma to prevent exacerbations.

Conditions: Asthma; Vitamin D Deficiency

Summary: the role of vitamin d in respiratory health remains uncertain. whether vitamin d reduces clinically important exacerbations of childhood asthma remains uncertain. we compared rapid to maintenance vitamin d repletion analyzed by baseline vitamin d level.

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.

Eligibility criteria:
inclusion criteria: * children 2-14 years of age with moderate to severe asthma and proved to be vitamin d deficient by serum level. exclusion criteria: * prematurity (gestational age 34 weeks or less) * patients on vitamin d therapy * patients on seizure medication or diuretics * patients on chronic steroid use for other reasons than asthma * patient with chronic liver or kidney disease * patients with inherited bone disease * patients with hypo or hyper parathyroidism * patients with history of chronic lung disease other than asthma

Keywords: allergy clinical trial exacerbation pediatrics