Introduction: In recent years, guidelines for vitamin D supplementation have been updated and prophylactic recommended doses have been increased in patients with cystic fibrosis (CF).
Objective: To evaluate safety and efficacy of these new recommendations.
Results: Two cohorts of pancreatic insufficient CF patients were compared before (cohort 1: 179 patients) and after (cohort 2: 71 patients) American CF Foundation and European CF Society recommendations were published. Cohort 2 patients received higher Vitamin D doses: 1509 (1306-1711 95% CI) vs 1084 (983-1184 95% CI) IU/Day (p < 0.001), had higher 25 OH vitamin D levels: 30.6 (27.9-33.26 95% CI) vs. 27.4 (25.9-28.8 95% CI) ng/mL (p = 0.028), and had a lower prevalence of insufficient vitamin D levels (<30 ng/mL): 48% vs 65% (p = 0.011). Adjusted by confounding factors, patients in cohort 1 had a higher risk of vitamin D insufficiency: OR 2.23 (1.09-4.57 95% CI) (p = 0.028).
Conclusion: After the implementation of new guidelines, CF patients received higher doses of vitamin D and a risk of vitamin D insufficiency decreased. Despite this, almost a third of CF patients still do not reach sufficient serum calcidiol levels.
Keywords: cystic fibrosis; multicenter study; vitamin D.