RESUMEN
INTRODUCTION: Despite the availability of consensus guidelines for the treatment of vitamin D deficiency, prospective trials are lacking to examine alternative dosing strategies for adult patients with cystic fibrosis (CF) who do not meet therapeutic goals with standard regimens. OBJECTIVES: The primary objective of this study was to determine the efficacy of high-dose cholecalciferol supplementation in increasing serum vitamin D (25-OHD) levels in adult patients with CF. METHODS: Patients were eligible for inclusion if they were 18 years or older, had baseline 25-OHD levels lower than 30 ng/ml, and were diagnosed with CF and pancreatic insufficiency. Patients were given a single dose of cholecalciferol 300,000 or 500,000 IU based on baseline 25-OHD levels. Response was defined by 25-OHD and ionized calcium levels at 3 months. At 6 months, responders received a second dose of the same strength, and nonresponders were given a weekly supplement of cholecalciferol 50,000 IU in addition to cholecalciferol 500,000 IU. A second 25-OHD level was obtained at 9 months. RESULTS: Of the 46 patients enrolled, 32 patients (70%) completed the study. Baseline levels of 25-OHD significantly increased over time in the per protocol population at 3 and 9 months. A total of 16 patients (50%) were considered nonresponders and required weekly supplementation. CONCLUSION: A protocol using high-dose cholecalciferol or high-dose plus weekly cholecalciferol is safe and effective in treating adult patients with CF and pancreatic insufficiency.