RESUMEN
CONTEXT: In 2012, The North American Cystic Fibrosis Foundation (NACFF) published new guidelines for the treatment of vitamin D deficiency in individuals with cystic fibrosis (CF). OBJECTIVE: The objectives of our study were to assess the efficacy of these guidelines, and to test the effect of increasing vitamin D dosage on pulmonary function and exacerbations. DESIGN: Pulmonary function tests and serum concentrations of 25-hydroxyvitamin D [25(OH)D] were measured 1 year before increasing vitamin D dosage according to the guidelines and at least 1 year later. In addition, days of hospitalization and pulmonary exacerbations were counted and an average per year (average number of days of hospitalization and average number of pulmonary exacerbations [PEA], respectively) was calculated. SETTING AND PARTICIPANTS: A total of 90 patients from The Cystic Fibrosis Clinic at Hadassah Mount-Scopus Hospital, Jerusalem, Israel. RESULTS: The mean serum concentration of vitamin D increased significantly from 20.97âng/mL (52.34ânmol/L) at baseline to 25.41âng/mL (63.42ânmol/L) at the end of follow-up (Pâ<â0.001). The number of PEA decreased significantly from 2.79â±â3.96 to 2.15â±â2.91 (Pâ=â0.007). The change in vitamin D levels was correlated with a decrease in PEA (correlation coefficientâ=â-0.318, Pâ=â0.002). CONCLUSIONS: The NACFF guidelines for management of vitamin D deficiency improve vitamin D levels in patients with CF but did not reach the normal values in most patients. The increase in vitamin D serum levels was, however, associated with a decrease in number of pulmonary exacerbations.