Treatment of Low Bone Density in Cystic Fibrosis.

Overview

Cystic fibrosis (CF) -- an autosomal recessive genetic disease affecting about 60,000 individuals worldwide, including about 3,800 in Italy -- is often associated with low bone mineral mass. The current aggressive therapies have ensured a much longer survival of CF patients but this has led to a higher frequency of osteoporosis and bone fractures, a serious problem which not only affects quality of life, but also hinders further therapeutic measures. The aim of this study, conducted on a large group of children, adolescents and young adults with CF, has been the evaluation of bone mass changes after 1 year of a simple treatment with RDA-adjusted dietary calcium plus 25-OH vitamin D supplementation, and the feasibility and efficacy of alendronate treatment (for another year) in patients not responding to calcium + 25-OH vitamin D alone.

The study included 2 phases. Phase 1 (1-year open-label observational study): following baseline evaluation, bone mass changes have been studied with a simple therapy of adequate calcium intake and 25-OH vitamin D supplements in all eligible subjects (N=171). Phase 2 (1-year double-blind, randomized, placebo-controlled, parallel group study): the 128 subjects showing an insufficient response to calcium + 25-OH vitamin D alone (bone mass increase \<5%) at the end of Phase 1, were randomized into 2 groups and assigned to alendronate treatment (N=65) or placebo (N=63) (in addition to calcium and 25-OH vitamin D as during Phase 1). The study has been carried out by the Coordinator's Institution (Istituto Auxologico Italiano)in collaboration with most Regional Reference Centers for CF in Italy.