Effect of oral bisphosphonates on bone mineral density and body composition in adult patients with cystic fibrosis: a pilot study

Background: Approximately two thirds of adult patients with cystic fibrosis have reduced bone mineral density and up to one quarter have osteoporosis at one or more sites. Any bone mineral deficits are likely to be exacerbated in patients following lung transplantation by their immunosuppressive regimen. Vertebral collapse and rib fractures will impair the ability to cough and the efficacy of physiotherapy treatments. Methods: Patients attending the Leeds Regional Adult Cystic Fibrosis Unit with either osteopenia or osteoporosis on dual energy x ray absorptiometry ( DXA) scanning were offered treatment with oral bisphosphonates after exclusion of abnormal vitamin D, calcium, or phosphate levels, abnormal thyroid function, or hypogonadism. Those declining treatment or patients with a normal initial DXA scan formed the control group. A second DXA scan was performed after a mean of 2.4 years in the treatment group and 2.9 years in the non-treatment group. Patients in the active group were asked to complete a short questionnaire detailing their adherence to treatment. Results: The medians of the differences in annual changes in bone parameters between treatment and control groups showed significant differences in bone mineralisation in favour of the treatment group at the lumbar spine (L2 - L4), the femoral neck, and for total body measurements. There were no significant differences in weight, height, or body composition in either patient group. Most treated patients stated that they adhered to treatment most of the time. Conclusion: Treatment with oral bisphosphonates may improve bone mineralisation in adult patients with cystic fibrosis. The results of this pilot study need to be further explored in a randomised controlled trial.