The bisphosphonate alendronate is an oral anti-resorptive agent that is commonly used to treat osteoporosis. To date, its greatest success has been for use in postmenopausal women, men > 65 years of age, and patients with corticosteroid-induced osteoporosis. Improvements in BMD range from 2 to 6%, which are considered clinically important and are statistically significant when compared to BMD changes in the control arm of randomized trials. Other smaller, nonrandomized studies and one RCT have also confirmed the benefit of therapy with bisphosphonates in treating CF-related bone loss. RCTs of IV bisphosphonates also have demonstrated significant BMD improvements in CF participants; however, a common treatment side effect is infusion-related bone pain. As a result, oral bisphosphonates are considered to be first-line therapy for those persons who are identified to be at risk in this population.
In our study, we examined therapy with alendronate, 70 mg once weekly, and found clinically significant improvements in BMD over 12 months. Compared with the control group, the alendronate group had 4.04% greater BMD gain at the lumbar spine and 3.03% greater BMD gain at the total hip even after controlling for other variables. We did not have the power to properly examine new vertebral fractures. Two patients in the control group and none in the treatment group experienced a new vertebral fracture after the baseline measurement.