Osteoporosis in steroid-dependent asthma

Background: Patients on prolonged corticosteroid therapy are at risk of developing osteoporosis. Some patients with severe asthma are difficult to wean off corticosteroids and are therefore at risk of developing bony complications due to steroids. Objective: The purpose of this study was to examine the relationship of cumulative steroid dosage and duration of therapy with osteoporosis. Methods: We obtained bone mineral density studies using dual photon absorptiometry, and radiographs of the lumbar spine of 16 steroid-dependent patients with asthma. Patients with conditions affecting bone metabolism were excluded. Results: We studied 16 male steroid-dependent patients with asthma who received 4 to 41 grams equivalent dose of prednisone over a period of 1 to 15 years. The overall prevalence rate for abnormal age-matched bone mineral density was 50%. Abnormal bone mineral density was more commonly noted in the lumbar spine (38%) than in the femoral neck (19%). The lowest dose of corticosteroid associated with a decrease in bone mineral density was a cumulative steroid dose of 5.6 equivalent grams-prednisone. Conclusion: Prolonged corticosteroid therapy can cause significant osteoporosis among male patients with steroid-dependent asthma. Bone loss due to corticosteroid therapy occurs at different rates at different bony sites.