Osteoporosis in corticosteroid-treated asthmatic patients: clinical correlates.

This study sought to identify clinical and laboratory characteristics associated with the development of osteoporosis in 44 corticosteroid (CS)-treated asthmatic patients. Percentage predicted bone density was inversely correlated with both the duration of CS therapy (r = -.39, p = 0.009) and 24-hour urine calcium excretion (chi 2 = 5.2, p = 0.022). Bone density was not related to prednisone equivalent dose, alternate day versus daily therapy or serum cortisol levels. These data suggest that (1) long duration of CS therapy and increased urine calcium may identify patients at increased risk of developing CS-induced osteoporosis, and (2) urinary loss of calcium may be of particular importance in the pathogenesis of this condition.