OBJECTIVE: To determine longitudinal patterns and predictors for the utilization of bone mass measurements and anti-osteoporotic medications in the prevention of glucocorticoid-induced osteoporosis. METHODS: Within a managed care population of 7 million persons, we identified 3,125 adult men and women who had initiated longterm glucocorticoid therapy (>or=7.5 mg/day of prednisone equivalent for > 6 mo). The study population was examined by 3 biennial intervals between years 1996 and 2001 for receipt of a bone mass measurement and use of anti-osteoporotic medication (bisphosphonate, calcitonin, raloxifene, hormone replacement therapy). RESULTS: Receipt of a bone mass measurement increased among postmenopausal women from 10% in 1996-97 to 19% in 2000-01, but remained below 6% in all biennial intervals among women under age 50 and men. The use of anti-osteoporotic medication was most common among postmenopausal women, where it approached 50%. The largest absolute increase in anti-osteoporotic medication utilization was among women ages 65 and over, increasing from 24% in 1996-97 to 44% in 2000-01. The specialty of physician providing care was associated with receipt of both testing and treatment. Odds of receipt of a bone mass measurement and anti-osteoporotic medication were 3 to 4 times greater among patients of rheumatologists compared to those of internists or family practitioners. CONCLUSION: Among patients initiating longterm glucocorticoid therapy, the proportion of individuals receiving a bone mass measurement or anti-osteoporotic medication remains relatively low, but has improved temporally among postmenopausal women.