Background: In light of widespread undertreatment for glucocorticoid- induced osteoporosis (GIOP), we designed a group randomized controlled trial to increase bone mineral density (BMD) testing and osteoporosis medication prescribing among patients receiving longterm glucocorticoid therapy. Methods: Using administrative databases of a large US health plan, we identified physicians who prescribed longterm glucocorticoid therapy to at least 3 patients. One hundred fifty-three participating physicians were randomized to receive a 3-module Web-based GIOP intervention or control course. Intervention modules focused on GIOP management and incorporated case-based continuing medical education and personalized audit and feedback of GIOP management compared with that of the top 10% of study physicians. In the year following the intervention, we compared rates of BMD testing and osteoporosis medication prescribing between intervention and control physicians. Results: Following the intervention, intent-to-treat analyses showed that 78 intervention physicians (472 patients) vs 75 control physicians (477 patients) had similar rates of BMD testing (19% vs 21%, P=.48; rate difference, ?2%; 95% confidence interval [CI], ?8% to 4%) and osteoporosis medication prescribing (32% vs 29%, P=.34; rate difference, 3%; 95% CI, ?3% to 9%). Among 45 physicians completing all modules (343 patients), intervention physicians had numerically but not significantly higher rates of BMD testing (26% vs 16%, P=.04; rate difference, 10%; 95% CI, 1%-20%) and bisphosphonate prescribing (24% vs 17%, P=.09; rate difference, 7%; 95% CI, ?1% to 16%) or met a combined end point of BMD testing or osteoporosis medication prescribing (54% vs 44%, P=.07; rate difference, 10%; 95% CI, ?1% to 21%) compared with control physicians. Conclusions: In the main analysis, a Web-based intervention incorporating performance audit and feedback and case-based continuing medical education had no significant effect on the quality of osteoporosis care. However, dose-response trends showed that physicians with greater exposure to the intervention had higher rates of GIOP management. New cost-effective modalities are needed to improve the quality of osteoporosis care. ©2007 American Medical Association. All rights reserved.