Bone Loss in Inflammatory Rheumatic Musculoskeletal Disease Patients Treated With Low-Dose Glucocorticoids and Prevention by Anti-Osteoporosis Medications

Objective. The negative effects of glucocorticoids on bone depend on dose and treatment duration. However, it is unclear whether a safe dose exists, especially for patients with inflammatory rheumatic musculoskeletal diseases (iRMDs). We undertook this study to determine the effects of glucocorticoid doses on bone health in iRMD patients.Methods. We conducted a longitudinal cohort study on women with iRMD. Bone mineral density (BMD) and fractures were assessed prospectively and compared to a matched cohort without iRMD. Kaplan-Meier curves with log rank test were made for iRMD patients (stratified for glucocorticoid use and dose) and the matched cohort. Multivariable Cox regression survival models were also employed to analyze the effect of glucocorticoids on fracture.Results. A total of 884 women with iRMD and 1,766 controls (matched for age, T score, and 10-year fracture risk) were included in the study and followed up for up to 6 years. BMD decreased significantly in all patients receiving glucocorticoids who were not receiving anti-osteoporosis treatment (-4.26% for =5 mg/day of prednisone equivalent, P = 0.0011; -4.23% for 2.5-5 mg/day, P = 0.0422; -2.66% for 0-2.5 mg/day, P = 0.0006). Anti-osteoporosis treatment (largely bisphosphonates) prevented bone loss only in patients receiving <5 mg/day of prednisone equivalent. Fracture incidence was higher in patients with iRMD compared to controls, but only glucocorticoid doses =5 mg/day were associated with significantly higher risk of fracture.Conclusion. Glucocorticoid doses as low as 2.5 mg/day were associated with BMD loss in iRMD patients, but this effect was preventable. BMD loss in patients receiving =5 mg/day was not totally prevented by anti-osteoporosis medications currently used in clinical practice, resulting in higher risk of fracture.