Pemphigus and osteoporosis: a case-control study.

OBJECTIVE To investigate the association between pemphigus and osteoporosis. DESIGN Case-control study. SETTING A large health care provider organization in Israel. PARTICIPANTS Patients with pemphigus older than 20 years (hereinafter, pemphigus patients) were compared with a sample of age- and sex-matched controls. Interventions  Data retrieval from a large community-based medical database regarding health-related lifestyles, comorbidities, use of medications, bone mineral density scans, and drugs for osteoporosis. MAIN OUTCOME MEASURES The prevalence of osteoporosis in patients and controls, use of bone mineral density scans, and drugs for osteoporosis. RESULTS The study included 255 pemphigus patients and 509 controls older than 20 years. Osteoporosis was diagnosed among 40.4% of pemphigus patients compared with 6.5% of controls (P < .001; odds ratio [OR], 9.77; 95% confidence interval [CI], 6.34-15.10). After controlling for confounders, including age, sex, and duration of glucocorticosteroid therapy and proton pump inhibitor therapy, the associations with osteoporosis persisted (OR, 4.27; 95% CI, 2.44-7.47; P < .001). Similar results were obtained when using cumulative glucocorticosteroid dose. Only 73 pemphigus patients with osteoporosis (70.9%) had undergone a bone mineral density test within the past 10 years. While most pemphigus patients with osteoporosis purchased medications for osteoporosis, including calcium (95.1% of patients), cholecalciferol (89.3%), bisphosphonates (90.3%), or raloxiphene (8.8%), the duration of therapy was short. CONCLUSIONS We found an association between pemphigus and osteoporosis, which persisted after controlling for glucocorticosteroid use. Monitoring and treatment of osteoporosis in pemphigus patients was suboptimal in this study.