Fracture risks in patients with atopic dermatitis: a nationwide matched cohort study.

Background The risk of osteoporosis has been explored in atopic dermatitis (AD). The long-term risk of fractures in AD patients and the effects of various AD treatment on bone health remain to be elucidated. Objective To examine the long-term risk of fractures in AD patients. Methods This nationwide matched cohort study was conducted using the Taiwan's National Health Insurance Research Database, for the period 1997 to 2013. A total of 36,855 AD patients and 147,420 reference subjects without AD were identified. Demographic characteristics and comorbidities were compared, and cumulative incidence of fractures was examined. Adjusted hazard ratios for fracture risks of AD and various AD treatment were calculated using Cox proportional hazard model. Results: A total of 1,518 patients (4.12%) in the AD cohort and 5,579 patients (3.78%) in the reference cohort had fractures (p=.003). The mean ages were 22.6 years in both groups. The 16-year cumulative incidence of fractures in the AD cohort (8.043%) was significantly higher than that in the reference cohort (7.366%) (p=.002). Severe AD (adjusted hazard ratio [aHR] 1.31, 95% confidence interval [CI] 1.08-1.59) was independently associated with fractures. Other independent risk factors included exposure to topical (aHR 1.21, 95% CI 1.05-1.39) or systemic corticosteroids (≥10 mg/day, aHR 1.62, 95% CI 1.38-1.91). Use of disease modifying antirheumatic drugs (aHR 0.71, 95% CI 0.53-0.90) and phototherapy (aHR 0.73, 95% CI 0.56-0.95) were associated with a lower risk of fractures. The results were consistent across sensitivity analyses. Conclusion AD patients have a higher incidence of fractures. Severe AD is independently associated with fractures.