185 Fracture risk in adult and pediatric patients with atopic dermatitis -a population-based cohort study

Abstract

Atopic dermatitis (AD) is a chronic, relapsing skin disease associated with significant morbidities. Emerging evidence suggests that AD may be a risk factor for major fractures due to a decrease in bone mineral density resulting from concurrent chronic corticosteroid exposure and/or systemic inflammation. However, previous studies were limited by design and generalizability and pediatric data are scarce. We aimed to quantify the association between AD and fractures using a U.K. population-based electronic health records data from 1994 -2015. 625,083 adults and 409,431 children with AD were identified using a previously validated algorithm and matched on age, practice, and index date with 2,678,888 adult and 1,809,029 pediatric controls. Hazard ratios (HRs) were calculated using Cox regression and stratified by age and severity, which was defined as a time-updated variable using proxy measures of treatments and/or dermatologist referral. We found an overall small but increased fracture risk in children with AD aged 6-11 y (HR:1.07; 95% CI 1.04 -1.09) and 12-17y (HR: 1.04, 95% CI 1.00-1.07) compared to children without AD but no difference in risk among those aged <6 y (HR:1.00; 95% CI 0.98 -1.02). In children with severe AD, there was no difference in risk between AD and controls across all age groups. In comparison, select age groups of children with moderate (12-17 y HR:1.10; 95% CI 1.02 -1.18) and mild AD (6-11 y HR:1.07; 95% CI 1.05 -1.10) were more likely to develop fractures compared to controls. Among adults, those with AD had an increased overall risk of fractures versus controls (18-64 y HR:1.04; 95% CI 1.02 -1.05; ≥65y HR: 1.06, 95% CI 1.04-1.08). These associations were strongest among adults with severe AD (18-64 y HR:1.22; 95% CI 1.15 -1.29; ≥65y HR: 1.26, 95% CI 1.16-1.36). In summary, AD is associated with an overall small but increased risk of fractures, suggesting the need for additional research to establish biological plausibility.