Atopic Eczema-Associated Fracture Risk and Oral Corticosteroids: A Population-Based Cohort Study.

Abstract

Evidence suggests adults with atopic eczema have increased fracture risk. However, it is unclear whether oral corticosteroids explain the association. To assess to what extent oral corticosteroids mediate the relationship between atopic eczema and fractures. We conducted a cohort study using English primary care (Clinical Practice Research Datalink) and hospital admissions (Hospital Episode Statistics) records (1998-2016) including adults (18 years old and older) with atopic eczema matched (age, sex, and general practice) with up to 5 adults without atopic eczema. We used Cox regression to estimate hazard ratios (HRs) for specific major osteoporotic fractures (hip, spine, pelvis, or wrist) and for any-site fracture comparing individuals with atopic eczema with those without, adjusting for 6 different definitions of time-updated oral corticosteroid use (ever any prescription, ever high-dose, and recent, cumulative, current, or peak dose). We identified 526,808 individuals with atopic eczema and 2,569,030 without. We saw evidence of an association between atopic eczema and major osteoporotic fractures (eg, spine HR 1.15, 99% CI 1.08-1.22; hip HR 1.11, 99% CI 1.08-1.15) that remained after additionally adjusting for oral corticosteroids (eg, cumulative corticosteroid dose: spine HR 1.09, 99% CI 1.03-1.16; hip HR 1.09, 99% CI 1.06-1.12). Fracture rates were higher in people with severe atopic eczema than in people without even after adjusting for oral corticosteroids (eg, spine HR [99% CI]: confounder-adjusted 2.31 [1.91-2.81]; additionally adjusted for cumulative dose 1.71 [1.40-2.09]). Our findings suggest that little of the association between atopic eczema and major osteoporotic fractures is explained by oral corticosteroid use.