Mapping risks of health conditions in people with atopic eczema in English primary care and hospital data.

Atopic eczema may be associated with multiple health conditions. Here, we systematically explore risks across the full health spectrum based on the International Classification of Diseases, assessing associations between eczema and 2058 ICD-10 codes, 1593 phecodes, and 201 Global Burden of Disease codes. In English primary care electronic health records (1997 - 2023) we identify cohorts of people with eczema (up to 3 million) and matched (by age, sex, general practice) comparators without eczema (up to 14 million). In up to 25 years of follow-up, we capture outcomes recorded during hospital admissions. People with eczema show higher rates of several outcomes across multiple organ systems. Among those followed up from eczema diagnosis in childhood, atopic/allergic conditions and infections account for most excess diagnoses. Consistent across cohorts and analyses, large relative risk increases are seen for inflammatory bowel conditions (e.g., K50 Crohn disease, crude hazard ratio 1.70 [1.63-1.77]) and eye diseases (e.g., H16 Keratitis, crude hazard ratio 1.71 [1.57-1.86]). We provide a dashboard to explore and browse the full range of results.