Multimorbidity and atopic dermatitis in a population-based cohort: severity-dependent association with distinct...

Atopic dermatitis (AD) has characteristics of a systemic disease due to underlying systemic inflammation, which is supported by reports of various comorbidities.

To examine the associations between AD and (nonatopic) multimorbidity in a population-based cohort from the northern Netherlands and to identify differences in multimorbidity patterns between participants with multimorbidity and no AD.

We assessed the lifetime prevalence of 52 diseases, from 15 domains, combining data from questionnaires, medication records and clinical assessments within the Lifelines Cohort. Lifetime AD was self-reported, physician-diagnosed and disease severity based on the Patient-Oriented Eczema Measure. Multimorbidity was defined as the lifetime presence of at least two diseases, while nonatopic multimorbidity excluded asthma, rhinitis and food allergy. A composite morbidity score (cMS) indicated the degree of multimorbidity. We analysed associations of AD and AD severity with multimorbidity and cMS using binary and multinomial logistic regression, adjusting for age and sex, and additionally adjusting for socioeconomic and lifestyle factors. Patterns of nonatopic multimorbidity based on disease domains were explored using latent class analysis, stratified by AD presence.

Of 37 193 participants, 3242 (8.7%) had AD. The odds for nonatopic multimorbidity were 1.47-fold higher in participants with AD, particularly for those with moderate-to-severe disease (adjusted odds ratio 1.74 vs. 1.41 for mild disease). The association strengthened with higher degrees of nonatopic multimorbidity, reaching 2.09-fold for ≥ 5 diseases. When considering atopic diseases in the definition of multimorbidity and the cMS, the associations with AD were even stronger. Further adjustments for socioeconomic and lifestyle factors were corroborative. We identified five distinct multimorbidity classes among individuals with and without AD, with two differing across the groups. One class, characterized by the orofacial domain, was only present among those with AD, while another class - resembling the metabolic syndrome - had more of a respiratory contribution to AD with further differences regarding cardiometabolic involvement.

Participants with AD, especially moderate-to-severe disease, are more likely to experience (nonatopic) multimorbidity and showed unique patterns of nonatopic multimorbidity with regard to orofacial and cardiometabolic diseases. Our findings highlight the importance of promoting awareness for interdisciplinary approaches to managing patients with AD. An author video to accompany this article is available online.