Severe mental illness among adults with atopic eczema or psoriasis: UK population-based matched cohort studies

Conference:

SAPC ASM 2022 - UCLan

Talk Code:

5C.6

Presenter:

Elizabeth Adesanya

Co-authors:

Alasdair Henderson, Julian Matthewman, Ketaki Bhate, Joseph Hayes, Amy Mulick, Rohini Mathur, Catherine Smith, Helena Carreira, Sujit D Rathod, Sinéad M Langan, Kathryn E Mansfield

Author institutions:

London School of Hygiene & Tropical Medicine, University College London, Guys and St Thomas' Foundation Trust and King's College London

Problem

Existing research exploring the association between atopic eczema or psoriasis, and severe mental illness (i.e., schizophrenia, bipolar disorder, and other psychotic disorders) is limited. Longitudinal evidence for the association is particularly scarce, especially in adults, therefore the direction of the relationship between atopic eczema or psoriasis and severe mental illness is unclear. We aimed to investigate the effect of atopic eczema or psoriasis on the risk of incident severe mental illness among adults in the UK.

Approach

We conducted matched cohort studies using primary care electronic health data collected between January 1997 and January 2020 from the UK Clinical Practice Research Datalink. We identified two cohorts: one including adults (18 years) with and without atopic eczema, and one including adults with and without psoriasis. Adults with atopic eczema or psoriasis were identified using validated algorithms and matched on age, sex, and general practice with up to five adults without atopic eczema or psoriasis. We used Cox regression stratified by matched set to estimate hazard ratios (HRs) comparing the risk of incident severe mental illness in adults with and without atopic eczema or psoriasis. We initially constructed crude models including only the main exposure variable (atopic eczema or psoriasis) and implicitly adjusted for matching variables. In sequential models we adjusted for potential confounders (socioeconomic deprivation, calendar period) and then additionally adjusted for potential mediators (comorbidities, harmful alcohol use, smoking status and body mass index, and, in atopic eczema only, problems with sleep and high-dose glucocorticoid use).

Findings

We identified 1,023,232 adults with atopic eczema matched to 4,908,059 without, and 363,210 adults with psoriasis matched to 1,801,875 without. Median follow up was 5.2 years (IQR 2.0-10.2) in the atopic eczema cohort and 6.0 years (IQR 2.4-11.6) in the psoriasis cohort. After adjusting for potential confounders, both atopic eczema and psoriasis were associated with at least a 17% increased risk of severe mental illness (atopic eczema: HR 1.17, 95% CI 1.12-1.22; psoriasis: HR 1.26, 95% CI 1.18-1.35). Additionally adjusting for potential mediators attenuated severe mental illness risk in both cohorts (atopic eczema: HR 1.01, 95% CI 0.96-1.07; psoriasis: HR 1.13, 95% CI 1.04-1.22).

Consequences

Our findings suggest adults with atopic eczema or psoriasis are at increased risk of severe mental illness compared to adults without atopic eczema or psoriasis, although this increased risk may be explained by mediating factors (i.e., problems with sleep or lifestyle factors). This research highlights the potential importance of monitoring mental health status in adults with atopic eczema or psoriasis. Future studies should aim to identify specific modifiable factors that could be targeted to reduce severe mental illness in adults with atopic eczema or psoriasis.

Submitted by:

Elizabeth Adesanya

Funding acknowledgement:

EA was funded by a British Skin Foundation (BSF) PhD studentship (Reference: 024/S/18). SML was supported by a Wellcome Trust Senior Research Fellowship in Clinical Science (205039/Z/16/Z).