Incidence of anxiety disorder in adults with hidradenitis suppurativa.

Background: There are limited data on the risk of new-onset anxiety disorders in patients with hidradenitis suppurativa (HS).

Objectives: To compare the risk of new-onset anxiety disorder in patients with HS and controls, and to describe risk factors for the development of anxiety in patients with HS.

Methods: We carried out a retrospective cohort analysis of a US electronic health records database between 2011 and 2020. Adults newly diagnosed with HS at a dermatology or primary care visit and control participants were included. The primary outcome was a new diagnosis of generalized anxiety disorder, phobic disorders, panic disorder or unspecified anxiety. Cox proportional hazards regression was used to compare the crude risk of any anxiety disorder between groups and to assess the independent association with HS while controlling for potential demographic, clinical and healthcare-related confounders.

Results: Among 9597 patients with HS and 959 493 controls, the incidence rate (IR) of anxiety was 5.74 and 3.86 per 100 person-years (PY), respectively. The crude risk among all patients was 48% higher for those with HS vs. controls [hazard ratio (HR) 1.48, 95% confidence interval (CI) 1.40-1.55]. When stratified by index encounter type, patients with HS had 2.43 (95% CI 2.13-2.77) times the risk of anxiety disorder than dermatology controls and 1.46 (95%CI 1.38-1.55) times the risk than primary care controls. The adjusted HR for patients with HS vs. controls was 1.11 (95% CI 1.05-1.17) overall, 1.26 (95% CI 1.07-1.48) in the dermatology subgroup and 1.07 (95% CI 1.01-1.13) in the primary care subgroup. Risk factors for an incident anxiety diagnosis among patients with HS included depression (HR 1.69, 95% CI 1.48-1.93), female sex (HR 1.41, 95% CI 1.23-1.60), younger age (HR 0.87 per 10-year increase, 95% CI 0.84-0.90), White race, in the Medicaid insurance programme (HR 1.22, 95% CI 1.07-1.40), tobacco smoking (HR 1.16, 95% CI 1.03-1.31) and having one or more emergency department visits in the year before a HS diagnosis. Absolute IRs of anxiety disorders were highest among patients with HS who were aged 18-29 years (7.10 per 100 PY), female (6.34 per 100 PY) and White (6.79 per 100 PY).

Conclusions: HS is independently associated with an increased risk of anxiety disorders. An increased risk remains but is attenuated when confounders are controlled for. The relative risk may be particularly high in patients managed by dermatologists.