(P-619) Venous Thromboembolism in Patients with Chronic Inflammatory Skin Diseases

Background: Given the increasing use of targeted immune-modulating treatments, including oral small molecules such as janus kinase inhibitors, in chronic inflammatory skin diseases (CISDs), there is a need to establish the background rate of newly occurring venous thromboembolism (VTE) events attributable to the skin disease. Existing studies have highly variable findings.

Objectives: To establish the incidence of VTE in patients with versus without a CISD.

Methods: We used commercial insurance claims data from a nationwide US healthcare database from 2004 through 2020. We identified 158,123 patients with at least 2 dermatologist-recorded diagnoses of a CISD (=cohort entry date), including: psoriasis (n=96,138), atopic dermatitis (n=30,418), alopecia areata (n=17,889), vitiligo (n=7,735) and hidradenitis suppurativa (HS) (n=5,934). We identified 1,570,387 patients without a CISD through 10:1 risk-set sampling, matched on calendar time (+/- 60 days). We excluded patients with prior VTE, anticoagulant use, cancer, pro-thrombotic conditions, sickle cell disease, HIV/AIDS, or other chronic inflammatory conditions. Follow-up lasted until the first of the following: VTE, death, disenrollment, or end of data. VTE events were identified with validated algorithms. 1:1 propensity-score (PS) matching accounted for VTE risk factor differences. Analyses were conducted using the Aetion Evidence Platform.

Results: The median follow-up time was 2 years. The incidence rate (per 1,000 person-years) of outpatient or inpatient VTE was 1.53 in CISDs overall, 1.57 in psoriasis, 1.83 in atopic dermatitis, 0.94 in alopecia areata, 0.93 in vitiligo, and 1.65 in HS compared to 1.76 in patients without a CISD. Incidence rates increased in patients aged 50+ (2.3 per 1,000 person-years) and decreased in those aged 18-49 (0.8 per 1,000 person-years). The incidence rates were almost unchanged when excluding patients who were receiving treatment with immunomodulatory drugs. After PS-matching, the hazard ratio of VTE comparing patients with CISD versus non-CISD was 0.94 (95% confidence interval: 0.84-1.05). In patients with psoriasis, it was 0.86 (0.75-0.99), in atopic dermatitis 1.19 (0.95-1.48), in alopecia areata 0.97 (0.65-1.46), in vitiligo 0.90 (0.49-1.65), and in HS 1.64 (0.82-3.27).

Conclusions: In this cohort study, chronic inflammatory skin diseases were not associated with increased incidence of VTE after controlling for relevant VTE risk factors and comorbidities among patients seen in dermatology practices.