Background: Limited data are available on the characteristics of patients with different types of psoriasis. ICD-10-CM codes, the first version classifying psoriasis types, became effective in 2015 in the US.
Objectives: To describe characteristics of adult psoriasis patients by type.
Methods: A retrospective cohort study was conducted in the Optum™ Market Clarity Data. Adult (18+ years) patients with psoriasis were eligible for inclusion if they had ≥1 ICD10 code for psoriasis in Optum claims and linked EHR during 01Oct2015-31Dec2021, had ≥365 day of enrollment before the first psoriasis diagnosis (index) date during the period. These patients were classified into plaque (ICD10 L40.0), guttate (L40.4), pustular (L40.1), palmoplantar (L40.3, L40.2), flexural and other specified (L40.8), and unspecified psoriasis (L40.9) based on the index diagnosis. Comorbidities or medical histories were defined using two diagnoses codes at baseline. Standardized mean difference ≥0.1 was applied for differences among cohorts. Odds ratios and 95% CI from logistic regressions were used to assess the association between psoriasis types and medical history while controlling for demographics, with plaque psoriasis as the reference.
Results: A total of 50,287 patients with psoriasis (age 52.9 ±15.5 years, women 55.4%) were included, of whom 27,810 were unspecified; for the remainder (22,477, 44.7% of 50,287) there were 15,278 plaque (68.0%), 1119 guttate (5.0%), 383 pustular (1.7%), 911 palmoplantar (4.1%), 4,786 other specified (21.3%) psoriasis. Compared with patients with plaque psoriasis, patients with pustular psoriasis were older (53.8±14.8 vs 51.7±14.9 years) and had more women (66.8% vs 54.2%), diabetes (15.9% vs 12.9%), hyperlipidemia (25.8% vs 22.7%), and skin infections (13.4% vs 8.9%); patients with palmoplantar psoriasis were also older (57.2±13.8 years) and had more women (76.1%), diabetes (16.4%), hyperlipidemia (31.6%), skin infections (19.3%), inflammatory bowel disease (2.9% vs 1.5%) and malignancy (7.8% vs 4.9%); patients with guttate psoriasis were younger (44.6±16.2 years), had lower diabetes (8.7%), hyperlipidemia (14.6%), and malignancy (2.4%). Compared with plaque psoriasis, palmoplantar (OR 2.13, 1.76-2.58) and pustular psoriasis (OR 1.52, 1.09-2.11) were associated with a higher risk for skin infections; palmoplantar psoriasis was associated with a higher risk for malignancy (OR 1.34, 1.02-1.77), when controlling for demographics.
Conclusions: Plaque psoriasis is the most common type, followed by guttate and palmoplantar psoriasis. Patients with different types of psoriasis have different clinical characteristics, even after controlling for demographics.
