Relationship of psoriatic arthritis with nail and scalp involvement in Turkish psoriasis patients: Multicentered cross-sectional study

Psoriasis is a common multisystem inflammatory disease, and arthritis is an essential component of the disorder, requiring early diagnosis and prompt treatment for successful management. In this study, we aimed to investigate the relationship between nail and scalp involvement and other covariates with psoriatic arthritis (PsA). This cross-sectional study, conducted from June 2021 through December 2021, included 763 patients from 11 different centers in Turkey. The severity of involvement was evaluated using psoriasis area severity index (PASI), nail psoriasis severity index (NAPSI), and psoriasis scalp severity index (PSSI) scores. Predictors for PsA were evaluated using univariate and multivariate logistic regression models. PsA (n = 155, 21.5%) was significantly more common in patients having a family history of psoriasis (43.2% vs 30.9%, P = .004), nail involvement (68.4% vs 52.3%, P < .001), and coexistence of nail and scalp involvement (53.7% vs 39.6%, P = .002). Furthermore, patients with PsA had considerably higher PASI (7 vs 5.6, P = .006), NAPSI (5 vs 2, P < .001), and PSSI scores (7 vs 4, P = .002) and longer disease duration (months) (126 vs 108, P = .009). In multivariate analysis, female gender [OR: 3.01, 95% CI (1.861–4.880), P < .001], nail involvement [OR: 2.06, 95% CI (1.293–3.302), P = .002)], and body mass index (BMI) [OR: 1.06, 95% CI (1.017–1.100), P = .005] were identified as independent predictors for PsA. Female gender, nail involvement, and high BMI are significant predictors for PsA and warrant detailed rheumatological assessment. Notably, being female is the strongest predictor of increased risk of PsA in our survey. Scalp involvement appears not to be associated with PsA. Also, the presence of PsA seems related to a more severe skin involvement phenotype.