Body composition of hidradenitis suppurativa compared to psoriasis and healthy controls.

BACKGROUND: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease frequently associated with metabolic alterations. Conventional methods of measurement, such as BMI, do not adequately capture these differences in body composition. OBJECTIVES: To assess body composition in HS using bioimpedance analysis, compare findings with psoriasis and healthy controls and explore HS phenotypes based on metabolic and clinical profiles. METHODS: In this cross-sectional study, body composition was measured using the InBody 770. HS severity was assessed using Hurley staging and IHS4. K-means clustering was applied to identify HS subtypes. RESULTS: The study included 109 HS patients, 106 psoriasis patients and 106 healthy controls. HS patients had a significantly higher BMI than psoriasis patients and controls (median 32.3 vs. 28.6 and 27.0 kg/m2; both p < 0.001). Body fat mass was also highest in HS (36.0 kg vs. 26.6 kg and 24.5 kg; p < 0.001), as was visceral fat area (171.8 cm2 vs. 130.6 cm2 and 114.0 cm2; p < 0.01). After multivariable adjustment, HS remained associated with increased adiposity, including higher body fat mass, percentage body fat, visceral fat area and obesity degree compared with both control groups. Lower physical activity was significantly associated with higher IHS4 scores (p = 0.030). Multivariable adjustment showed no significant association between Hurley stage or IHS4 and body composition parameters (p > 0.05). CONCLUSIONS: HS showed a markedly altered body composition, with higher BMI, body fat mass and visceral fat area than both psoriasis patients and healthy controls. These findings support the use of bioelectrical impedance analysis as an additional clinical tool beyond BMI to better characterize metabolic risk in HS.