OBJECTIVES: Hidradenitis suppurativa (HS) is a chronic, inflammatory skin disease that affects up to 1% of the population in Europe. The EQ-5D-3L is the most commonly used generic instrument for measuring health-related quality of life among HS patients. Little is known about the performance of the newer, five-level version of the questionnaire (EQ-5D-5L) in this patient population. This study aims to compare the measurement properties of the two adult versions of EQ-5D (3L and 5L) in patients with HS.

METHODS: Between September 2017 and October 2019, we carried out a cross-sectional survey at three academic dermatology clinics in Hungary. We recruited 200 consecutive patients with HS to participate in the study. Patients completed the 3L, 5L, Dermatology Life Quality Index (DLQI) and Skindex-16.

RESULTS: Overall 62% of the patients were male, and the mean age was 37 years. More than twice as many different health state profiles occurred in the 5L compared to the 3L (101 vs 43). Ceiling effects slightly decreased from 16.0% (3L) to 14.6% (5L). A good agreement was established between the 3L and 5L with an of ICC 0.872 (95% CI 0.830-0.903; p<0.001) that was confirmed by using a Bland-Altman plot. The 5L improved the absolute discriminatory power (Shannon’s index) of the questionnaire in all dimensions. The 5L correlated stronger with both the DLQI and Skindex-16 in 3/5 dimensions, and was able to discriminate better between known groups of patients based on education level, smoking status, body mass index, disease severity and treatments.

CONCLUSIONS: In patients with HS, the 5L outperformed the 3L in feasibility, ceiling effects, discriminatory power, convergent and know-groups validity. We recommend using the 5L version of the EQ-5D in HS patients across various settings, including clinical care, research and economic evaluations.