OBJECTIVES: The Hidradenitis Suppurativa (HS) Quality of Life (QOL) Questionnaire (HiSQOL) provides a valid, reliable assessment of HS patients’ health-related QOL, an area where instruments are lacking. To guide interpretation, we determined the clinically meaningful within-patient (CMWP) improvement and severity thresholds for HiSQOL total and subscale scores for patients with moderate to severe HS.

METHODS: Pooled, blinded data from two identically designed, randomised phase 3 trials, BE HEARD I&II (NCT04242446, NCT04242498), of bimekizumab 320 mg every two/four weeks or placebo, were used to estimate HiSQOL score thresholds. The 17-item total score (range 0–68) and three subscale scores were evaluated: symptoms (0–16), psychosocial (0–20) and activities-adaptations (0–32). Higher scores indicate higher symptomology/impact. Threshold analyses were conducted on observed scores for all randomised patients with ≥1 non-missing HiSQOL subscale score at any scheduled assessment visit. Anchor- (Patient Global Impression of HS Severity [PGI-S-HS]) and distribution-based analyses were used to determine CMWP improvement thresholds. Receiver operating characteristic analyses (PGI-S-HS anchor) were used for severity thresholds.

RESULTS: The analysis set included 1,010 patients. For the 17-item HiSQOL total score, a 20- to 21-point decrease was identified as a marked CMWP improvement. For HiSQOL subscales, the following CMWP improvement thresholds were identified: symptoms: 5- to 6-point decrease; psychosocial: 4- to 5‑point decrease; activities-adaptations: 10- to 11-point decrease.

Severity thresholds for the HiSQOL total score were identified: 0–4, 5–14, 15–21, 22–23 and ≥24 for None, Mild, Moderate, Severe and Very Severe, respectively. Severity thresholds for HiSQOL subscales: symptoms: 0–2, 3–4, 5–6, 7 and ≥8; psychosocial: 0, 1, 2, 3–5 and ≥6; activities‑adaptations: 0–1, 2–4, 5–8, 9–12 and ≥13, for None, Mild, Moderate, Severe and Very Severe, respectively.

CONCLUSIONS: This analysis defined CMWP improvement and severity thresholds for HiSQOL total and subscale scores, which can be used to assess treatment effects on disease burden in patients with HS.