BACKGROUND: Quantification of disease severity supports the development of 
evidence-based treatments. Assessments to capture clinical improvement in 
hidradenitis suppurativa (HS) can be improved.
OBJECTIVES: This study aimed to validate the Hidradenitis Suppurativa Clinical 
Response (HiSCR), which is defined as a ≥ 50% reduction in inflammatory lesion 
count (sum of abscesses and inflammatory nodules, AN), and no increase in 
abscesses or draining fistulas in HS when compared with baseline as a meaningful 
clinical endpoint for HS treatment.
METHODS: Patients with ≥ 3 ANs at baseline in a Phase II adalimumab trial for HS 
were included for analysis. HiSCR achievers vs. nonachievers were assessed at 
week 16 and week 52. Criteria measures included physician-rated assessments 
[Hurley stage, modified Sartorius score (MSS), and HS Physician's Global 
Assessment] and patient-reported outcomes (PROs: visual analogue pain scale, 
Dermatology Life Quality Index, and Work Productivity and Activity Impairment 
questionnaire). Test-retest reliability, convergent validity, responsiveness and 
predictive validity of HiSCR, and its meaningfulness to patients were assessed.
RESULTS: Among 138 eligible study participants, the majority were female (69·6%) 
with a mean age of 36·7 years. The mean (median) MSS was 125·2 (85·5) at 
baseline. Test-retest reliability of the AN count was 0·91. HiSCR was 
significantly correlated with improvements in all physician-rated and PRO 
measures (Spearman's rho between -0·61 and -0·27, all P < 0·001). Improvements 
of all PROs in HiSCR achievers exceeded the respective meaningful improvement 
thresholds.
CONCLUSIONS: In patients with HS with ≥ 3 ANs, HiSCR achievers had significant 
improvements in physician-rated and patient-reported HS disease severity and 
impact. HiSCR is a valid and meaningful endpoint for assessing HS treatment 
effectiveness in controlling inflammatory manifestations in this population.