Reliability of the hidradenitis suppurativa clinical response in the assessment of patients with hidradenitis suppurativa.

ABSTRACT

BACKGROUND: Hidradenitis suppurativa clinical response (HiSCR) is a validated clinical end point for measuring response to treatment in patients with hidradenitis suppurativa (HS). Previous studies have reported on the validity, responsiveness and meaningfulness of the HiSCR. OBJECTIVE: To evaluate the HiSCR for inter- and intrarater reliability characteristics. METHODS: A stand-alone, two-site, prospective, non-interventional observational study consisted of 22 patients, with self-reported severity between mild, moderate and severe HS. The Patient Global Impression of Change (PGI-C) scale was completed by patients at Timepoint 2. Descriptive statistics of Hurley Stage, total abscesses, total draining fistulas, total inflammatory nodules and total AN count (sum of inflammatory nodules and lesions) were reported at two timepoints. Inter-rater reliability and intrarater reliability for the HS lesion count tool were evaluated at two timepoints (baseline and Day 7) using the HS lesion count tool. Intraclass correlation (ICC) coefficients of lesion counts were calculated to evaluate inter- and intrarater reliability of lesion counts between pairs of dermatologists. RESULTS: The majority of patients demonstrated either no change or minimally worse PGI-C in HS scores. Descriptive statistics were similar between rater groups and timepoints assessed. Inter-rater ICC coefficients for abscess count at Timepoints 1 and 2 were 0.38 and 0.67. The ICC coefficients for draining fistula and AN count were ≥0.61 at both timepoints. In an exploratory model, ICC coefficients were ≥0.68 for all evaluated lesion counts. The test-retest reliability using ICC coefficients was ≥0.70 for total abscess, draining fistula, inflammatory nodule and AN count. CONCLUSION: The HS lesion count tool had an acceptable inter- and intrarater reliability, indicating that HiSCR has a strong degree of reproducibility and consistency in the evaluation of patients with HS.