A Novel Version of the IHS4 Tool for Hidradenitis Suppurativa Developed

A novel dichotomous IHS4 version, based on a 55% reduction of the total score, was developed.

A dichotomous version of the continuous International Hidradenitis Suppurativa Severity Score System (IHS4) tool was found to perform similarly to the Hidradenitis Suppurativa Clinical Response (HiSCR) instrument and discriminate between treated and untreated patients with hidradenitis suppurativa (HS). These findings were described in a study published in Journal of the European Academy of Dermatology & Venereology.

Investigators from the European Hidradenitis Suppurativa Foundation sourced data from the PIONEER-I and -II trials for this study. The dichotomous IHS4 tool was developed using 8 potential IHS4 thresholds. The most effective threshold for discriminating between patients with HS who received adalimumab or placebo at week 12 was evaluated.

In PIONEER-I and -II, 144 and 149 patients received adalimumab, and 145 and 140 received placebo, respectively. Patient groups were mean age 34.9-38.1 years, 59.0% to 70.0% were women, 43.6% to 49.0% were Hurley stage III, they had 8.7 to 11.6 inflammatory nodules, 3.1 to 4.6 draining tunnels, 2.1 to 2.9 abscesses, and IHS4 score was 26.1% to 35.3%, respectively.

Using correlation matrices between potential IHS4 cutoffs (30%, 50%, 55%, 60%, 65%, 70%, 75%, 80%) and HiSCR scores, the best cutoff was 55%, researchers found. The IHS4-55 tool discriminated between adalimumab and placebo recipients in PIONEER-I (odds ratio [OR], 2.00; 95% CI, 1.26-3.18; P =.003) and PIONEER-II (OR, 2.79; 95% CI, 1.76-4.43; P <.001) trials.

The novel IHS4-55 performs similarly to the current gold standard of HiSCR.

In PIONEER-II, 61% of IHS4-55 achievers and 60% of HiSCR achievers received adalimumab compared with 30% of IHS4-55 achievers and 29% of HiSCR achievers among the placebo group.

Stratified by achieving IHS4-55, in the combined dataset achievers had a greater reduction in the number of inflammatory nodules (mean, 6.89 vs 0.61; P <.001), draining tunnels (mean, 2.12 vs -0.79; P <.001), abscesses (mean, 1.86 vs 0.16; P <.001), and C-reactive protein (mean, 4.25 vs 0.49 mg/L; P <.001) compared with nonachievers, respectively.

Similar findings were observed in the subgroup analysis which stratified patients on the basis of Hurley stage.

This dichotomous tool may not be useful for other therapies, it was acknowledged.

Study authors concluded that “the novel IHS4-55 performs similarly to the current gold standard of HiSCR,” and is correlated with lesion reduction, and could discriminate between adalimumab and placebo recipients. They elaborated, “the fact that the continuous IHS4 is based on standard lesion counts and the use of the continuous IHS4 as a secondary endpoint in many ongoing clinical trials has already paved the way for implementation of the new dichotomous IHS4-55 as a secondary and future primary outcome.”

Disclosure: Several authors declared affiliations with industry. Please refer to the original article for a full list of disclosures.


Tzellos T, van Straalen KR, Kyrgidis A, et al. Development and validation of IHS4-55, an IHS4 dichotomous outcome to assess treatment effect for hidradenitis suppurativa. J Eur Acad Dermatol Venereol. Published online October 2, 2022. doi:10.1111/jdv.18632