Background/Objectives: Caucasian and Asian patients with Hidradenitis Suppurativa (HS) demonstrate significant differences with regards to age, sex and body mass index. What remains unknown is the impact of ethnicity upon the efficacy of therapeutics once demographic and disease characteristics has been taken into account. This is an important question given the expansion of biologic therapies for HS into the global patient community.
Methods: A retrospective analysis from a single HS specialist centre in Australia. The primary endpoint examined was the rate of primary response at 16 weeks, as measured by HiSCR50 and IHS4-55, as well as time to loss-of-response; stratified by patient-identified ethnicity in those identifying as either Caucasian or Asian.
Results: 170 patients with HS were identified (61 Asian; 36%). Asian patients demonstrated significantly lower BMI, higher rates of smoking and greater odds of Hurley stage 3 disease with tunnels compared to Caucasian patients. There was no significant difference between percentage of individuals achieving HiSCR50 or IHS4-55 at Week 16 between ethnicity subgroups.
Significant differences were seen in median time to secondary loss of response between Caucasian and Asian patients (105 versus 47 weeks, P = 0.003), and Kaplan-Meier analysis showed a significant difference in time to loss of response when stratified by patient-reported ethnicity for IHS4-55 but not HiSCR50. Multivariate Cox regression analysis demonstrated that, after accounting for age, gender, BMI, smoking and Hurley stage, ethnicity is not a significant influence on time to secondary loss-of-response (Hazard Ratio 1.05, P = 0.87).
Conclusions: Differences in treatment response to Adalimumab exist between Caucasian and Asian HS patients, however these differences can be accounted for by known demographic and disease variables.