Cluster analysis identifies six clinical subtypes of hidradenitis suppurativa characterised by distinct comorbidities, inflammatory and metabolic profiles, patient-reported outcomes and treatment patterns

Background: Sub-classification of hidradenitis suppurativa (HS) may allow for a better understanding of disease aetiology and disease burden, and eventually permit a more personalised treatment for patients. Objective: To identify patient subtypes of HS based on comorbidity patterns and clinical characteristics, and to examine their inflammatory and metabolic blood profiles and associated levels of experienced distress, pain, quality of life, employment status and prescribed treatments. Methods: Cluster analysis of clinical data from consecutive, newly referred adult HS patients attending a dermatological hospital department. Results: A total of 534 patients (338 women and 196 men) with a mean age of 40.5 years (SD = 13.7) were included; 35.4% had Hurley stage I, 50.4% had Hurley stage II, and 14.8% had Hurley stage III. In total, six disease subtypes were identified: ‘female subtype’ (n = 182, 34.1%), ‘familial subtype’ (n = 144, 27.0%), ‘diabetes subtype’ (n = 107, 20.0%), ‘psychiatric disease subtype’ (n = 49, 9.2%), ‘Crohn's disease subtype’ (n = 29, 5.4%) and ‘asthma subtype’ (n = 23, 4.3%). Patients with ‘Crohn's disease subtype’ and ‘diabetes subtype’ had highest levels of systemic inflammation (C-reactive protein, erythrocyte sedimentation rate, leucocytes and neutrophils), blood glucose and lipids (triglycerides), p < 0.001. The highest boil-associated pain score, p < 0.001, overall disease-related distress, p = 0.008 and lowest quality of life, p = 0.015, was reported by patients with ‘familial subtype’, whereas highest rates of unemployment were observed among patients with ‘diabetes subtype’ and ‘psychiatric disease subtype’, p < 0.001. Treatment patterns differed significantly between the subtypes, with biologics being most often prescribed to patients with ‘Crohn's disease subtype’ (21.1%), p < 0.001. Conclusion: This study identified six subtypes of HS based on comorbidity patterns, clinical characteristics, blood profiles, patient-reported outcomes and treatment patters, supporting the concept of heterogeneity within HS.