Association Between Inflammatory Bowel Disease and Hidradenitis Suppurativa: A Single-Center Retrospective Study

Background:
Studies have shown an association between inflammatory bowel disease (IBD) and hidradenitis suppurativa (HS), but there is conflicting data on whether it is more associated with Crohn’s disease (CD) versus ulcerative colitis (UC). In addition, the natural course and outcomes of patients with comorbid IBD and HS are unknown. The purpose of this study was to compare the clinical characteristics and disease course of patients with both IBD and HS compared with those of patients with isolated IBD or isolated HS.
Methods:
A retrospective chart review was conducted for patients who were seen at a single tertiary health system in New York City between 1/1/2016 and 5/31/2023. Of 970 patients diagnosed with HS by dermatologists, 35 had both confirmed IBD and HS. These patients were matched 1:1:1 with control cases having isolated IBD and isolated HS, based on age, sex, race, duration of the disease, and IBD type. Clinical variables related to HS and IBD were collected, including demographics, comorbid conditions, markers of disease severity, and treatment.
Results:
Of the 35 patients with both HS and IBD, 24 were female and 11 were male, with a median age of 34 years (range 14-81). Of patients with documented race, 16 were White (46%), 8 were Black (14%), and 5 were South Asian (23%). Six patients had UC, while 29 had CD. The median age at diagnosis of IBD was 19 (range 12-24) and of HS was 24 (range 20-36). IBD diagnosis preceded HS diagnosis in 26 patients, whereas HS preceded IBD in only 3 patients. When compared with the isolated IBD group, patients with comorbid CD and HS more often had perianal CD (55% vs 21%, p &#x3c; 0.01). When compared for IBD-related outcomes, there were more frequent IBD-related hospitalizations in the comorbid IBD and HS group (0.29 vs 1.38, <italic>P &#x3d;</italic> 0.02). The median number of biologics tried was 2 (<italic>P &#x3d;</italic> 0.7), and anti-TNF biologics were used in 32 patients (<italic>P &#x3d;</italic> 0.5). Combination therapy of biologics and immunomodulators was required in 13 patients (<italic>P &#x3d;</italic> 0.04). Intestinal surgical interventions were required in 14 patients (<italic>P &#x3d;</italic> 0.5). As for extraintestinal manifestation, peripheral arthritis had a significant difference between the comorbid group and the isolated IBD group (<italic>P &#x3d;</italic> 0.05). When compared for HS-related outcomes, the severity of HS assessed by the Hurley stage and the number of past surgical treatments did not significantly differ between the comorbid IBD and HS group and the isolated HS group.
Conclusions:
In this single-center study with a diverse population, there was a high proportion of South Asian patients. Patients with comorbid IBD and HS more often had CD than UC, and the proportion of patients with PFCD was higher than in the isolated IBD group. IBD exhibited more severe disease progression, necessitating more frequent combination therapy and hospitalizations, while HS severity was similar when compared with patients with isolated IBD or HS, respectively.