There is an association between higher rates of Crohn’s disease (CD) in pediatric patients with hidradenitis suppurativa (HS) compared to those without HS, according to new findings, although Crohn’s disease is still known to be rare.¹

The research was authored by Amit Garg, MD, from the Department of Dermatology at the Donald and Barbara Zucker School of Medicine. Garg and colleagues noted that Crohn disease and HS are recurrent inflammatory disorders which are chronic and have shared genetic susceptibility and certain shared immunologic elements.²

“Population-based studies have found an association between CD and HS in adults; however, this association is poorly characterized among pediatric patients,” Garg and colleagues wrote. “Herein we compared the prevalence of CD among pediatric patients with and without HS.”

Background and Findings

The investigators used deidentified data from the IBM Explorys database in their study, which contained electronic health records from over 40 healthcare networks in the US. The research team focused on individuals between the ages of 12 - 17 who had at least 2 reported medical encounters and 6 months of observation between January 1, 2015, and December 31, 2019.

The team randomly selected the patients in their control group out of those without HS and using a 15% sample size, ensuring the participants met the age and medical follow-up criteria. The study was deemed exempt from approval by the Northwell Health Institutional Review Board due to data de-identification.

The investigators determined the primary outcome to be the diagnosis of Crohn's disease on or prior to December 31, 2019, using a minimum of 2 International Classification of Diseases (ICD)-9 or ICD-10 codes. Unadjusted and adjusted log-binomial regression models were used by the team to assess the crude association between HS and CD while accounting for potential confounding factors such as ethnicity, age, medicaid insurance status, sex, race, body mass index, smoking status, and number of healthcare meetings.

A subgroup analysis aimed at those aged 15 - 17 years was conducted by the research team as this group comprised the majority of the study’s participants. The data were analyzed from December 6, 2022, to March 31, 2023.

A total of 2883 pediatric patients with a diagnosis of HS, as well as a median age of 17 years, was included by the research team in their study. The group also was 83% female and 17% male. The team also added 222,186 control patients with a median age of 16 years, made up of 52% females and 48% males.

The investigators reported that the prevalence of Crohn's disease was shown to be 0.69% among individuals with HS and 0.17% among those in the control arm, resulting in an unadjusted prevalence ratio of 4.11 (95% CI: 2.63 - 6.44).

After the research team’s adjusted analysis, the prevalence ratio for Crohn’s in those with HS was found to be 4.90 (95% CI: 3.07 - 7.84; P < .001) compared to the control arm. Among patients aged 15 - 17 years, the prevalence of Crohn’s was found to be 0.73% in those with HS and 0.20% in control patients, resulting in an unadjusted prevalence ratio of 3.61 (95% CI: 2.25 - 5.81).

After adjusting for the covariates, the investigators found that the prevalence ratio of Crohn’s disease was 4.84 (95% CI: 2.95 - 7.96; P < .001) among HS patients in the age range of 15 - 17 years compared to control patients in the same age range.

“Findings of this study suggest an association between CD and HS in pediatric patients,” they wrote. “However, the low absolute prevalence of CD in this group is reassuring and should be taken into context when counseling patients.”

References

1. ^{Mastacouris N, Strunk A, Garg A. Prevalence of Crohn Disease Among Pediatric Patients With Hidradenitis Suppurativa. JAMA Dermatol. Published online June 14, 2023. doi:10.1001/jamadermatol.2023.1585.}
2. ^{Garg A, Hundal J, Strunk A. Overall and subgroup prevalence of Crohn disease among patients with hidradenitis suppurativa: a population-based analysis in the United States. JAMA Dermatol. 2018;154(7):814-818. doi:10.1001/jamadermatol.2018.0878.}