SEX-BASED DIFFERENCES IN DRUG DURABILITY AMONG PATIENTS WITH INFLAMMATORY BOWEL DISEASES

Abstract

Abstract BACKGROUND With an increasing number of therapeutic options to treat IBD, identification of patient-specific factors predictive of drug efficacy is crucial. Sex has been postulated to play a role in response to therapy with possible proposed mechanisms including sex-based hormones and microbiome and epigenetic differences. However, prior clinical data on drug durability stratified by sex are mixed and limited. METHODS Using the SPARC IBD (Study of a Prospective Adult Research Cohort with Inflammatory Bowel Disease) registry, we analyzed time to drug discontinuation for female versus male patients started on a new IBD medication (including biologic and small molecule therapy) after enrollment between 2016 and August 2022. Drug persistence was examined using Kaplan-Meier plots. A Cox regression model was used to adjust for baseline differences in Crohn’s disease phenotype, rates of perianal disease, and concurrent immunomodulator use. A marginal means/rates model was used to adjust for within-patient correlation given that 252 patients had multiple medication starts. RESULTS A total of 1185 patients were identified with 1492 unique new medication starts (n=830 female, 662 male). In this sample, male patients had more complex Crohn’s disease phenotype and higher rates of perianal disease and concurrent immunomodulator use. No significant difference was seen in 12 month drug therapy survival rates based on sex (67.5% females, 65.7% males). Median drug continuation time was 33.5 months in females (95% CI 25.8, 37.4) and 24.5 months in males (95% CI 20.3, 32.8). No difference was seen in anti-TNF and small molecule subgroup analyses. Cox model adjusted for baseline differences in disease severity showed no significant different in probability of drug discontinuation per unit time in females compared to males [HR (95% CI) = 0.95 (0.75-1.21)]. CONCLUSION Both males and females have similar rates of IBD drug durability over time. The reasons for drug discontinuation should be explored in further studies as this may aid physicians in clinical decision-making.