P1238 Herpes Zoster Risk in Patients with Inflammatory Bowel Disease and Its Association with Medications Used: A Nationwide Population-Based Study in Taiwan
Authors: Tsai M J , Kuo T H , Lai H C , Wu Y H , Huang P J , Cheng K S , Chou J W 
Published: January 2025

Abstract

Background
Inflammatory bowel disease (IBD), encompassing Crohn’s disease (CD) and ulcerative colitis (UC), is an immune-mediated disease with lower prevalence in Taiwan. Herpes zoster (HZ) is thought to occur when immunity is weakened. This study aimed to evaluate the time-dependent risk of HZ in IBD patients and investigate the influence of medications used for IBD treatment on this risk.

Methods
A retrospective cohort and nested case-control study were conducted using administrative data from the Taiwan National Health Insurance Research Database, spanning 2000 to 2021. The index date for the IBD cohort was defined as the first recorded diagnosis of IBD. The non-IBD cohort included individuals without an IBD diagnosis, with a randomly assigned index date between 2000 and 2021. Propensity score matching at a 1:1 ratio was performed to match IBD and non-IBD cohorts based on age, sex, index year, comorbidities, and residence. The risk of HZ was assessed using incidence rates (IRs) and adjusted hazard ratios (aHRs). The association between prescribed medications and the risk of HZ in IBD patients was also evaluated.

Results
The study included 86,005 patients with IBD (CD: 67,934 patients; UC: 24,850 patients) and 86,005 non-IBD individuals. The risk of HZ in IBD patients was analyzed across different time intervals following diagnosis. IBD patients had an overall increased risk of HZ compared to non-IBD individuals. The risk was highest within the first year after diagnosis and gradually declined over time, reaching its lowest level after six years. Among the subtypes of IBD, CD patients consistently demonstrated the highest risk, with a peak between one and three years post-diagnosis and a sustained elevated risk across all time periods. In contrast, UC patients showed a significant increase in HZ risk within the first year and beyond six years. However, the risk for UC patients between one and six years post-diagnosis was not statistically significant (Table 1) . Medication analysis indicated that immunomodulators were independently associated with an increased risk of HZ. However, 5-aminosalicylic acids and biologic agents were not significantly associated with an increased risk of HZ (Table 2).

Conclusion
IBD patients face an elevated risk of HZ, particularly during the first year after diagnosis, with CD patients at the highest risk. Immunomodulators further exacerbate this risk. Vaccination should be considered at the time of IBD diagnosis to mitigate the risk of HZ.

References
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2.Côté-Daigneault J, Bessissow T, Nicolae MV, et al. Herpes Zoster Incidence in Inflammatory Bowel Disease Patients: A Population-Based Study. Inflamm Bowel Dis 2019;25:914-918.
3.Chang K, Lee HS, Kim YJ, et al. Increased Risk of Herpes Zoster Infection in Patients With Inflammatory Bowel Diseases in Korea. Clin Gastroenterol Hepatol 2018;16:1928-1936.e2.
4.Long MD, Martin C, Sandler RS, et al. Increased risk of herpes zoster among 108 604 patients with inflammatory bowel disease. Aliment Pharmacol Ther 2013;37:420-429.
Table 1: HZ Risk in IBD, UC, and CD Patients Over Time Since Diagnosis

Table 2: Impact of Different Medication Classes on the Risk of HZ in Patients with IBD