Background and aims.
Patients with inflammatory bowel disease (IBD) are at an increased risk for vaccine-preventable diseases, such as herpes zoster (HZ). The aim of this study was to determine whether complications of HZ are more frequent in patients with IBD than in non-IBD controls.

Methods
This was a retrospective, cohort study using the Optum Research Database. Patients with IBD were matched 1:1 to non-IBD controls based on age, sex, and index year, which was defined as the diagnosis of HZ. We then identified the complications of HZ that occurred up to 90 days after the index date. We compared patients with IBD with non-IBD controls and evaluated the 90-day risk of HZ complications (Figure 1). We used a composite primary outcome for any HZ complication. Secondary outcomes were risk factors for complications.

Results
Four thousand seven hundred fifty-six patients with IBD met the inclusion criteria and were matched to the controls (Table 1). Patients with IBD were more likely to have complications of HZ than controls [800 (16.82%) vs. 624 (13.12%), p < 0.0001]. The most frequent complications included: Hospitalization due to HZ (OR 2.4, 95% CI 1.8-3.2), post herpetic neuralgia (OR 1.3, 95% CI 1.1-1.6), neurological complications (OR 1.5, 95% CI 1.2-1.9) and disseminated zoster (OR 3.8, 95% CI 1.4-10) compared to non-IBD controls (Table 2). Patients with IBD with higher comorbidity scores were more likely to develop complications (1.97 vs. 1.14 p < 0.0001). The most frequent complication of HZ was PHN in the IBD cohort [286 (6.01%) and ophthalmic complications in the non-IBD cohort (238 (5.00%)]. In the logistic regression analysis of patients with IBD having congestive heart failure, history of cancer, above 50 years of age and on treatment with anti-TNF or corticosteroids were all at increased risk of a complication from HZ (Table 4).

Conclusion
Patients with IBD are more likely to have complications of HZ than controls. Efforts are needed to increase HZ vaccine uptake to reduce the morbidity of HZ. Gastroenterologists have an opportunity to improve care and reduce the burden of HZ-related complications in patients with IBD by identifying those at increased risk and vaccinating patients.

<b>Figure 1. Flowdiagram of Patients with IBD and non-IBD controls.</b><br /> Using the Optum Research Database, we obtained data from January 1st, 2007, through April 1st, 2022, of patients with at least 12 months of baseline coverage and up to three months after index date of HZV diagnosis. A total of 1,660,773 patients with HZV were identified from which 622,445 met the criteria above. IBD cases were defined as prior IBD related visits between 2007 and 2022 and outpatient pharmacy claims for IBD related treatments. Cases were matched by age, sex, and by index year to non-IBD controls. The matching algorithm described produced 4,756 patients in each group.

Figure 1. Flowdiagram of Patients with IBD and non-IBD controls.
Using the Optum Research Database, we obtained data from January 1st, 2007, through April 1st, 2022, of patients with at least 12 months of baseline coverage and up to three months after index date of HZV diagnosis. A total of 1,660,773 patients with HZV were identified from which 622,445 met the criteria above. IBD cases were defined as prior IBD related visits between 2007 and 2022 and outpatient pharmacy claims for IBD related treatments. Cases were matched by age, sex, and by index year to non-IBD controls. The matching algorithm described produced 4,756 patients in each group.

Tables:<br /> Table 1: Baseline Characteristics of the cohort in IBD and Non-IBD controls<br /> Table 2: Complications of Herpes Zoster in patients with IBD and non-IBD controls within 90 days of index case.<br /> Table 3: Predictors for complications of HZV among Patients with Inflammatory Bowel Disease.<br /> Table 4: Multivariable Analysis of Predictors for Complications1 related to Herpes Zoster

Tables:
Table 1: Baseline Characteristics of the cohort in IBD and Non-IBD controls
Table 2: Complications of Herpes Zoster in patients with IBD and non-IBD controls within 90 days of index case.
Table 3: Predictors for complications of HZV among Patients with Inflammatory Bowel Disease.
Table 4: Multivariable Analysis of Predictors for Complications1 related to Herpes Zoster