Increased risk of varicella zoster virus infection in inflammatory bowel disease in an Asian population: a nationwide population-based cohort study

Purpose: Whether patients with inflammatory bowel disease (IBD) exhibit a high risk of developing varicella zoster virus (VZV) infection in Asian populations remains inconclusive. We investigated the causal relationship between two diseases by analysing the Taiwan National Health Insurance Research Database.

Patients and methods: Based on a universal insurance claims database, we enrolled 7055 IBD patients and 28,220 age- and sex-matched controls. We calculated the hazard ratios (HRs) and 95% confidence intervals (CIs) of the herpes zoster virus (HZV) in the IBD and comparison cohorts, using the Cox proportional hazards regression model.

Results: Patients with IBD exhibited significantly higher risk of the HZV compared with the controls (adjusted HRs, 1.42; 95% CI, 1.27-1.60). Further analysis indicated that male patients (adjusted HRs, 1.61; 95% CI, 1.35-1.92), aged 35-44 (adjusted HRs, 1.47; 95% CI, 1.08-2.01) and aged 65 years and older (adjusted HRs, 1.47; 95% CI, 1.19-1.80), and patients without comorbidities (adjusted HRs, 1.44; 95% CI, 1.26-1.66), exhibited excessive risks of VZV infection. Moreover, our findings show that the overall risk of developing VZV infection increased risk from 1.03 (95% CI, 0.90-1.18) (≤ 2 visits) to 9.76 (95% CI, 7.60-12.5) (> 4 visits), which correlates positively with the frequency of medical visits (trend test p < 0.0001).

Conclusion: Patients with IBD, particularly men aged 35-44/65 years and over, and patients without comorbidities, are associated with a long-term risk of VZV infection. The excessive risk of VZV infection should be considered for administering vaccines to IBD patients.