Incidence and risk factors for herpes zoster among patients with inflammatory bowel disease

Background & Aims: An increased risk of herpes zoster in patients with inflammatory bowel disease (IBD) is hypothesized based on altered immune function, especially among patients receiving immunosuppressive medications. Methods: We performed a retrospective cohort study and a retrospective nested case-control study using 1988-1997 data from the General Practice Research Database. In the cohort study, 7823 Crohn's disease (CD) and 11,930 ulcerative colitis (UC) patients were matched on age, sex, and primary care practice to 79,563 randomly selected controls without CD or UC. In the nested case-control study, 185 CD patients with zoster and 266 UC patients with zoster were matched on sex and year of birth to 1787 IBD patients without zoster. Results: In the cohort study, the incidence of zoster was higher in patients with CD and UC compared with their matched controls (UC incidence rate ratio, 1.21; 95% confidence interval [CI], 1.05-1.40; CD incidence rate ratio, 1.61; 95% CI, 1.35-1.92). In the nested case-control study, receipt of a prescription for corticosteroids (adjusted odds ratio, 1.5; 95% CI, 1.1-2.2) or azathioprine/6-mercaptopurine (adjusted odds ratio, 3.1; 95% CI, 1.7-5.6) were both associated with zoster. Conclusions: Patients with IBD, especially those on immunosuppressive medications, are at higher risk for herpes zoster compared with the general population. Future studies should clarify the relative risk associated with anti-tumor necrosis factor a therapies and determine the use of the new zoster vaccine for patients with IBD.