Increased risk of herpes zoster in patients with coeliac disease - nationwide cohort study

Background and aims: Clinical experience suggests that patients with coeliac disease (CD) are more prone to develop herpes zoster (HZ), but robust studies are lacking. Methods: We identified 29,064 patients with CD 1969-2008 using biopsy report data from Sweden's 28 pathology departments. CD was equalled to villous atrophy (Marsh histopathology grade III). Each patient was matched on age, sex, calendar year and county of residence to up to five reference individuals (n=144,342) from the general population. We then used Cox regression to estimate hazard ratios (HRs) for future HZ (defined as having a hospital-based inpatient or outpatient record of this diagnosis in the Swedish Patient Register). Results: During follow-up, 154 (0.53%) individuals with CD and 499 (0.35%) reference individuals developed HZ. Among individuals aged >= 60 years, 1.06% of CD individuals and 0.85% of reference individuals had a lifetime record of HZ. Overall, CD was associated with a 1.62-fold increased risk of HZ (95% CI=1.35-1.95), and was seen also when we considered comorbidity with lymphoproliferative disease, systemic lupus erythematosus, type 1 diabetes, thyroid disease, rheumatoid disease and excluded individuals with a record of dermatitis herpetiformis. The increased risk remained significant after more than five years of follow-up (1.46; 1.16-1.84) Conclusions: CD is associated with HZ, the increased relative risk persists over time from celiac diagnosis but the absolute risk is small.