Splenectomy associated with increased risk of herpes zoster in a population-based cohort study

Background/Objective: No systematic research focuses on the association between splenectomy and herpes zoster. This study aimed to investigate the association between splenectomy and herpes zoster in Taiwan. Methods: A population-based cohort study was conducted using the database of Taiwan National Health Insurance Program. There were 640 individuals aged 20-84 years who were newly diagnosed with splenectomy in 2000-2012 as the splenectomy group and 2546 sex-matched and age-matched individuals without splenectomy as the nonsplenectomy group. The incidence of herpes zoster at the end of 2013 was estimated. The multivariable Cox proportional hazards regression model was used to estimate the hazard ratio and 95% confidence interval (CI) for herpes zoster associated with splenectomy. Results: The overall incidence of herpes zoster was 1.41-fold higher in the splenectomy group than in the nonsplenectomy group (11.3 vs. 8.05 per 1000 person-years, 95% CI 1.11-1.78). After multivariable adjustments, the adjusted hazard ratio of herpes zoster was 1.57 for individuals with splenectomy (95% CI 1.08-2.29), compared with individuals without splenectomy. Conclusion: Individuals with splenectomy are associated with 1.57-fold increased risk for developing herpes zoster in Taiwan. Vaccination against herpes zoster may be considered among these high-risk individuals.