Risk of severe herpes zoster infection in patients with polycystic kidney disease: A nation‐wide cohort study with propensity score matching analysis

Background Polycystic kidney disease (PKD) is suggested to be likely associated with underlying immunological dysregulation. This lymphopenia poses a risk of viral infection. Data to elucidate the herpes virus infection risk in patients with PKD are lacking; therefore, we conducted a national‐wide population‐based cohort study to investigate the herpes virus risk in PKD patients. Methods From the Taiwan National Health Insurance Research Database (NHIRD), patients who were hospitalised with a diagnosis of polycystic kidney disease were defined as case group of PKD patients; patients without any diagnosis of PKD during the study period were grouped into the non‐PKD cohort. The index date was set as the date when the patients were newly diagnosed with PKD. All study patients were followed up until the occurrence of herpes zoster infection, death, withdrawal from the NHIRD for other reasons, or until December 31, 2013. Results We included 4366 PKD patients and 4366 non‐PKD patients. The incidence rate and the risk of developing herpes zoster infection were estimated using multivariate stratified analyses. PKD patients had a 1.97‐fold risk of herpes zoster virus infection (aHR = 1.97, 95% CI 1.17‐3.31) compared with the non‐PKD cohort. On multilayer stratification, PKD patients without any comorbidities had a significantly increased risk of herpes zoster infection (aHR = 3.10, 95% CI 1.37‐7.00). Conclusion This is the first study to reveal a high risk of severe herpes zoster infection in patients with PKD. High index suspicion of severe herpes zoster infection should be maintained in clinical professionals.