Reciprocal relationship between herpes zoster and cardiovascular diseases: A nationwide population‐based case–control study in Korea

Recently, herpes zoster (HZ) has been identified as a risk factor for stroke, but there have been few studies on the relationship between HZ and other cardiovascular diseases (CVD), including myocardial infarction (MI) and heart failure (HF). The purpose of this study was to investigate the risk of HZ occurrence after CVD and the occurrence of CVD after HZ. This was a retrospective case-control study based on the National Health Insurance System claims database for 20 311 patients with HZ and 13 980 patients with CVD and 1:5 age- and sex-matched control subjects for each from January 2006 to December 2013. We evaluated the reciprocal relationship between HZ and CVD including MI, ischemic stroke and HF. Severe HZ requiring hospitalization independently increased the risk of subsequent MI (hazard ratio [HR], 1.831; 95% confidence interval [CI], 1.354-2.476)], ischemic stroke (HR, 1.523; 95% CI, 1.212-1.915) and HF (HR, 2.034; 95% CI, 1.615-2.562) during the study period. Likewise, patients with an episode of MI, ischemic stroke or HF were also at increased risk of HZ hospitalization (after MI: HR, 1.625; 95% CI, 1.144-2.308; after stroke: HR, 1.518; 95% CI, 1.177-1.957; and after HF: HR, 1.485, 95% CI 1.041-2.117). Our results suggest that there is a significant reciprocal relationship between severe HZ requiring hospitalization and CVD including MI, ischemic stroke and HF.