Herpes zoster infection raised the risk of stroke by 35% and of myocardial infarction by 59%, in a South Korean nationwide study.
In addition, the risks of stroke and MI were highest in the first year following herpes zoster infection and decreased over time, said Min-Chul Kim, MD, the University of Ulsan, Seoul, South Korea, and associates.
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They studied the association between herpes zoster and cardiovascular risks using a Korean health care database covering the entire country’s population, focusing on 519,880 adults who received a medical checkup during a 10-year period. A total of 23,233 (4%) of these patients were diagnosed as having herpes zoster infection and were propensity score–matched with the same number of control subjects who didn’t have the infection. Both groups were then followed for the development of stroke or MI.
The incidence of stroke was 1.34 per 1,000 person-years higher among patients with the infection than among those without it. Similarly, the incidence of MI was 0.80 per 1,000 person-years higher among patients with the infection than among those without it. The risks of both stroke and MI were highest during the first year after herpes onset and decreased over time. In contrast, the risks of stroke and MI were evenly distributed over time in the control group, the investigators said in a letter to the editor (J Am Coll Cardiol. 2017;70:293-300). Several possible reasons have been proposed to explain a causal association between this infection and cardiovascular disease. Herpes zoster is “the only virus for which there is clear evidence of viral DNA and antigen in areas of ischemia or infarction in cerebral arteries,” Dr. Kim and associates noted.
Viral replication adjacent to a cerebral or cardiac artery could cause inflammation of the vessel, followed by subsequent thrombosis and rupture. Or, repeated subclinical reactivation of the virus could weaken the arteries. It is also possible that herpes zoster reactivation alters patients’ immunologic status, making them vulnerable to cerebrovascular or cardiovascular events, the investigators said.
This study was supported by the Korea Health Technology Research and Development Project, the Korea Health Industry Development Institute, and the Republic of Korea Ministry of Health & Welfare. Dr. Kim and associates reported having no relevant financial disclosures.