Herpes zoster may be an independent risk factor for vascular disease

Herpes zoster was an independent risk factor for vascular disease, particularly in subjects affected before age 40, a study found.

The retrospective population cohort study looked at 106,601 herpes zoster cases from among 3.6 million active patients collected over 23.7 years. These were matched 1:2 to 213,202 controls by age, sex and general practice from the THIN (The Health Improvement Network) general practice database in the United Kingdom.

Researchers looked at the risks of stroke, transient ischemic attack (TIA), and myocardial infarction (MI), and then adjusted for vascular risk factors such as body mass index, smoking, cholesterol, hypertension, diabetes, ischemic heart disease and atrial fibrillation, among other conditions, for up to 24 years (median, 6.3 years) after herpes zoster occurred.

Results were published ahead of print on Jan. 2 by Neurology.

Risk factors for vascular disease were significantly increased in the patients with herpes zoster compared with controls. For TIA, the adjusted hazard ratio (AHR) was 1.15 (95% CI, 1.09 to 1.21) and for MI it was 1.10 (95% CI, 1.05 to 1.16). For stroke, the AHR was 1.02 (95% CI, 0.98 to 1.07).

The increases in risk were particularly large in cases where herpes zoster occurred in patients under 40 years old: The AHRs were 2.42 for stroke (95% CI, 1.34 to 4.36), 1.49 for TIA (95% CI, 1.04 to 2.15) and 1.74 for MI (95% CI, 1.13 to 2.66). The researchers noted that patients under 40 were significantly less likely to be asked about vascular risk factors than were older patients (P<0.001).

The researchers noted that irrespective of age, conditions that predispose to vascular disease, including lifestyle factors such as smoking and obesity, were significantly more common in the patients with herpes zoster, although that finding may also have resulted from better recording of risk factors in this population. In older patients, better ascertainment of vascular risk factors and earlier intervention could have explained the lower stroke risk after herpes zoster.

“Overall, these data add to the growing body of evidence linking VZV [varicella zoster virus], a ubiquitous pathogen that establishes persistent infection in more than 95% of individuals, to vascular disease,” the researchers wrote. “Immunization with the licensed zoster vaccine has been shown to significantly reduce the incidence of herpes zoster as well as significantly decrease the severity of neuropathic complications. Population studies are now needed to evaluate whether immunization to prevent herpes zoster could also reduce the incidence of vascular events including stroke, TIA and MI.”