HERPES ZOSTER LINKED TO VASCULAR EVENTS

More evidence links herpes zoster (HZ) with vascular disease events.

A new study shows HZ to be an independent risk factor for transient ischemic attack (TIA) and myocardial infarction (MI) in all adults up to 24 years after an acute episode, and for stroke as well, although only among people whose HZ occurred when they were under 40 years of age.

"The messages from this study are that people who are found to have risk factors for vascular disease should be vaccinated to prevent herpes zoster, which in itself is a severe disease, and that people who have herpes zoster may be at increased risk for stroke," said lead study author Judith Breuer, MD, professor, virology, University College, London, United Kingdom (UK).

It's not clear yet whether the vaccine will prevent stroke, "although we think that it might," said Dr. Breuer.

The study is published online January 2 in Neurology. The research was supported by the National Institute for Health Research, University College London Hospitals Biomedical Research Centre, and Sanofi Pasteur MSD, the European maker of the herpes zoster vaccine.

No Stroke Signal

Researchers used The Health Improvement Network (THIN) primary care database, which includes information on more than 3 million patients and is representative of the UK population. The analysis included 106,601 cases of HZ as well as 213,202 controls (2 for every case) who did not have a record of HZ and were matched for age, sex, and general practice.

To reduce miscoding, the study excluded recurrent HZ, which can be confused with herpes simplex.

After adjustment for sex, age, obesity, smoking status, history of elevated cholesterol, hypertension, diabetes, ischemic heart disease, atrial fibrillation, intermittent arterial claudication, carotid stenosis, and valvular heart disease, the study showed a 15% increased risk for TIA and a 10% increased risk for MI associated with HZ.

TIA itself was a risk factor for stroke, increasing the incidence 7-fold compared with age-matched controls (14.32% vs 2.07%).

However, the analysis showed no significant difference in stroke risk for cases compared with controls.

"We found an association for MI and for TIA, which is a form of stroke, but we didn't find a signal for stroke; it was slightly more common in people who had herpes zoster, but not significantly so," said Dr. Breuer.

Table 1. Risk for Vascular Events With Herpes Zoster, Adjusted for Vascular Risk Factors

Endpoint	Adjusted Hazard Ratio (95% Confidence Interval)	P Value
TIA	1.15 (1.09 - 1.21)	<.05
MI	1.10 (1.05 - 1.16)	<.05
Stroke	1.02 (0.98 - 1.07)	NS
NS = not significant.

This lack of statistical association may have been due to the fact that the study looked at events occurring more than a year after the acute HZ episode. Dr. Breuer pointed to another study from Denmarkpublished this past summer on July 17 that looked at the "immediate aftermath" and did find that herpes zoster was a short-term risk factor for stroke, although it looked at stroke and TIA together.

However, stroke, as well as TIA and MI, was significantly increased in those whose HZ occurred when they were younger adults, between ages 18 and 40 years.

Table 2. Risk for Vascular Events With Herpes Zoster Occurring at Ages 18 to 40 Years

Endpoint	Adjusted Hazard Ratio (95% Confidence Interval)	P Value
TIA	2.42 (1.34 - 4.36)	<.05
MI	1.49 (1.04 - 2.15)	<.05
Stroke	1.74 (1.13 - 2.66)	<.05