The Zoster Vaccine Lowers More than Just Shingles Risk in Patients with Chronic Diseases
—According to these data, the risk of MI and stroke over 5 years in people vaccinated and not vaccinated, respectively, was 1.29% vs 1.82% and 1.61% vs 2.20% (p<0.05 for both MI and stroke comparisons).
Would your patients be amenable to a vaccine that reduced their risk for stroke or myocardial infarction (MI)? Oh, and also, shingles?
The annual incidence of herpes zoster (HZ; shingles), which is caused by the reactivation of latent varicella zoster virus (VZV), is about 1 million in the US. Older individuals, those taking immunosuppressive agents, and patients with chronic illness are most susceptible. According to the investigators of a study examining the relationship between the anti-HZ vaccine and the risk of stroke or MI in chronic disease, 95% of adults in the US carry the latent virus and are therefore susceptible to shingles. The symptoms of HZ typically last 2-4 weeks and the clinical presentation is characterized by a unilateral, itchy, and often painful rash across a specific band of skin related to the distribution of a specific dermatome. The investigators note that HZ reactivation has previously been linked to a subsequently increased risk for stroke and MI, especially in the first year after the eruption. But the impact of anti-HZ vaccination on the risk of stroke or MI specifically in those with chronic conditions has not previously been studied.
The current retrospective, population-based analysis evaluated a cohort of 27,093 adults vaccinated for shingles (61.23% female) and 135,465 unvaccinated matched (1:5) controls using the IBM MarketScan Commercial Claims and Encounters database from 2005-2018. The investigators evaluated the impact of live attenuated zoster vaccination on stroke and MI risk in adults indicated for vaccination—those 50 years and older (93.02% of both the vaccinated population and unvaccinated matched controls) or at high risk due to various chronic conditions (80.93% of vaccinated individuals; 75.09% of unvaccinated matched controls) —for exactly 5 years.
MI and stroke in vaccinated and unvaccinated individuals
The study investigators determined that, after controlling for age and sex, the risk of MI and stroke over 5 years in those who were vaccinated and not vaccinated, respectively, was 1.29% vs 1.82% and 1.61% vs 2.20% (p<0.05 for both MI and stroke comparisons).
- Patients with diabetes exhibited the greatest benefit with regards to reduced stroke risk from vaccination, with an odds ratio (OR) of 0.64 (0.58, 0.71).
- Those with the highest odds of stroke were patients with hypertension and chronic obstructive pulmonary disease (COPD). In these patients, significant risk reductions were also observed in those who were vaccinated. Specifically, the OR for stroke in those with hypertension was 0.75 (0.68,0.83) and the OR for stroke in those with COPD was 0.75 (0.68, 0.83).
The influence of comorbid conditions
Results for the impact of anti-HZ vaccination on MI risk in those with comorbidities was similar to the results for stroke risk in this population.
- Those vaccinated patients who had either diabetes or hypercholesterolemia had an OR of 0.63 for MI compared to unvaccinated individuals.
- Those with the highest MI odds still benefited from vaccination.
- Vaccinated patients with COPD had an OR of 0.74 versus the unvaccinated with COPD.
- Vaccinated patients with hypertension had an OR of 0.73 versus the unvaccinated with hypertension.
The number needed to treat (NNT) to prevent one MI was lowest for diabetes patients at 241, while other conditions ranged from 370 to 1162.
“There have been data for some time showing an increased risk of heart attack and stroke in patients following outbreaks of zoster (shingles),” says senior investigator, Galen T. Foulke, MD, Department of Dermatology, Penn State Milton S. Hershey Medical Center, Hershey PA. “We have repeated this finding, and in this study we have found a survival benefit across many common chronic diseases, regardless of the patient's age.”
Foulke says that the vaccine used in this study is no longer in use in the US and he would expect an even greater effect from the use of the currently available recombinant vaccine. “We performed this study using data from live attenuated vaccine for shingles, which is no longer available in the United States,” he said. “We did this because the recombinant vaccine is too new to have large quantities of data available for study. We predict a greater effect size from the new recombinant vaccine, but this needs to be studied directly, once more data are available.”
The impact of these findings, says Foulke, may not only be a reduction in strokes and heart attacks, but also a decrease in the associated costs. “From a public health perspective, an inexpensive vaccine could offer reduced population healthcare costs by reducing vascular complications of zoster such as heart attack and stroke.”
Caveats
Limitations of the study included its retrospective claims-based study design that relied on analysis of commercially insured individuals and therefore cannot be generalized to include patients on Medicaid, the uninsured or under-insured patient populations. The study also did not assess the severity of subsequent mortality from stroke or MI in this cohort. As noted, the impact of the recombinant vaccine could not be assessed since it only became available in October 2017. Additionally, the study could not control for socioeconomic factors and comprehensive data were unavailable for potential confounders including smoking, alcohol intake, and preventative medications. There was no time-to-event analysis performed and the study only controlled for age and sex.
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