Getting to the Heart of the High-Risk Flu Population

Patients with cardiovascular disease are at the greatest risk for influenza-related mortality, yet flu vaccination rates among this population fall far below national vaccination targets. But a new University of Michigan Health System study has gotten to the heart of the problem and identified several ways to improve flu immunization rates for this high-risk group.

By simply making flu vaccine available in all cardiology offices and encouraging cardiologists to recommend vaccination for their patients, the study found immunization rates among non-elderly adults with cardiac disease could dramatically improve and approach the Healthy People 2010 goal of 60 percent vaccination coverage for the population at the highest risk for flu.

The results from this study currently appear on the Human Vaccines Web site, and results will appear in the journal later this month.

With approximately 12.5 million people, cardiac disease patients are the largest high-risk group of non-elderly adults in the United States recommended to receive flu vaccinations each year. However, a recent national study published by U-M and the Centers for Disease Control and Prevention (CDC) found that only about half of all cardiology practices in the country have flu vaccine on hand, making the effort to vaccinate this population more challenging, says study co-author Matthew M. Davis, MD, MAPP, assistant professor of pediatrics and general internal medicine at the U-M Health System, and assistant professor of public policy at the Gerald R. Ford School of Public Policy.

The answer to improving vaccination rates among this group is to make flu vaccine available in all cardiology offices and have cardiologists strongly recommend it, says Davis. He continues, Those interventions alone would improve vaccination rates for heart patients more than boosting community vaccinations at local pharmacies and grocery stores, increasing primary care vaccine availability, and trying to get all hospitalized patients vaccinated against flu. Most importantly, making vaccine available in the cardiology setting would be especially effective in situations of vaccine shortage.

For this study, Davis and co-author Satish Gopal, MD, a former UMHS medical resident who is now with the Department of Medicine at NorwalkHospital in Norwalk, Conn., used mathematical models to examine which interventions would be most effective at getting more non-elderly adults, ages 15 to 64, who have cardiac disease immunized against influenza.

The interventions studied included improvements in vaccine availability in cardiology practices, physician recommendation rates, performance of primary care and medical subspecialty practices, inpatient vaccination rates, patient acceptance, and community vaccination programs.

Assuming, under normal circumstances, that there was a sufficient supply of the flu vaccine available in a wide variety of settings, the overall vaccination coverage for this high-risk population was 36.3 percent, of which 65 percent of individuals were immunized within the healthcare system and 35 percent were immunized at community sites.

But when flu vaccine was available in all cardiology practices, the vaccine coverage for cardiac patients jumped to 41 percent. Similarly, when cardiologists strongly recommended flu vaccination to their patients, vaccine coverage grew to 37.4 percent.

What yielded the greatest results in cardiology practices was combining the two efforts, in conjunction with routine orders for nurses to vaccinate unless the patient had opted out. That effort, the study revealed, would lead to overall vaccine coverage of 45.7 percent, or about a 25 percent relative increase in the vaccination rate for non-elderly patients with cardiac disease.

If such interventions in cardiology practices were combined with additional efforts to maximize vaccination at other doctors offices, hospitals and in the community, the vaccination rate would likely reach 62.3 percent, exceeding the 60 percent vaccination coverage target set by Healthy People 2010, a set of health objectives for the nation to achieve over the first decade of the new century.

Even if a vaccination shortage were to occur, these combined interventions would still allow for a larger portion of non-elderly adult cardiac patients to be vaccinated again flu compared to current circumstances, Davis says.

Our model suggests that optimizing influenza vaccine delivery in cardiology practices would improve overall vaccination rates for this population, especially during flu vaccine shortages, explains Davis. I am encouraging patients with heart disease to ask their cardiologists to make flu vaccine available in their practices next year, if it is not available this flu season. But, adds Davis, to make the greatest impact on the national vaccination target set for non-elderly adults with cardiac disease, all interventions examined in this study need to be improved.

Reference: Human Vaccine, Vol. 1, No. 6.

Source: University of Michigan Health System