Flu vaccine could lower chances of heart attack and cardiac arrest, particularly in high-risk patients: Study

Flu vaccination in high-risk patients was associated with a 28% reduced risk of heart attack, 85% lower risk of cardiac arrest, 73% reduced risk of death and 47% lower risk of mini-strokes

                            Flu vaccine could lower chances of heart attack and cardiac arrest, particularly in high-risk patients: Study
(Getty Images)

The rate of seasonal flu vaccinations among high-risk groups such as people over 50 and nursing home residents is extremely low, but those who do get their flu shot significantly lower their cardiovascular risks for heart attack, transient ischemic attack (often called a mini-stroke), death and cardiac arrest, according to preliminary research.

Of more than 7M high-risk patients hospitalized in the US, researchers found that those adults (aged 50 and over) who were vaccinated had better outcomes in the year following vaccination, with an 85% lower risk of cardiac arrest, a 28% lower risk of heart attack, a 73% lower risk of death and a 47% lower risk of transient ischemic attack. The findings, which indicate that the flu vaccine could protect against serious heart and stroke complications, will be presented at the virtual American Heart Association's Basic Cardiovascular Sciences 2020 Scientific Sessions, from July 27-30.

"High-risk groups benefited with flu vaccination and had reduced risk of myocardial infarction (MI), mortality, transient ischemic attacks (TIA), and cardiac arrest. Flu vaccination was paradoxically underutilized in the high-risk patients and when used was associated with reduced rates of MI, transient ischemic attack, and cardiac arrest in all high-risk cohorts compared to those who did not receive a vaccination. These results underscore the need for healthcare policy initiatives to optimize flu vaccination among all patients and especially among high-risk groups identified by the US Centers for Disease Control and Prevention (CDC)," say researchers from the Texas Tech University Health Sciences Center. 

The stress that influenza infection puts on the body may increase the risk of having a heart attack or stroke, which researchers note is well known. Several groups are considered at high risk for influenza and its complications. "These groups should have the highest vaccination rates because they are the most at risk. However, our findings show the opposite, flu vaccinations are under-utilized. As healthcare providers, we must do everything we can to ensure our most vulnerable populations are protected against the flu and its serious complications," says Roshni A Mandania, lead author of the study and MD candidate (class of 2021) at Texas Tech University Health Sciences Center Paul L Foster School of Medicine in El Paso, Texas. 

The stress that influenza infection puts on the body may increase the risk of having a heart attack or stroke, say experts (Getty Images)

Using information from the 2014 National Inpatient Sample (NIS), the largest database of US hospitals, researchers assessed the rate at which the flu vaccine was administered to patients designated by the CDC as high-risk for the flu and its complications. The database includes people over age 50, HIV/AIDS patients, those residing in nursing homes, and people who are obese. Researchers examined the impact of the flu vaccine on cardiovascular outcomes between patients who got vaccinated during hospitalization and those who did not.

“Our retrospective cohort study compared utilization and outcomes in high-risk groups among those who did receive vaccination during hospitalization versus those who did not. We analyzed utilization and impact of flu vaccine in several high-risk groups identified by CDC, that is, adults 50 years and older, people with chronic medical conditions, AIDS patients, people at nursing facilities, American Indians and Alaskan natives, and obese people in the 2014 National Inpatient Sample Database," says the research team.

The database revealed only 168,325 flu vaccinations among the 7,056,314 total high-risk patients during hospitalization. Researchers found that adults who were 50 years and older were significantly less likely to be vaccinated at 1.8% compared to the general population at 15.3%. The vaccination rate for patients with HIV/AIDS was 2.21%, compared to 8.2% who did not have this disease. The analysis also shows that the vaccination rate for nursing home residents was 1.8%, versus 9.5% for those who live independently. Among obese patients, 2.4% were vaccinated, compared to 9% with a healthy weight. Cardiovascular outcomes were similar to adults over age 50 across the high-risk groups, shows analysis. "The results we found are staggering. It's hard to ignore the positive effect the flu vaccine can have on serious cardiac complications. Some people don't view flu vaccinations as necessary or important, and many may face barriers accessing health care including receiving the flu vaccine," says Mandania.

The study assessed immunization solely in the hospital, so some individuals may have received the flu vaccine in an outpatient setting. "Nevertheless, our study highlights the marked under-underutilization of flu vaccine in high-risk groups and underscores the need for a healthcare policy initiative to increase flu vaccinations among all patients and especially in high-risk groups," says Mandania. 

According to the American Heart Association’s Chief Medical Officer for Prevention, Eduardo Sanchez, the findings provide additional merit for an Association project. "We have partnered with the American Lung Association and the American Diabetes Association to collectively deliver a message to providers and the general public that all adults and all children, by and large, should be getting influenza vaccinations year after year. In particular, for patients who have chronic diseases like high blood pressure, diabetes, or emphysema, it is critically important to get the annual flu vaccine. The potentially serious complications of the flu are far, far greater for those with chronic diseases,” says Sanchez.

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