Flu Shots Are More Important Than Ever for People with Diabetes, ASCVD

October 14, 2020

Flu increases the risk of heart attack, especially among people with diabetes and atherosclerotic cardiovascular disease (ASCVD). COVID-19 and the possibility of co-infection makes getting vaccinated against the flu particularly important this year.

Eat healthier foods, get more exercise, lose weight, take a statin if your LDL cholesterol level is elevated, and take an antihypertensive medication if you have high blood pressure blood — these are some of things that many Americans think about doing to lower their risk of having a heart attack.

The annual flu shot doesn’t make that list but it should. There’s little doubt that getting sick with the flu markedly increases the risk of having a heart attack. Researchers have been collecting evidence on the association between flu and cardiovascular mortality since the 1930s. And the heart attack risk from flu is especially high among people with diabetes and those with atherosclerotic cardiovascular disease (ASCVD).

In an “expert analysis” piece for that was posted yesterday on the American College of Cardiology’s website, Gowtham Grandhi, M.D., M.P.H., Priyanka Bhugra, M.D., and Khurram Nasir, MBBS, FACC, make a convincing case for flu shots being especially important this year for people with diabetes or ASCVD because of the COVID-19 pandemic and the possibility of infection by both viruses. They point to research showing that, in the past, about 1 in 3 individuals with diabetes do not get annual flu shot. They cite other studies showing that the ratio is roughly the same for people with ASCVD.

“Given the suboptimal rates of annual influenza vaccination among DM (diabetes mellitus) and increased risk of coinfection with COVID-19 this influenza, vaccination against influenza among these high-risk individuals is critical until an effective vaccine against COVID-19 is made available and accessible to everyone,” say the trio. It is imperative, they say, to provide flu shots at alternative and nontraditional sites such as grocery stores and parks “to enhance equitable vaccination coverage while maintaining appropriate social distancing and infection control measures.”

Grandhi, Bhugra and Nasir cite a study published in Diabetes Care last month that used data from the Danish disease registry to show that flu shots reduced all-cause mortality, cardiovascular disease mortality, and heart attack and stroke mortality by about 15% among people with diabetes. That translates into number needed to treat of 1,333 to prevent one death. They also reference a 2015 meta-analysis of case-control studies that showed that flu vaccination was associated with a 29% decreased risk of heart attack.

Researchers have come up with various explanations for flu increasing heart attack risk. According to Grandhi, Bhugra and Nasir’s brief account, infection with a flu virus stirs up inflammation that has the effect of destabilizing atherosclerotic plaque so it is more likely to rupture, resulting in an occluded coronary artery.