People with type 2 diabetes who receive the influenza vaccine may be less likely to be admitted to hospital for myocardial infarction, stroke and heart failure, according to new research published in CMAJ (Canadian Medical Association Journal).
"In this large population-based study, influenza vaccination in people with type 2 diabetes was associated with reductions in rates of hospital admission for acute cardiovascular and respiratory diseases, and in all-cause mortality across 7 influenza seasons," writes Dr. Eszter Vamos, Department of Primary Care & Public Health, Imperial College Healthcare NHS Trust, London, United Kingdom, with coauthors.
People with type 2 diabetes are at high risk of cardiovascular disease. Many countries encourage vaccination against influenza, especially in older people and people with multiple health issues such as diabetes, although there is uncertainty about vaccine effectiveness in these groups.
A large study involving 124 503 patients with type 2 diabetes looked at whether the influenza vaccine helped protect against hospital admission for people with cardiovascular events over a 7-year period. In addition to adjusting for demographic, social and clinical characteristics, investigators also studied the summer months, when the occurrence of influenza is low, to better understand the differences between people with type 2 diabetes who received and did not receive influenza vaccine.
Researchers used the summer period to make further adjustments and better account for the differences between vaccinated and unvaccinated people. After these adjustments, the researchers found that vaccination was associated with a 19% reduction in hospital admissions during flu season for heart attack (acute myocardial infarction), 30% for stroke, 22% for heart failure and 15% for pneumonia or influenza compared with unvaccinated people with diabetes. As well, people who were vaccinated had a 24% lower death rate than patients who were not vaccinated.
There are few studies that have assessed the effectiveness of the influenza vaccine in people with diabetes.
"This study has shown that people with type 2 diabetes may derive substantial benefits from current vaccines, including protection against hospital admission for some major cardiovascular outcomes. These findings underline the importance of influenza vaccination as part of comprehensive secondary prevention in this high-risk population," the authors conclude.