Flu vaccination in patients with diabetes reduces hospitalization risk
Influenza vaccination of patients with diabetes decreased the risk for influenza-related hospitalization by 46%, according to a study examining six influenza seasons in Spain.
“People with diabetes are at high risk for severe influenza complications. Influenza vaccination is recommended to these patients, but its effect remained inconclusive,” Jesús Castilla, MD, PhD, MPH, of the Instituto de Salud Pública de Navarra and the CIBER Epidemiología y Salud Pública in Spain, told Healio. “We estimated the effect of the influenza vaccination status in the current and prior seasons in preventing laboratory-confirmed influenza hospitalization in patients with diabetes.”
Castilla and colleagues assessed data from patients with influenza-like illnesses who attended hospitals and primary health care centers and were tested for influenza during the six influenza seasons between 2013-2014 and 2018-2019 in Navarre, Spain. The researchers compared the vaccination status in two groups: (1) confirmed influenza cases vs. negative controls in a cohort of inpatients who all had diabetes and (2) inpatients vs. outpatients who all also had influenza and diabetes. The researchers also compared the effect of influenza vaccination between patients with diabetes and patients with other chronic conditions, as well as patients aged 60 years and older.
According to Castilla, the results demonstrated that the vaccination effect against influenza hospitalizations in patients with diabetes was not inferior to that in older patients or patients with chronic conditions.
Data from the study showed that 569 (34%) of 1,670 inpatients with diabetes who were tested were confirmed to have influenza; 1,101 were test-negative controls. The average effect in preventing influenza hospitalization was 46% (95% CI, 28%-59%) for current-season vaccination and 44% (95% CI, 20%-61%) for vaccination in previous seasons compared with unvaccinated patients in current and prior seasons. Furthermore, Castilla and colleagues found that current-season influenza vaccination decreased the likelihood of hospitalization among patients with diabetes and laboratory-confirmed influenza, which researchers say can be explained as a vaccine-related reduction in severity among patients for whom the influenza infection was not prevented.
“Influenza vaccines received in recent seasons may retain some protective effect in people who were not vaccinated in the current season,” Castilla said. “When influenza vaccination fails to prevent influenza in patients with diabetes, it can still reduce the probability of hospitalization.”
He added that the study results “reinforce the recommendations for annual influenza vaccination in patients with diabetes.”