Flu shots reduce all-cause, CV death for adults with diabetes
Influenza vaccination was significantly associated with reduced risks for all-cause death, cardiovascular death, and death from acute myocardial infarction or stroke among adults with diabetes, according to an analysis of registry data.
“Because patients with diabetes have a high risk of acute MI and stroke in addition to an increased susceptibility for influenza infection, they may be at high risk of suffering acute ischemic events secondary to influenza infection,” Daniel Modin, MB, a researcher associate with the department of cardiology at Herlev and Gentofte Hospital and the University of Copenhagen, Denmark, and colleagues wrote in the study background. “This prompts the questions of whether influenza vaccination may prevent cardiovascular mortality in patients with diabetes. If this is the case, the safety profile, cost efficiency and feasibility of vaccination make it ideal for improving outcomes in diabetes.”
Modin and colleagues analyzed nationwide register data to identify 241,551 adults with diabetes in Denmark during nine consecutive influenza seasons from 2007 to 2016 (median follow-up, four seasons). Diabetes was defined as use of glucose-lowering medication. Patient exposure to influenza vaccination was assessed before each influenza season. Researchers considered the outcomes of death from all causes, death from CV causes, and death from acute MI or stroke. For each season, patients were monitored from Dec. 1 until April 1 the next year.
The vaccine coverage during study seasons ranged from 24% to 36%.
During follow-up, 8,207 patients died of all causes (3.4%), 4,127 patients died of CV causes (1.7%) and 1,439 patients died of acute MI or stroke (0.6%). After adjustment for confounders, vaccination was associated with reduced risks for all-cause death (HR = 0.83; P < .001), CV death (HR = 0.84; P < .001), death from acute MI or stroke (HR = 0.85; P = .028) and a reduced risk for hospitalization for acute complications associated with diabetes, such as diabetic ketoacidosis, hypoglycemia, or coma (HR = 0.89; P = .006).
In subgroup analyses stratified by insulin therapy use at baseline, vaccination was significantly associated with a reduced risk for all-cause death among adults not prescribed insulin therapy (HR = 0.85; 95% CI, 0.79–0.91) and CV death (HR = 0.83; 95% CI, 0.75-0.92). Among those prescribed insulin therapy at baseline, vaccination was also significantly associated with a reduced risk for all-cause death (HR = 0.8; 95% CI, 0.72-0.88) and CV death (HR = 0.86; 95% CI, 0.74-0.99).
“In this nationwide register-based study including > 240,000 patients with diabetes, we have shown that influenza vaccination is significantly associated with reduced risks of all-cause, cardiovascular and stroke/acute MI death despite rigorous control for confounding factors,” the researchers wrote. “We have also shown that vaccination is significantly associated with a reduced incidence of acute diabetes complications. To our knowledge, this is the largest study to date examining the association between influenza vaccination and outcome in patients with diabetes.”
As Healio previously reported, data from the 2019 European Society of Cardiology Congress showed that influenza vaccination is associated with a significantly reduced risk for all-cause mortality, CV mortality and death from acute MI and stroke in patients with hypertension. In that study, vaccination was attributed to an 18% relative reduction in all-cause deaths (adjusted HR = 0.82; 95% CI, 0.79-0.85), a 16% reduction in CV deaths (aHR = 0.84; 95% CI, 0.8-0.89) and a 10% relative reduction in death from stroke or acute MI (aHR = 0.9; 95% CI, 0.82-0.98) in patients with hypertension.