FLORENCE, ITALY – Influenza vaccination of heart failure patients cut their rate of hospitalization for cardiovascular disease by nearly a third during the year following vaccination in a study of more than 59,000 British heart failure patients.
Influenza vaccination of heart failure patients also cut their rate of hospitalization for respiratory infections by a statistically significant 16% during the year following vaccination, Dr. Kazem Rahimi said at a meeting held by the Heart Failure Association of the ESC.
“In the absence of randomized trials, this [observational] study of 59,202 heart failure patients provides the most compelling evidence to date for the protective effect of influenza vaccination on hospital admissions,” said Dr. Rahimi, a cardiologist and epidemiologist who is deputy director of the George Institute for Global Health at the University of Oxford (England).
The analysis also showed that influenza vaccination of heart failure patients had no significant effect on all-cause hospitalizations.
Dr. Rahimi and his associates analyzed electronic health records from primary and secondary care settings in England during 1990-2013, from which they identified 59,202 heart failure patients with records for at least 1 year of influenza vaccination and at least 1 year without vaccination. The patients averaged 75 years old and were divided equally among women and men.
To control for potential confounding factors, they used a self-control model in which hospitalizations for each heart failure patient during the year following an influenza vaccination were compared with an adjacent year for that same patient when no vaccination occurred.
The results showed that the incidence of hospitalizations for cardiovascular diseases fell by a statistically significant 30% in the year following an influenza vaccination, compared with one or more adjacent years without vaccination. The protection again hospitalization was strongest during the second month following vaccination and then gradually waned over the ensuing year; by about 10 months following vaccination the protection effect had disappeared.
The study also looked at influenza vaccine uptake by heart failure patients through the 24-year period examined. During that time, the vaccination uptake rate rose from a low of less than 10% in 1990 to a peak rate of just over 60% in 2006, after which the rate gradually declined to a rate of just under 50% in 2013. Dr. Rahimi attributed the rise in uptake during the period from 1990 to 2006 in part to incentives that primary care physicians in England began receiving to administer influenza vaccine to their patients. “Higher uptake of annual vaccination in heart failure patients may help alleviate the burden of influenza-related hospital admissions,” he said.
Dr. Rahimi had no disclosures.
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