Heart Failure Plus Flu: A Deadly Combination

An analysis of data for more than 100 000 US hospitalizations for heart failure (HF) found that having influenza was an independent predictor of complications, longer length of stay, and death while in hospital.

Specifically, having HF and the flu was linked to 15% increased likelihood of death while in the hospital, 95% increased likelihood of acute respiratory failure, 75% increased likelihood of requiring mechanical ventilation, 8% increased likelihood of acute kidney injury, and 37% increased likelihood of dialysis.

The findings were published on February 2, 2019 in JACC: Heart Failure.¹

“This has important implications for both patients and providers who take care of patients with HF and highlights the need for heightened efforts to prevent influenza infection in this high-risk cohort,” wrote first author Muhammad Panhwar, MD, of Case Western Reserve University School of Medicine, (Cleveland, Ohio), and colleagues.

Rates of flu vaccination are low in the general population, and not much better in patients with HF. One study reported that only about half of people with HF in North America are vaccinated for the flu.²

“Influenza vaccination has been shown to reduce morbidity and mortality in patients with HF,” the authors stressed.

About 6 million people in the US currently have HF, and are at increased risk for complications related to the flu, including heart attack, decompensated HF and pneumonia. Yet knowledge about the extent of the problem has been limited until now.

In the study, researchers analyzed data for 2013 to 2014 from the National Inpatient Sample, a national database that covers over 94% of hospitalizations in the US. The analysis matched patients hospitalized with HF and the flu to those hospitalized with HF but without the flu.

Patients hospitalized with HF and the flu had significantly longer length of stay than those with HF but without the flu. However, average hospital costs were about the same for the two groups.

After controlling for month of hospitalization, flu emerged as an independent predictor of hospital death, adverse outcomes and increased length of stay.

The study included only hospitalized patients, who may be sicker and have higher risk for flu-related complications. Results may not generalize to outpatients.

REFERENCES1. Panhwar MS, Kalra A, Gupta T, et al. Effect of influenza on outcomes in patients with heart failure. JACC Heart Fail. 2019;7:112-117. doi: 10.1016/j.jchf.2018.10.011

2. Vardeny O, Claggett B, Udell JA, et al. Influenza vaccination in patients with chronic heart failure: The PARADIGM-HF Trial. JACC Heart Fail. 2016;4:152-158. doi: 10.1016/j.jchf.2015.10.012.