Relation of Concomitant Heart Failure to Outcomes in Patients Hospitalized With Influenza

Influenza is a major public health challenge. Patients hospitalized with influenza who also have heart failure (HF) may be at risk for worse outcomes compared with patients without HF. There is a lack of large studies examining this issue. We queried the 2013 to 2014 National Inpatient Sample for all adult patients (aged ≥ 18 years) admitted with influenza with and without concomitant HF. Using propensity score matching, patients were matched across demographics, discharge weights, and comorbidities. Outcomes included in-hospital mortality, complications, length of stay, and average hospital costs. Of 218,540 influenza hospitalizations, 45,460 (20.8%) had concomitant HF. Patients with HF had higher in-hospital mortality (6.1% vs 3.8%, adjusted odds ratio [aOR] 1.66 [95% confidence interval [CI] 1.44 to 1.91]; p <0.001), acute kidney injury (29.5% vs 22.2%, aOR 1.47 [95% CI 1.37 to 1.57]; p <0.001), acute kidney injury requiring dialysis (2.0% vs 1.0%, aOR 2.08 [1.62 to 2.67], acute respiratory failure (36.2% vs 23.5%, aOR 1.85 [1.73 to 1.97]; p <0.001), and acute respiratory failure requiring mechanical ventilation (17.1% vs 9.3%, OR 2.01 [1.84 to 2.21]; p <0.001), longer length of stay (5.70 ± 0.02 days vs 4.60 ± 0.01 days, p <0.001) and higher average hospital costs ($11,609 ± $52 vs $9,003 ± $38, p <0.001). In conclusion, in patients hospitalized with influenza, HF is associated with increased risk of in-hospital mortality and complications. Our results highlight a need for early recognition and aggressive treatment of HF in these patients to try to improve outcomes.