Effects of atrial fibrillation on outcomes of influenza hospitalization

There is little information available on AF and its association with outcomes in adult influenza hospitalizations.

The National Inpatient Sample was queried from years 2009-2018 to create a cohort of discharges containing an influenza diagnosis. AF was the primary exposure. Univariate and multivariate regression analysis was used to describe the association of AF with clinical and healthcare-resource outcomes. Finally, a doubly-robust analysis using average treatment effect on the treated (ATT) propensity score weighting was performed to verify the results of traditional regression analysis.

After adjustment, the presence of AF during influenza hospitalization was associated with higher odds of in-hospital mortality (aOR 1.56, 95 % CI 1.49 - 1.65), acute respiratory failure (aOR 1.22, 95 % CI 1.19 - 1.25), acute respiratory failure with mechanical ventilation (aOR 1.37, 95 % CI 1.32 - 1.41), acute kidney injury (aOR 1.09, 95 % CI 1.06 - 1.12), acute kidney injury requiring dialysis (aOR 1.61, 95 % CI 1.46 - 1.78) and cardiogenic shock (aOR 1.90, 95 % CI 1.65 - 2.20, all p-values < 0.0001). These findings were validated in our propensity score analysis using ATT weights. The presence of AF was also associated with higher total charges and costs of hospitalization, as well as a significantly longer length of stay (all p-values < 0.0001).

AF is a cardiovascular comorbidity associated with worse clinical and healthcare resource outcomes in influenza requiring hospitalization. Its presence should be used to identify patients with influenza at risk of worse prognosis.