Comparison of post-acute sequelae following hospitalization for COVID-19 and influenza

Few studies have directly compared the risk and magnitude of post-acute sequelae following COVID-19 and influenza, and most of these studies were conducted before emergence of the Omicron. This study investigated the prevalence of post-COVID conditions and the long-term risk of emergency department (ED) visits, hospitalizations, and deaths in patients with COVID-19 and compared their risk with that of patients with influenza.

A retrospective study based on the TriNetX databases, a global health research network. We identified patients with COVID-19 and influenza who required hospitalization between January 1, 2022, and January 1, 2023. We compared the risk of developing any post-COVID conditions between the two groups and also analyzed each post-COVID-19 condition and all-cause ED visits, hospitalizations, and deaths in both populations during the follow-up 90-180 days.

Before matching, 7,187 patients with COVID-19 were older (63.9 ± 16.7 vs. 55.4 ± 21.2) and were predominantly male (54.0% vs. 45.4%), and overweight/obese (16.1% vs. 11.2%) than 11,266 individuals with influenza. After propensity score matching, 6,614 patients were identified in each group, resulting in well-balanced baseline characteristics. During follow-up, the COVID-19 group had a higher incidence of any post-COVID-19 condition when compared with the influenza group (17.9% vs. 13.0%), with a hazard ratio (HR) of 1.398 (95% CI, 1.251-1.562). Compared to the influenza group, the COVID-19 group had a significantly higher incidence of abnormal breathing (HR, 1.506; 95% CI, 1.246-1.822), abdominal symptoms (HR, 1.313; HR, 1.034-1.664), fatigue (HR, 1.486; 95% CI, 1.158-1.907), and cognitive symptoms (HR, 1.815; 95% CI, 1.235-2.668). Moreover, the COVID-19 group had a significantly higher risk of the composite outcomes during all-cause ED visits, hospitalizations, and deaths when compared with the influenza group (27.5% vs. 21.7; HR, 1.303; 95% CI, 1.194-1.422).

This study indicates that hospitalized COVID-19 patients are at a higher risk of long-term complications when compared with influenza survivors.