Long-term Clinical Outcomes After Hospitalization for Acute Respiratory Illness Due to Respiratory Syncytial Virus

BACKGROUND: Acute respiratory illnesses (ARIs) can be severe in older adults and adults with chronic conditions. We compared long-term outcomes of United States patients aged ≥50 years with ≥1 hospitalized ARI due to respiratory syncytial virus (RSV-ARI cohort) versus controls without ARI (control cohort) and patients with ≥1 hospitalized influenza-ARI (influenza-ARI cohort). METHODS: This retrospective study used 1 October 2015-30 June 2023 claims data to evaluate clinical outcomes across the three cohorts. The index date was defined as the start of an ARI episode. Cumulative incidence functions assessed risks of readmission, all-cause mortality, myocardial infarction (MI), asthma and chronic obstructive pulmonary disease (COPD) exacerbation, and hospitalization due to heart failure (HHF); adjusted risks were compared using multivariable regression models. RESULTS: A total of 14 759, 77 468, and 73 795 patients were selected into the RSV-ARI, influenza-ARI, and control cohorts, respectively. The RSV-ARI cohort had a substantially higher adjusted risk of all-cause mortality than controls, with the highest adjusted hazard ratio (95% confidence interval) 0-30 days post-index (10.772 [9.190, 12.627]). MI risk followed a pattern similar to all-cause mortality. Adjusted risks of asthma exacerbation, COPD exacerbation, and HHF were significantly higher in the RSV-ARI cohort than controls, and similar between RSV-ARI and influenza-ARI cohorts. CONCLUSIONS: RSV-ARI had considerable long-term impact on clinical outcomes, with measurable increases in outcomes associated with RSV-ARI when compared with controls, and similar outcomes compared to influenza-ARI. These findings can inform RSV prevention efforts and support future research on the long-term impact of RSV.