Abstract 4123849: Respiratory Syncytial Virus (RSV) Cases Involving Hospitalization Are Associated with an Increased Risk of Myocardial Infarction and All−Cause Mortality Among Adults Aged 50 Years and Older

Background: Older adults and adults with comorbidities are at increased risk for severe respiratory syncytial virus (RSV) disease and related complications. Aims: To estimate the risk of myocardial infarction (MI) and all−cause mortality among adults aged ≥50 years hospitalized with RSV compared to those with no recent acute respiratory illness (ARI) and those hospitalized with influenza. Methods: Data from Optum’s de−identified Clinformatics® Data Mart Database were analyzed (October 2015–June 2023) in this retrospective cohort study. Adults aged ≥50 years with ≥12 months of continuous enrollment were assigned to cohorts based on RSV or influenza hospitalization (from ICD−10 codes; RSV and flu cohorts) or no recent ARI (control cohort). Index dates for RSV and flu cohorts were the start of an ARI that included hospitalization. Baseline characteristics were measured in the 12 months pre−index. MI (from ICD−10 codes) and all−cause mortality were measured during follow−up and compared between cohorts using time−varying coefficient multivariable adjusted Cox models (MI results accounted for the competing risk of death). Results: In the RSV cohort (n=14,759), mean age (76.5 years) and mean Charlson comorbidity index (CCI; 3.3) were higher than the flu (n=77,468; 75.4 years, CCI=2.9) and control (n=73,795; 69.5 years, CCI=1.0) cohorts. Adjusted HRs (95% CI) for MI and all−cause mortality risk were significantly higher in the RSV vs control cohort across follow−up, ranging from 30.96 (26.22–36.54) within 30 days post−index to 2.26 (2.04–2.51) >365 days post−index for MI and 10.77 (9.19–12.63) within 30 days post−index to 2.29 (2.18–2.42) >365 days post−index for mortality. Compared to the flu cohort, adjusted MI and mortality risk in the RSV cohort were lower during the 30 days post−index (MI: 0.87 [0.82–0.92]; mortality: 0.84 [0.78–0.90]) but higher >365 days post−index (MI: 1.11 [1.01–1.22]; mortality: 1.05 [1.01–1.10]). Conclusion: MI and all−cause mortality risk were higher for hospitalized RSV cases compared to controls. Smaller differences in outcomes were observed when comparing hospitalized RSV cases with hospitalized influenza cases, with varying direction over time. With existing evidence of increased MI and mortality risk after influenza and these findings on MI and mortality risk after RSV, future research should aim to further understand the impact of RSV on cardiovascular outcomes and assess the role of RSV prevention in lowering the risk of MI and mortality.