In-Hospital Death and Risk Factors in Adults With Respiratory Syncytial Virus in Spain (2016-2023). A Cross-Sectional Study With Focus on Older Patients.

Background and Aims: Respiratory syncytial virus (RSV) mortality varies across different populations. This study aims to assess RSV mortality in hospitalized adults (≥ 15 years) and identify key risk factors according to age. Methods: This was a retrospective, single-center study conducted in Alicante (Spain), including patients hospitalized for PCR-confirmed RSV infection between 2016 and 2023. Risk factors for death were assessed using multivariable logistic regression. Results: Of 367 patients admitted for RSV, 24 died (6.5%). Mortality was higher in very old adults (≥ 80 years, 8.9%) than in those aged under 80 years (4.8%). Significant risk factors were glomerular filtration rate (GFR) less than 38 mL/min/m2 (adjusted odds ratio [aOR] 3.15, 95% confidence interval [CI] 1.16-8.56), use of high-flow nasal cannula (aOR 3.67, 95% CI 1.15-11.74), and metastatic cancer (aOR 10.01, 95% CI 1.28-78.55). In the group ≤ 79 years (n = 210), risk factors were non-invasive mechanical ventilation (aOR 26.07 95% CI 2.01-338) and C-reactive protein levels over 11 mg/dL (aOR 12.48, 95% CI 1.14-136). In the patients ≥ 80 years (n = 157; 42.8%), low GFR was associated with higher mortality (aOR 4.53, 95% CI 1.36-15.04). Conclusion: RSV deaths increase with age. In-hospital mortality was associated with non-invasive mechanical ventilation and C-reactive protein levels and in patients under 80, and low GFR in older patients.