Study Explores Mortality Rates and Risk Factors in Patients Hospitalized for RSV

A study published in Clinical Microbiology and Infection found that approximately 25% of patients hospitalized for respiratory syncytial virus (RSV) required intensive care unit (ICU) admission, and the mortality rate among hospitalized patients overall was 6.6%.

RSV causes lower respiratory tract infections in young children and is responsible for seasonal respiratory infections in older adults, with an estimated 3% to 10% infection rate in adults per year. However, epidemiological data on severe RSV infections for adults who are hospitalized in ICUs is limited.

This study aimed to determine the risk factors of mortality, determine risk factors of ICU admission and invasive mechanical ventilation requirement, and describe the characteristics of those who receive ribavirin for RSV.

Patients aged 18 years and older who were hospitalized in Assistance Publique-Hopitaux de Paris hospitals from January 1, 2015, to December 31, 2019 were included in the study. International Classification of Diseases, 10th Edition (ICD-10) codes were used to define the diagnosis of an RSV infection.

Age, sex, comorbidities, duration of hospital stay, ICU admission, variables in patient management, need for supplemental oxygen, and use of corticosteroids, antibiotics, ribavirin, and occurrence of co-infection were all collected from patients at hospital admission and during their stay in the hospital.

In-hospital mortality was the primary end point, with ICU admission, need for invasive mechanical ventilation, occurrence of co-infection, and effect of ribavirin use on mortality as secondary end points.

A total of 1168 patients at 25 hospitals were included in the retrospactive study. Of these patients, 75.3% were admitted to conventional inpatient units and 24.7% required ICU admission. Annual peaks in hospitalization occurred in November and January.

Overall, patients were mostly female (54%), had a median (IQR) age of 75 (63-86) years, and many patients had underlying comorbidities, including hypertension (46.4%), chronic heart failure (34.4%), immunosuppression (29.5%), and chronic obstructive pulmonary disease (COPD) (28.6%). The majority of patients admitted received antibiotics (82.1%) whereas 43.4% received corticosteroids.

Patients who were admitted to the ICU were more often male, younger, presented cardiovascular or respiratory comorbidities more often, and had more co-infections compared with those who did not need admission to the ICU. Obesity (adjusted odds ratio [aOR], 1.78; 95% CI, 1.26-2.53), hypertension (aOR, 1.45; 95% CI, 1.05-1.99), chronic heart failure (aOR, 2.18; 95% CI, 1.56-3.03), COPD (aOR, 2.79; 95% CI, 1.90-4.09), chronic respiratory failure (aOR, 1.64; 95% CI, 1.10-2.44), and co-infection (aOR, 3.75; 95% CI, 2.43-5.78) were all found to be associated with an increased risk of admission to the ICU. Patients aged 65 years and older and female patients had a lower risk of admission to the ICU.

The mortality rate in the overall cohort was 6.6% (95% CI, 5.2-8.2), compared with 12.8% (95% CI, 9.2-17.3) for those admitted to the ICU. Patients aged 85 years and older and those who had neutropenia, acute respiratory failure, and a need for non-invasive or invasive mechanical ventilation support were at higher risks of mortality.

Patients who received ribavirin were younger (62 [55-69] vs 75 [63-86] years), male (70.8% vs 44.9%), and immunocompromised (95.8% vs 26.7%) compared with patients who did not receive ribavirin. Patients who received ribavirin also needed invasive mechanical ventilation support (18.8% vs 6.9%) and vasopressors (14.6% vs 5.3%) more often compared with those who did not need ribavirin.

Biases in data collection could have occurred due to the study's observational nature, and selection bias could have occurred due to the use of ICD-10 codes. Microbiology data for hospitalized patients was not collected directly and instead had to be sought out through medical reports and ICD-10 coding, which could have led to the underestimation of diagnoses.

The researchers concluded that the hospital mortality rate for patients admitted to the hospital for RSV was 6.6%, with the highest risk factors for mortality being older age, neutropenia, acute respiratory failure, and invasive ventilation during ICU hospitalization.

Reference

Celante H, Oubaya N, Fourati S, et al. Prognosis of hospitalized adult patients with respiratory syncytial virus infection: a multicenter retrospective cohort study. Clin Microbiol Infect. Published online March 11, 2023. doi:10.1016/j.cmi.2023.03.003