RSV Linked With Hospital Mortality Rates Typically Seen With the Flu

Respiratory syncytial virus (RSV) infection is associated with high in-hospital mortality at levels comparable with influenza infection when adults are admitted to the ICU, according to a recent study.

“Influenza is another respiratory virus routinely tested for in patients in the ICU with respiratory symptoms because of its well-known morbidity and mortality, but no studies specifically have compared RSV and influenza infections in adult patients in the ICU,” wrote the authors about their motivation for the study, which was published in Chest Journal.

The retrospective study, conducted across 17 sites in France and Belgium, aimed to determine the characteristics and outcomes of adult patients in the ICU with RSV infection.

Characteristics and outcomes of adult patients with RSV infection were compared with those with influenza infection between November 2011 and April 2018.

Patients with RSV were matched by institution and day of diagnosis with patients with influenza infections. The cohort included 618 patients, 309 with RSV infection and 309 with influenza infection.

In comparing mortality rates, researchers adjusted for prognostic factors including sex, age, main underlying conditions, and concurrent bloodstream infection.

Patients with RSV infection were found to be significantly more likely to have an underlying chronic respiratory condition (60.2% vs 40.1%).

Additionally, patients with RSV were significantly more likely to be immunocompromised (35% vs 26.2%).

Only 6.3% of patients were considered young and previously healthy. The proportion of patients with RSV who were young and previously healthy was 2.9%, significantly lower than for patients with influenza (9.7%), indicating that severe RSV infection mainly occurs in patients with comorbidities.

Characteristics at diagnosis varied between groups in patients with critical illness. RSV infection was associated with clinical signs of airway obstruction, with 49.5% of patients showing signs of airway obstruction.Of the patients with RSV infection, 50% had a diagnosis of chronic obstructive pulmonary disease, asthma, or both.

ICU and hospital lengths of stay were comparable between patients with RSV and patients with influenza.

Mortality was not significantly different between hospitalized patients with RSV infection and influenza infection; the RSV group was 23.9% compared with 25.6% in the influenza group.

The authors suggested a need to identify interventions to prevent and treat severe RSV infection, based on these findings.

The study had several limitations. A causal relationship between the viral infections and patient outcomes could not be demonstrated.

However, 95% of patients demonstrated respiratory symptoms and relatively few showed another detected cause for the respiratory condition, supporting causality between the viral infections detected and the relatively poor outcomes, according to the authors.

While the management of patients was not homogenous among centers due to local protocols, the authors assert that patient matching by data and hospital reduced risk of bias for between-group comparisons.

Reference

Julien C, Benjamin Z, Eve G, et al. characteristics and outcomes of patients in the ICU with respiratory syncytial virus compared with those with influenza infection. CHEST Journal. 2022;161(6):1475-1484. doi:10.1016/j.chest.2021.12.670