Assessing Clinical Improvement of Infants Hospitalized for Respiratory Syncytial Virus-Related Critical Illness.

BACKGROUND

Pediatric respiratory syncytial virus (RSV)-related acute lower respiratory tract infection (LRTI) commonly requires hospitalization. The Clinical Progression Scale Pediatrics (CPS-Ped) measures level of respiratory support and degree of hypoxia across a range of disease severity, but it has not been applied in infants hospitalized with severe RSV-LRTI.

METHODS

We analyzed data from a prospective surveillance registry of infants hospitalized for RSV-related complications across 39 U.S. PICUs from October through December 2022. We assigned CPS-Ped (0=discharged home at respiratory baseline to 8=death) at admission, days 2-7,10, and 14. We identified predictors of clinical improvement (CPS-Ped≤2 or 3-point decrease) by day 7 using multivariable log-binomial regression models and estimated the sample size (80% power) to detect 15% between-group clinical improvement with CPS-Ped versus hospital length of stay (LOS).

RESULTS

Of 585 hospitalized infants, 138 (23.6%) received invasive mechanical ventilation (IMV). Of the 49 (8.4%) infants whose CPS-Ped score worsened by 2 points after admission, one died. Failure to clinically improve by day 7 occurred in 205 (35%) infants and was associated with age <3 months, prematurity, underlying respiratory condition, and IMV in the first 24 hours in the multivariable analysis. The estimated sample size per arm required for detecting a 15% clinical improvement in a potential study was 584 using CPS-Ped clinical improvement versus 2,031 for hospital LOS.

CONCLUSIONS

CPS-Ped can be used to capture a range of disease severity and track clinical improvement in infants who develop RSV-related critical illness and could be useful for evaluating therapeutic interventions for RSV.