PIN20 - Respiratory Illness (RI) and Respiratory Syncytial Virus (RSV)-Related Hospitalization (RSVH) in Infants with Congenital Diaphragmatic Hernia (CDH) in the Caress Registry (2005-2017)

Abstract

To compare the hazard ratio for RI hospitalization (RIH) and RSVH in CDH infants versus: 1) non- risk infants (NR; those without morbidities, who received RSV prophylaxis as part of multiple births) and 2) infants prophylaxed for standard indications (SI; prematurity ≤35 weeks gestational age, chronic lung disease or significant congenital heart disease) in the Canadian RSV Evaluation Study of Palivizumab (CARESS). CARESS is a prospective study of children who received ≥1 injection of palivizumab across 32 Canadian sites. Neonatal and demographic data were collected at enrolment. Utilization, adherence, and respiratory illness event data were collected monthly. Demographic comparisons were performed using t-tests and chi-square tests. Cox proportional hazards analyses were conducted to compare RIH and RSVH risks across groups adjusted for potential confounders. 25,003 infants were enrolled; 163 CDH, 339 NR, and 20,551 SI. Palivizumab adherence, defined as receiving all expected injections during the RSV season within appropriate dose intervals, was 75% overall and similar across groups. 1724 infants were hospitalized on 2054 occasions (crude RIH rates: CDH 8.6%; NR: 2.4%; SI: 6.2%). CDH infants had a significantly increased RIH risk versus NR (HR=2.6, 95%CI 1.0-6.7, p=0.05) but not SI infants (HR= 1.0, 95%CI 0.6-1.8, p=0.92). Crude RSVH rates were: 0.6% (CDH), 0.3% (NR), and 1.3% (SI), with no significant difference in RSVH risk between CDH infants and the other two groups (NR: HR= 2.5, 95%CI 0.2-40.4, p=0.52; SI: HR= 0.6, 95%CI 0.1-4.3, p=0.61). Due to lung abnormalities and complex ventilation modalities in the neonatal period, CDH infants had an approximately 3-fold increased risk of RIH compared to NR but not SI infants. RSVH risk was similar across all groups. These findings imply that CDH infants may benefit from palivizumab, similar to other high risk groups.