1520 - Respiratory Syncytial Virus Hospitalizations (RSVH) and All-Cause Bronchiolitis Hospitalizations (BH) Among Children Aged ≤ 24 Months at the Start of RSV Season With Bronchopulmonary Dysplasia/Chronic Lung Disease of Prematurity (BPD/CLDP) Before and After the 2014 American Academy of Pediatrics (AAP) Policy

Background: The AAP, in 2014, stopped endorsing palivizumab for use in children with BPD/CLDP born at < 32 weeks’ gestational age (wGA) between the ages of 12 to 24 months not requiring medical support during the 6 months before the start of RSV season and all children with BPD/CLDP born at > 32 wGA. We sought to understand the impact of the guidance change on RSVH and BH in children no longer advised for RSV immunoprophylaxis with palivizumab.

Methods: Children with BPD/CLDP aged ≤ 24 months at the RSV season start and hospitalized for RSV or bronchiolitis during the 2010-2017 RSV seasons (November-March) were studied. RSVH, BH, and BPD/CLDP were defined by International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) and ICD-10-CM codes. ICD-9 codes for wGA combine 31 and 32 wGA into one code. Therefore, for BPD/CLDP, we classified group 1 as children aged 12 to 24 months who were born at < 31 wGA and group 2 as those born at ≥ 31 wGA. The Children’s Hospital Association’s Pediatric Health Information System^® (PHIS) data set was used to describe frequency and characteristics of RSVH and BH and disease severity (including intensive care unit [ICU] admission and mechanical ventilation [MV]) before and after the 2014 AAP policy. Statistical analyses were done using z-tests; SAS version 9.4.

Results: Among children with BPD/CLDP, RSVH rates were 1.7% (1035/59,217) before 2014 and 2.1% (973/45,470) after 2014 (P< 0.0001). RSVH rose after the policy change vs before among children with BPD/CLDP in both group 1 (0.40% vs 0.26%; P< 0.0001) and group 2 (0.22% vs 0.14%; P=0.002). Similarly, BH also increased for both group 1 (P< 0.0001) and group 2 (P=0.002) after the guidance change vs before. Although ICU admissions increased significantly for children with BPD/CLDP in both group 1 (P< 0.0001) and group 2 (P=0.0004), use of MV (P=0.002) increased after 2014 for children with BPD/CLDP in group 1 only. Similar results were observed for BH.

Conclusion: This analysis highlights the increase in RSVH, BH, and associated severity among BPD/CLDP subgroups within the PHIS health system after 2014. Further study of long-term complications associated with RSVH in these children is warranted.