737. The Prevalence of Diagnosed Chronic Lung Disease in US Infants by Gestational Age: Implications for RSV Policy

BACKGROUND: Perinatal chronic lung disease (CLD), previously referred to as bronchopulmonary dysplasia (BPD), is associated with preterm birth and occurs rarely among term infants. Children with CLD are at elevated risk for severe RSV disease in the first 2 years of life. Definitions of CLD/BPD identify infants who require supplemental oxygen at 28 days of life or 36 weeks postmenstrual age, with no restriction by gestational age (GA) at birth. However, the AAP Committee on Infectious Disease guidance does not recommend RSV immunoprophylaxis for infants with CLD born at ≥32 weeks gestational age (wGA), even though infants with CLD/BPD up to 41 wGA were included in pivotal efficacy studies. This study determined the prevalence of diagnosed CLD in US infants as a function of wGA at birth and the number of infants with CLD born at ≥32 wGA. METHODS: The Kids’ Inpatient Database (KID) is a nationally representative survey conducted every 3 years in the United States. Birth hospitalization data from KID were utilized to estimate the prevalence of CLD (ICD-9 = 770.7) among US infants in 2003–2012 overall and as a function of coincident codes for GA (ICD-9 = 765.21–765.29, reported in 2-week intervals). The prevalence of CLD among 32 wGA infants was imputed based on the distribution of CLD cases as a function of wGA. KID data from 2015 were not available due to the transition to ICD-10 coding. RESULTS: A total of 31,984 infants had a CLD diagnosis across the 4 years, representing 0.2% of US births. The prevalence of CLD declined from 20.8 to 19.5 per 10,000 between 2003 and 2012. Of those, 25,554 infants with CLD (80%) had GA coded in the database. The percentage of CLD infants born at <27 wGA increased from 44% in 2003 to 52% in 2012, whereas the percentage at ≥29 wGA decreased from 27% to 21% (figure). Overall, the percentages born at 31–32, 33–34, and >34 wGA were 5.7%, 2.2%, and 1.2%, respectively. An estimated 5.7% of infants with CLD were born at ≥32 wGA, representing 0.9 of every 10,000 US births or ~350 infants annually. CONCLUSION: Fewer than 400 infants are born at ≥32 wGA and diagnosed with CLD annually in the United States. The rationale for excluding this small but high-risk group of infants from the population recommended for RSV immunoprophylaxis is not clear. Funded by AstraZeneca [Image: see text] :Disclosures. C. S. Ambrose, AstraZeneca: Employee, Salary and Stocks. X. Jiang, EpiStat Institute: Employee, Consulting fee and Salary. AstraZeneca: Consultant, Consulting fee. K. Mavunda, AstraZeneca: Speaker’s Bureau, Speaker honorarium.