Enhancing the Classification of Congenital Heart Defects for Outcome Association Studies in Birth Defects Registries

• Published in: Birth defects research Vol. 116; no. 8; pp. e2393 - n/a
• Main Authors: Stephens, Sara B., Benjamin, Renata H., Lopez, Keila N., Anderson, Brett R., Lin, Angela E., Shumate, Charles J., Nembhard, Wendy N., Morris, Shaine A., Agopian, A. J.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-08-2024; Wiley Subscription Services, Inc
• Subjects: Atria; birth defect registry; Birth defects; Classification; Complexity; Congenital Abnormalities - classification; Congenital Abnormalities - epidemiology; congenital anomalies; Congenital defects; congenital heart defects; Female; Heart; Heart Defects, Congenital - classification; Heart Defects, Congenital - epidemiology; Homogeneity; Humans; Infant; Infant mortality; Infant Mortality - trends; Infant, Newborn; Lesions; Male; Neonates; Outcome Assessment, Health Care - methods; Pediatrics; Registries; surveillance programs; Texas - epidemiology; Texas; birth defect registry; congenital anomalies; surveillance programs; classification; congenital heart defects
• ISSN: 2472-1727; 2472-1727
• DOI: 10.1002/bdr2.2393

ABSTRACT
Introduction
Traditional strategies for grouping congenital heart defects (CHDs) using birth defect registry data do not adequately address differences in expected clinical consequences between different combinations of CHDs. We report a lesion‐specific classification system for birth defect registry–based outcome studies.
Methods
For Core Cardiac Lesion Outcome Classifications (C‐CLOC) groups, common CHDs expected to have reasonable clinical homogeneity were defined. Criteria based on combinations of Centers for Disease and Control‐modified British Pediatric Association (BPA) codes were defined for each C‐CLOC group. To demonstrate proof of concept and retention of reasonable case counts within C‐CLOC groups, Texas Birth Defect Registry data (1999–2017 deliveries) were used to compare case counts and neonatal mortality between traditional vs. C‐CLOC classification approaches.
Results
C‐CLOC defined 59 CHD groups among 62,262 infants with CHDs. Classifying cases into the single, mutually exclusive C‐CLOC group reflecting the highest complexity CHD present reduced case counts among lower complexity lesions (e.g., 86.5% of cases with a common atrium BPA code were reclassified to a higher complexity group for a co‐occurring CHD). As expected, C‐CLOC groups had retained larger sample sizes (i.e., representing presumably better‐powered analytic groups) compared to cases with only one CHD code and no occurring CHDs.
Discussion
This new CHD classification system for investigators using birth defect registry data, C‐CLOC, is expected to balance clinical outcome homogeneity in analytic groups while maintaining sufficiently large case counts within categories, thus improving power for CHD‐specific outcome association comparisons. Future outcome studies utilizing C‐CLOC‐based classifications are planned.