(250) Comparison of Diagnoses Code Profile and Major Congenital Malformation (MCM) Prevalence across US and EU MCM Classification Systems

Background: Major congenital malformation (MCM) prevalence estimates based on a European network of population-based registries for the epidemiological surveillance of congenital malformations (EUROCAT), Metropolitan Atlanta Congenital Defects Program (MACDP), National Birth Defects Prevention Network (NBDPN), and New York State Department of Health-Birth Defects Registry (NYSDOH-BDR) classification systems are used as benchmarks in multi-country pregnancy safety studies. Alignment of the MCM diagnosis code profiles across these classification systems and assessment of potential differences in prevalence estimates is warranted.

Objectives: To align diagnosis codes profiles and MCM prevalence estimates from four commonly used MCM classification systems in the United States and European Union.

Methods: A comparison of individual MCMs within each body system category was conducted. Next, MCM ICD-9/10 diagnostic codes under each body system category were aligned across the four classification systems. Prevalence estimates for each MCM outcome will be obtained by body system category in the Dorsata data. Dorsata is an Obstetric-Gynecology-focused electronic health record (EHR) interface with point-of-care study enrollment/referral capabilities as well as retrospective EHR with external linkage options. Dorsata’s maternal and birth data includes all peripartum clinical care and prescription data and demographic and social determinants of health data, which may be linked to external maternal and pediatric data. To quantify these findings, MCM prevalence by body system for each classification system will be reported using Dorsata data.

Results: EUROCAT categorized MCMs into 13 categories, NBDPN 10 categories, NYSDOH-BDR 11 categories, while MACDP organized by 21 ICD-9 code headings. Each body system category included similar MCMs across EUROCAT, NBDPN and NYSDOH-BDR, though there were a few instances when mapping MCM categories were not aligned (e.g., NYSDOH-BDR had one category for MCMs of the eye, ear, face, and neck, whereas EUROCAT and NBDPN had eye malformations and malformations of ear, face, and neck as two separate categories). ICD-10 codes for EUROCAT and NYSDOR-BDR level 1 codes (e.g., 3-character ICD codes) mapped closely to one another, though, there were slight differences in ICD-10 exclusions applied to each MCM. EUROCAT and NBDPN ICD-10 codes mapped at level 1 for many of the MCMs under nervous system malformations, congenital heart defects, and oro-facial clefts categories. Level 1 ICD-9 codes for EUROCAT and MACDP also aligned closely.

Conclusions: For multi-country post-marketing requirement and post-authorization safety studies, NYSDOR-BDR and EUROCAT are recommended for alignment in MCM classification.