The utility of the National Death Index as a supplemental data source in ascertaining 5-year mortality among Texas heterotaxy cases.

INTRODUCTION: The Texas Birth Defects Registry (TBDR) is an active surveillance system which covers all pregnancy outcomes and routinely links birth defects cases to in-state vital records. This study describes the value of using the National Death Index (NDI) data to supplement Texas state death certificates from vital records for a birth defects survival analysis. METHODS: The cohort for this study were live-born cases with heterotaxy, a complex birth defect, delivered to Texas residents between 1999 and 2006, with a 5-year follow-up period for survival determination. Cases were linked to their Texas birth and death certificates, if present. Any live-born case that did not link to a Texas death certificate was sent to the NDI to search for any deaths that occurred. RESULTS: We identified 366 heterotaxy cases that were live-born in delivery years 1999-2006, 134 of which were linked to a Texas death certificate. The 232 remaining cases were sent to the NDI to search for a death certificate not found previously. This resulted in only 2 additional out-of-state deaths. DISCUSSION: Future quantification of NDI yields for birth defects survival studies would assist with further assessing the efficacy of utilizing the NDI for capturing early childhood mortality in states that routinely link to in-state death certificates.