VITAL-STATISTICS LINKED BIRTH INFANT DEATH AND HOSPITAL DISCHARGE RECORD LINKAGE FOR EPIDEMIOLOGIC STUDIES

A methodology for linking vital statistics linked birth/death data and hospital discharge data is described. The resulting data set combines information on a neonate's sociodemographic characteristics, prenatal care, and mortality aspects and connects it to detailed health outcom e and resource utilization data, thus establishing an extensive databa se for epidemiological studies. In the absence of a universal identifi er common to both databases, our linkage strategy relied on using a vi rtual identifier based on variables common to both data sets. In the c ase of multiple incidences of the same virtual identifier we used seco ndary health status information to optimize the likelihood of linking low birth weight or premature infants in one database to infants of si milar health status in the other while randomizing cases in which no s econdary information was present. Applying our method to the 1992 Cali fornia birth cohort, we could link 563,114 out of 571,189 eligible bir ths (98.59%). Of these links, 91.2% were established on the basis of u nique virtual identifiers. The link was internally consistent and no b ias was evident when comparing variable distributions for all single l ive births in the vital statistics linked birth/death file and linked births in the linked vital statistics linked birth/death and hospital discharge file. Multiple imputation techniques showed that the predict ion error incurred by randomization was negligible. Even though comput ationally intensive, our method for linking the vital statistics linke d birth/death file and the hospital discharge file appeared to be effe ctive. However, it is important to be aware of the limitations of the resulting data set, in particular the fact that it cannot be used for tracking individual cases. The method provides a database suitable for a variety of perinatal epidemiological analyses, such as descriptive studies of disease distribution in neonates, studies of the geographic distribution of disease, and studies of the relationship between risk and outcome. (C) 1997 Academic Press.