Accuracy of ICD-9-CM coding to identify small for gestational age newborns.

TitleAccuracy of ICD-9-CM coding to identify small for gestational age newborns.
Publication TypeJournal Article
Year of Publication2015
AuthorsPhiri K, Hernandez-Diaz S, Tsen LC, Puopolo KM, Seeger JD, Bateman BT
JournalPharmacoepidemiol Drug Saf
Volume24
Issue4
Pagination381-8
Date Published2015 Apr
ISSN1099-1557
KeywordsAdolescent, Adult, Birth Weight, Databases, Factual, Diagnostic Techniques, Obstetrical and Gynecological, Female, History, 21st Century, Humans, Infant, Small for Gestational Age, International Classification of Diseases, Middle Aged
Abstract

PURPOSE: This study aimed to evaluate the accuracy of the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis code for small for gestational age (SGA) recorded in administrative healthcare records using birthweight and gestational age information recorded in electronic medical records.

METHODS: We used billing and medical records from women aged 13-55 years who delivered at a tertiary care center in the USA between 2004 and 2011. Information on birthweight, gestational age at birth, and ICD-9-CM code for SGA, 656.5x, was abstracted from the database. Each infant's birthweight percentile for gestational age was calculated on the basis of published US references; infants below the 10th percentile were classified as SGA. The performance characteristics of SGA ICD-9-CM diagnosis code against SGA classification based on birthweight and gestational age were calculated, for all deliveries and by strata of demographic and delivery characteristics.

RESULTS: We identified 51 292 singleton live birth deliveries. The prevalence of SGA infants calculated from birthweight and gestational age at birth was higher (13%) than the prevalence based on ICD-9-CM code (2%). Sensitivity of the SGA ICD-9-CM code was 14.2%, specificity was 99.7%, positive predictive value was 86.8%, and negative predictive value was 88.4%. Stratification by demographic and delivery characteristics yielded similar results.

CONCLUSIONS: Identification of SGA infants using ICD-9-CM code, 656.5x, from administrative healthcare records has low sensitivity but high specificity; the accuracy did not differ across demographic and delivery characteristics. Thus, although this source of information would underestimate the prevalence of SGA, it could produce valid relative risk estimates.

DOI10.1002/pds.3740
Alternate JournalPharmacoepidemiol Drug Saf
PubMed ID25656656
PubMed Central IDPMC4533984
Grant ListK08 HD075831 / HD / NICHD NIH HHS / United States
K08HD075831 / HD / NICHD NIH HHS / United States