Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Apr;24(4):381-8.
doi: 10.1002/pds.3740. Epub 2015 Feb 5.

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

Kelesitse Phiri  1 , Sonia Hernandez-Diaz, Lawrence C Tsen, Karen M Puopolo, John D Seeger, Brian T Bateman
Affiliations

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

Kelesitse Phiri et al. Pharmacoepidemiol Drug Saf. 2015 Apr.

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.

Keywords: ICD-9-CM codes; gestational age; healthcare records; pharmacoepidemiology; sensitivity; small for gestational age; specificity.

PubMed Disclaimer

Figures

Figure 1
Figure 1. Study source population
a Stillbirths were identified from the following ICD-9-CM diagnosis codes: 656.4x, v27.1, v27.3, v27.4, v27.6, and v27.7 b All deliveries from 2006 were deleted since > 80% of deliveries from that year had no diagnosis billing codes
Figure 2
Figure 2. Varying thresholds for defining SGAa for all deliveries (N = 51 292)
a SGA based on recorded birthweight and gestational age
See this image and copyright information in PMC

References

    1. Carberry AE, Gordon A, Bond DM, Hyett J, Raynes-Greenow CH, Jeffery HE. Customised versus population-based growth charts as a screening tool for detecting small for gestational age infants in low-risk pregnant women. Cochrane Database Syst Rev. 2011;(12):CD008549. doi:CD008549. - PubMed
    1. Saenger P, Czernichow P, Hughes I, Reiter EO. Small for gestational age: short stature and beyond. Endocr Rev. 2007;28:219–251. - PubMed
    1. La Merrill M, Stein CR, Landrigan P, Engel SM, Savitz DA. Prepregnancy body mass index, smoking during pregnancy, and infant birth weight. Ann Epidemiol. 2011;21:413–420. - PMC - PubMed
    1. Luyckx VA, Bertram JF, Brenner BM, et al. Effect of fetal and child health on kidney development and long-term risk of hypertension and kidney disease. Lancet. 2013;382:273–283. - PubMed
    1. Lim G, Tracey J, Boom N, et al. CIHI survey: Hospital costs for preterm and small-for-gestational age babies in Canada. Healthc Q. 2009;12:20–24. - PubMed

Publication types

LinkOut - more resources