On October 1, 2015, the United States transitioned from using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) to ICD-10-CM. Continuing to monitor the burden of neonatal abstinence syndrome (NAS) after the transition presently requires use of data dependent on ICD-9-CM coding to enable trend analyses. Little has been published on the validation of using ICD-9-CM codes to identify NAS cases.
To assess the validity of hospital discharge data (HDD) from selected Florida hospitals for passive NAS surveillance, based on ICD-9-CM codes, which are used to quantify baseline prevalence of NAS.
We reviewed infant and maternal data for all births at 3 Florida hospitals from 2010 to 2011. Potential NAS cases included infants with ICD-9-CM discharge codes 779.5 and/or 760.72 in linked administrative data (ie, HDD linked to vital records) or in unlinked HDD and infants identified through review of neonatal intensive care unit admission logs or inpatient pharmacy records. Confirmed infant cases met 3 clinician-proposed criteria. Sensitivity and positive predictive value were calculated to assess validity for the 2 ICD-9-CM codes, individually and combined.
Of 157 confirmed cases, 134 with 779.5 and/or 760.72 codes were captured in linked HDD (sensitivity = 85.4%) and 151 in unlinked HDD (sensitivity = 96.2%). Positive predictive value was 74.9% for linked HDD and 75.5% for unlinked HDD. For either HDD types, the single 779.5 code had the highest positive predictive value (86%), lowest number of false positives, and good to excellent sensitivity.
Passive surveillance using ICD-9-CM code 779.5 in either linked or unlinked HDD identified NAS cases with reasonable validity. Our work supports the use of ICD-9-CM code 779.5 to assess the baseline prevalence of NAS through 2015.
Division of Reproductive Health, National Center for Chronic Disease Prevention and Health Promotion, Atlanta, Georgia (Drs Phillips-Bell and Petersen); Division of Community Health Promotion, Florida Department of Health, Tallahassee, Florida (Dr Phillips-Bell and Ms Holicky); Centers for Disease Control and Prevention/Council of State and Territorial Epidemiologists Applied Epidemiology Fellowship, Atlanta, Georgia (Ms Holicky); Division of Congenital and Developmental Disorders, National Center on Birth Defects and Developmental Disabilities, Centers for Disease Control and Prevention, Atlanta, Georgia (Dr Lind); Department of Community and Family Health, The Chiles Center, College of Public Health, University of South Florida, Tampa, Florida (Dr Sappenfield); Department of Pediatrics, University of Florida College of Medicine—Jacksonville, Jacksonville, Florida (Dr Hudak); Public Health Research Unit, Division of Community Health Promotion, Florida Department of Health, Tallahassee, Florida (Mss Anjorhin and Correia and Dr Watkins); and Department of International Health, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland (Dr Creanga).
Correspondence: Ghasi S. Phillips-Bell, ScD, MS, Division of Community Health Promotion, Florida Department of Health, 4052 Bald Cypress Way, Bin A13, Tallahassee, FL 32399 (Ghasi.Phillips-Bell@flhealth.gov).
The authors acknowledge the following: Statewide Task Force on Prescription Drug Abuse and Newborns. Florida Office of the Attorney General. John H. Armstrong, MD; Celeste Philip, MD, MPH; Anna Likos, MD; Carina Blackmore, DVM, PhD; Philip Cavicchia, PhD, MSPH; Cheryl L. Clark, DrPH; Marie Bailey, MA, MSW; Karen Freeman, MPH, MS; Heather Lake-Burger, MS, MPH, Florida Department of Health. Diana Sampat, MPH, University of South Florida Birth Defects Surveillance Program. Leonard J. Paulozzi, MD, National Center for Injury Prevention and Control, CDC. John Curran, MD, University of South Florida. Philip A. Lederer, MD, Centers for Disease Control and Prevention Epidemic Intelligence Service Program. Robert W. Yelverton, MD, American Congress of Obstetricians and Gynecologists. The staff at the participating hospitals in Florida. This study/report was supported in part by an appointment to the Applied Epidemiology Fellowship Program administered by the Council of State and Territorial Epidemiologists (CSTE) and funded by the Centers for Disease Control and Prevention Cooperative Agreement Number 1U38OT000143-03.
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention, the Florida Department of Health, or any other organization.
The authors declare no conflicts of interest.
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