Assessing the Burden of Neonatal Abstinence Syndrome: Validation of ICD-9-CM Data, Florida, 2010-2011.

CONTEXT: 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. OBJECTIVE: 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. DESIGN: 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. RESULTS: 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. CONCLUSIONS: 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.

The Accuracy of Hospital Discharge Diagnosis Codes for Major Birth Defects: Evaluation of a Statewide Registry With Passive Case Ascertainment.

CONTEXT: Birth defects prevention, research, education, and support activities can be improved through surveillance systems that collect high-quality data. OBJECTIVE: To estimate the overall and defect-specific accuracy of Florida Birth Defects Registry (FBDR) data, describe reasons for false-positive diagnoses, and evaluate the impact of statewide case confirmation on frequencies and prevalence estimates. DESIGN: Retrospective cohort evaluation study. PARTICIPANTS: A total of 8479 infants born to Florida resident mothers between January 1, 2007, and December 31, 2011, and diagnosed with 1 of 13 major birth defects in the first year of life. MAIN OUTCOME MEASURES: Positive predictive value: calculated overall (proportion of FBDR-identified cases confirmed by medical record review, regardless of which of the 13 defects were confirmed) and defect-specific (proportion of FBDR-identified cases confirmed by medical record review with the same defect) indices. RESULTS: The FBDR's overall positive predictive value was 93.3% (95% confidence interval, 92.7-93.8); however, there was variation in accuracy across defects, with positive predictive values ranging from 96.0% for gastroschisis to 54.4% for reduction deformities of the lower limb. Analyses suggested that International Classification of Diseases, Ninth Edition, Clinical Modification, codes, upon which FBDR diagnoses are based, capture the general occurrence of a defect well but often fail to identify the specific defect with high accuracy. Most infants with false-positive diagnoses had some type of birth defect that was incorrectly documented or coded. If prevalence rates reported by the FBDR for these 13 defects were adjusted to incorporate statewide case confirmation, there would be an overall 6.2% rate reduction from 82.6 to 77.5 per 10 000 live births. CONCLUSIONS: A statewide birth defects surveillance system, relying on linkage of administrative databases, is capable of achieving high accuracy (>93%) for identifying infants with any one of the 13 major defects included in this study. However, the level of accuracy and the ability to minimize false-positive diagnoses vary depending on the defect.

Infant and maternal characteristics in neonatal abstinence syndrome--selected hospitals in Florida, 2010-2011.

Neonatal abstinence syndrome (NAS) is a constellation of physiologic and neurobehavioral signs exhibited by newborns exposed to addictive prescription or illicit drugs taken by a mother during pregnancy. The number of hospital discharges of newborns diagnosed with NAS has increased more than 10-fold (from 0.4 to 4.4 discharges per 1,000 live births) in Florida since 1995, far exceeding the three-fold increase observed nationally. In February 2014, the Florida Department of Health requested the assistance of CDC to 1) assess the accuracy and validity of using Florida's hospital inpatient discharge data, linked to birth and infant death certificates, as a means of NAS surveillance and 2) describe the characteristics of infants with NAS and their mothers. This report focuses only on objective two, describing maternal and infant characteristics in the 242 confirmed NAS cases identified in three Florida hospitals during a 2-year period (2010-2011). Infants with NAS experienced serious medical complications, with 97.1% being admitted to an intensive care unit, and had prolonged hospital stays, with a mean duration of 26.1 days. The findings of this investigation underscore the important public health problem of NAS and add to current knowledge on the characteristics of these mothers and infants. Effective June 2014, NAS is now a mandatory reportable condition in Florida. Interventions are also needed to 1) increase the number and use of community resources available to drug-abusing and drug-dependent women of reproductive age, 2) improve drug addiction counseling and rehabilitation referral and documentation policies, and 3) link women to these resources before or earlier in pregnancy.

Associations between exposure to ambient benzene and PM(2.5) during pregnancy and the risk of selected birth defects in offspring.

OBJECTIVE: A growing number of studies have investigated the association between air pollution and the risk of birth defects, but results are inconsistent. The objective of this study was to examine whether maternal exposure to ambient PM2.5 or benzene increases the risk of selected birth defects in Florida. METHODS: We conducted a retrospective cohort study of singleton infants born in Florida from 2000 to 2009. Isolated and non-isolated birth defect cases of critical congenital heart defects, orofacial clefts, and spina bifida were identified from the Florida Birth Defects Registry. Estimates of maternal exposures to PM2.5 and benzene for all case and non-case pregnancies were derived by aggregation of ambient measurement data, obtained from the US Environmental Protection Agency Air Quality System, during etiologically relevant time windows. Multivariable Poisson regression was used to estimate adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) for each quartile of air pollutant exposure. RESULTS: Compared to the first quartile of PM2.5 exposure, higher levels of exposure were associated with an increased risk of non-isolated truncus arteriosus (aPR4th Quartile, 8.80; 95% CI, 1.11-69.50), total anomalous pulmonary venous return (aPR2nd Quartile, 5.00; 95% CI, 1.10-22.84), coarctation of the aorta (aPR4th Quartile, 1.72; 95% CI, 1.15-2.57; aPR3rd Quartile, 1.60; 95% CI, 1.07-2.41), interrupted aortic arch (aPR4th Quartile, 5.50; 95% CI, 1.22-24.82), and isolated and non-isolated any critical congenital heart defect (aPR3rd Quartile, 1.13; 95% CI, 1.02-1.25; aPR4th Quartile, 1.33; 95% CI, 1.07-1.65). Mothers with the highest level of exposure to benzene were more likely to deliver an infant with an isolated cleft palate (aPR4th Quartile, 1.52; 95% CI, 1.13-2.04) or any orofacial cleft (aPR4th Quartile, 1.29; 95% CI, 1.08-1.56). An inverse association was observed between exposure to benzene and non-isolated pulmonary atresia (aPR4th Quartile, 0.19; 95% CI, 0.04-0.84). CONCLUSION: Our results suggest a few associations between exposure to ambient PM2.5 or benzene and specific birth defects in Florida. However, many related comparisons showed no association. Hence, it remains unclear whether associations are clinically significant or can be causally related to air pollution exposures.

Hospitalizations, costs, and mortality among infants with critical congenital heart disease: how important is timely detection?

BACKGROUND: Critical congenital heart disease (CCHD) was recently added to the U.S. Recommended Uniform Screening Panel for newborns. States considering screening requirements may want more information about the potential impact of screening. This study examined potentially avoidable mortality among infants with late detected CCHD and assessed whether late detection was associated with increased hospital resource use during infancy. METHODS: This was a state-wide, population-based, observational study of infants with CCHD (n = 3603) born 1998 to 2007 identified by the Florida Birth Defects Registry. We examined 12 CCHD conditions that are targets of newborn screening. Late detection was defined as CCHD diagnosis after the birth hospitalization. Deaths potentially avoidable through screening were defined as those that occurred outside a hospital following birth hospitalization discharge and those that occurred within 3 days of an emergency readmission. RESULTS: For 23% (n = 825) of infants, CCHD was not detected during the birth hospitalization. Death occurred among 20% (n = 568/2,778) of infants with timely detected CCHD and 8% (n = 66/825) of infants with late detected CCHD, unadjusted for clinical characteristics. Potentially preventable deaths occurred in 1.8% (n = 15/825) of infants with late detected CCHD (0.4% of all infants with CCHD). In multivariable models adjusted for selected characteristics, late CCHD detection was significantly associated with 52% more admissions, 18% more hospitalized days, and 35% higher inpatient costs during infancy. CONCLUSION: Increased CCHD detection at birth hospitals through screening may lead to decreased hospital costs and avoid some deaths during infancy. Additional studies conducted after screening implementation are needed to confirm these findings.

Maternal pre-pregnancy body mass index and risk of selected birth defects: evidence of a dose-response relationship.

BACKGROUND: This study investigates the relationship between maternal pre-pregnancy body mass index (BMI) and 26 birth defects identified through the Florida Birth Defects Registry. METHODS: Pre-pregnancy BMI (kg/m(2)) was categorised into underweight (<18.5), normal weight (18.5-24.9), overweight (25.0-29.9), and obese (≥30.0) among Florida resident mothers without pre-gestational diabetes who gave birth to singleton infants from March 2004 through December 2009. Obesity was classified as obese I (30.0-34.9), obese II (35.0-39.9), and obese III (≥40.0). Logistic regression was used to calculate the adjusted odds ratios and 95% confidence interval, representing the association between pre-pregnancy BMI and each of the 26 specific birth defects (and an 'any birth defect' composite). Models were adjusted for maternal age, race/ethnicity, education, smoking, marital status, and nativity. RESULTS: The livebirth prevalence of any birth defect increased with increasing BMI, from 3.9% among underweight women to 5.3% among obese III women (P < 0.001). Results show a direct dose-response relationship between maternal pre-pregnancy BMI and 10 defects under study (cleft palate without cleft lip, diaphragmatic hernia, hydrocephalus without spina bifida, hypoplastic left heart syndrome, pulmonary valve atresia and stenosis, pyloric stenosis, rectal and large intestinal atresia/stenosis, transposition of great arteries, tetralogy of Fallot, and ventricular septal defects) and the 'any birth defect' category. Conversely, gastroschisis exhibited a statistically significant inverse relationship with pre-pregnancy BMI. CONCLUSIONS: This study provides evidence of the increasing risk of birth defect-affected pregnancy with increasing pre-pregnancy obesity. Reducing pre-pregnancy obesity, even among obese women, may reduce the occurrence of birth defects.

Birth defects surveillance in Florida: infant death certificates as a case ascertainment source.

BACKGROUND: Completeness of case ascertainment is a concern for all birth defects registries and generally requires a multisource approach. Using infant death certificates as one case ascertainment source may identify cases of birth defects that would have otherwise been missed. We sought to examine the utility of adding infant death certificates to the Florida Birth Defect Registry's (FBDR) case ascertainment methods and to determine what factors are associated with the registry's failure to capture infants that die from birth defects. METHODS: FBDR cases from 1999 to 2006 were matched to a statewide linked birth-infant death file. Descriptive statistics were used to assess the FBDR's ability to capture infants with a birth defect-related cause of death (COD) and identify conditions most commonly missed. Factors associated with the FBDR's failure to capture an infant who died from a birth defect during the first year of life were identified with logistic regression models. RESULTS: There were 2558 (21.1%) infant deaths with birth defects listed as the underlying or an associated COD, of which the FBDR captured 73.3%. Most often missed defects included malformation of the coronary vessels, lung hypoplasia/dysplasia, anencephaly, and unspecified congenital malformations. Logistic regression identified gestational age/birth weight, age at death, autopsy decision, plurality, adequacy of prenatal care, and maternal nativity as factors associated with the FBDR's failure to capture an infant with a birth defect-related COD. CONCLUSIONS: Although the overall potential contribution of infant death certificates to the FBDR is small, this source contributes to the prevalence of specific defects.

Uncertainty in maternal exposures to ambient PM2.5 and benzene during pregnancy: Sensitivity to exposure estimation decisions.

We investigate uncertainty in estimates of pregnant women's exposure to ambient PM2.5 and benzene derived from central-site monitoring data. Through a study of live births in Florida during 2000-2009, we discuss the selection of spatial and temporal scales of analysis, limiting distances, and aggregation method. We estimate exposure concentrations and classify exposure for a range of alternatives, and compare impacts. Estimated exposure concentrations were most sensitive to the temporal scale of analysis for PM2.5, with similar sensitivity to spatial scale for benzene. Using 1-12 versus 3-8 weeks of gestational age as the exposure window resulted in reclassification of exposure by at least one quartile for up to 37% of mothers for PM2.5 and 27% for benzene. The largest mean absolute differences in concentration resulting from any decision were 0.78 µg/m(3) and 0.44 ppbC, respectively. No bias toward systematically higher or lower estimates was found between choices for any decision.

Improving the Completeness of Ascertainment in Florida's Birth Defects Surveillance Program: The Impact of Adding Infant Death and Emergency Department Data.

INTRODUCTION: The Florida Birth Defects Registry (FBDR) relies predominantly on a statewide, population-based, passive surveillance system constructed by linking together multiple administrative and clinical databases. With funding limitations and data restrictions a reality in public health, it is imperative for disease registries to have ongoing evaluation of existing and new data sources. This study quantifies the impact of expanding the FBDR case ascertainment net to include infant death certificates (IDCs) and emergency department (ED) discharge data on the reported prevalence of birth defects. METHODS: Between 2008 and 2011, the FBDR identified cases using various data sources: inpatient and outpatient discharge data (2008-2011), Regional Perinatal Intensive Care Center data (2008), Early Steps program data (2008), IDCs (2009-2011), and ED data (2010-2011). Using hypothetical reconstructions of the FBDR, we examined the overall and unique contribution of each data source in identifying infants with birth defects. This permitted evaluation of a changing FBDR data source mix during the 4-year study period. The effect of adding both IDCs and ED data was investigated by constructing the 2010-2011 FBDR with and without these data sources, and then comparing frequencies and prevalence rates across each scenario. Analyses were conducted for all FBDR cases and for specific birth defect categories; improvements in ascertainment were assessed across sociodemographic and perinatal characteristics. RESULTS: Overall, IDCs captured 3.4% of all infants with at least 1 birth defect studied, ED data captured 3.9% of the cases, and together the 2 data sources captured 7.2%. However, IDCs uniquely identified 0.8% of all cases, ED data uniquely identified 0.7% of all cases, and collectively they identified only 1.4% of cases that would otherwise have been missed. The unique contribution of IDC and ED data to case identification varied by defect and across sociodemographic and perinatal subgroups, with the largest impact among infants with anencephalus (64.7%), trisomy 13 (52.0%), trisomy 18 (22.2%), and encephalocele (13.3%), or those who were born weighing less than 1,500 grams or less than 32 weeks' gestation, or whose mothers' education was eighth grade or less. DISCUSSION: Although their unique contribution is small when all defects are considered together, IDCs and ED data contribute cases that would otherwise have been disproportionately lost and are thus an important addition to surveillance activities. The FBDR continues to strive to create a comprehensive, accurate, and efficient statewide birth defects surveillance system.

Evaluating Difficult Decisions in Public Health Surveillance: Striking the Right Balance between Timeliness and Completeness.

INTRODUCTION: State-based surveillance programs play a key role in birth defects planning, prevention, education, support, and research activities. High-quality data are essential to all of these functions, and a key indicator of quality is timeliness. The Florida Birth Defects Registry (FBDR)-one of the largest population-based state registries in the United States-faces challenges with timeliness, as evidenced by its 18-month lag time. The goal of this study was to determine if the timeliness of the FBDR could be improved without significantly reducing the completeness of birth defect ascertainment. METHODS: Using 2006-2011 data from the FBDR, we first investigated the timing of diagnosis of birth defects by estimating the effect of different periods of follow-up on prevalence rates reported by the FBDR. We achieved this through retrospective reconstructions of the FBDR under 5 different scenarios with progressively narrower follow-up windows for each infant, and by comparing recalculated rates to the rate of the current FBDR with 1 year of follow-up. We then considered scenarios in which the time lag used to construct the FBDR was reduced (15, 12, 9, and 6 months) by using less data (from 7 to 4 quarters). Recalculated rates were again compared to the current FBDR constructed with 2 years of data and an 18-month lag. Analyses were performed overall and for 44 specific defects. RESULTS: During the 6-year study period, the FBDR identified more than 27,000 infants with a defect detected during the first year of life. Restricting follow-up from 1 year to 9 months would only result in a loss of 1.4% of cases. Cutting follow-up in half to 6 months would miss 3.2% of cases, although there was significant variation across defects. Improving timeliness had a small impact on completeness of ascertainment. Overall, compiling the FBDR with only 6 quarters of Florida Agency for Health Care Administration data (as opposed to 8 quarters) would improve timeliness by approximately 6 months, resulting in a registry that is 99.4% complete. DISCUSSION: Six-to-nine month improvements in timeliness were achievable with a minimal sacrifice in completeness (0.6%-1.7%). Efforts to enhance data quality through the assessment of timeliness and completeness indicators are not unique to birth defects surveillance programs. Other programs, particularly those with similar passive case ascertainment protocols, can use our findings to consider a more timely release of registry data, or to design similar investigations of their own.

Factors associated with late detection of critical congenital heart disease in newborns.

OBJECTIVES: Critical congenital heart disease (CCHD) was recently added to the US Recommended Uniform Screening Panel for newborns. This study assessed whether maternal/household and infant characteristics were associated with late CCHD detection. METHODS: This was a statewide, population-based, retrospective, observational study of infants with CCHD born between 1998 and 2007 identified by using the Florida Birth Defects Registry. We examined 12 CCHD conditions that are primary and secondary targets of newborn CCHD screening using pulse oximetry. We used Poisson regression models to analyze associations between selected characteristics (eg, CCHD type, birth hospital nursery level [highest level available in the hospital]) and late CCHD detection (defined as diagnosis after the birth hospitalization). RESULTS: Of 3603 infants with CCHD and linked hospitalizations, CCHD was not detected during the birth hospitalization for 22.9% (n = 825) of infants. The likelihood of late detection varied by CCHD condition. Infants born in a birth hospital with a level I nursery only (adjusted prevalence ratio: 1.9 [95% confidence interval: 1.6-2.2]) or level II nursery (adjusted prevalence ratio: 1.5 [95% confidence interval: 1.3-1.7]) were significantly more likely to have late-detected CCHD compared with infants born in a birth hospital with a level III (highest) nursery. CONCLUSIONS: After controlling for the selected characteristics, hospital nursery level seems to have an independent association with late CCHD detection. Thus, perhaps universal newborn screening for CCHD could be particularly beneficial in level I and II nurseries and may reduce differences in the frequency of late diagnosis between birth hospital facilities.

A comparison of two surveillance strategies for selected birth defects in Florida.

OBJECTIVE: We linked data from two independent birth defects surveillance systems with different case-finding methods in an overlapping geographic area to assess Florida's suveillance of birth defects (e.g., neural tube defects, orofacial clefts, gastroschisis/omphalocele, and chromosomal defects), focusing on sensitivity and completeness of ascertainment measures. METHODS: Live-born infants identified from each system born during 2003-2006 in a nine-county catchment area with specific birth defects were linked to birth certificates. Using the enhanced surveillance system as a gold standard, we calculated the sensitivity of the Florida Birth Defects Registry (FBDR) for identifying infants. Next, we used capture-recapture models to estimate the completeness of case ascertainment and the prevalence of each birth defect in the catchment area. We used multivariable logistic regression models with backward elimination to estimate adjusted odds ratios and 95% confidence intervals for factors significantly associated with the FBDR's failure to capture infants ultimately identified by enhanced surveillance. RESULTS: The FBDR's sensitivity was 89.3%, and the overall completeness of ascertainment was estimated as 86.6%. Defect-specific sensitivity and completeness of ascertainment varied significantly by defect. The combined defect-specific sensitivity for all malformations under study was 86.6%; completeness of ascertainment ranged from 45.6% for anencephaly to 88.6% for Down syndrome, 87.9% for spina bifida without anencephaly, and 87.0% for orofacial clefts. CONCLUSIONS: For the defects under study, the FBDR captured nearly nine of every 10 infants born with selected birth defects. However, the FBDR's ability to identify specific defects was both more limited and defect dependent with widely varying defect-specific sensitivities.

The relative contribution of data sources to a birth defects registry utilizing passive multisource ascertainment methods: does a smaller birth defects case ascertainment net lead to overall or disproportionate loss?

Since 1998, the Florida Department of Health (FDOH) has operated the Florida Birth Defects Registry (FBDR), a statewide, population-based, passive surveillance system. Cases are identified by collecting information from extant data sources including the statewide hospital inpatient and ambulatory discharge data sets. Additional data sources include administrative, clinical, and service-related information from the FDOH's Children's Medical Services program for children with special health care needs. Like many state birth defects programs, the FBDR faces diminishing funding and resources that may restrict the registry to hospital discharge data. We conducted an evaluation to quantify the potential under-ascertainment to the FBDR resulting from loss of specific data sources, and to determine if there would be a disproportionate loss of cases by sociodemographic and perinatal characteristics. Analyses involved a series of retrospective reconstructions of the FBDR for 1998-2007 to assess the number of cases that would have been ascertained and reported based on the hypothetical loss of 1 or more of the FBDR source data sets. The reconstructed number of cases identified for each defect category was then compared to the current FBDR (constructed using all 5 source data sets) to determine the proportion of cases that would have been missed if the data sources in question were eliminated. These scenarios were constructed overall and by selected characteristics to identify potential disparities in the proportion of cases missed. The inpatient hospital discharge data set was the primary data source for identification of birth defects in the FBDR. Elimination of this single data source would cause the FBDR to miss nearly three fourths of infants diagnosed with 1 or more of the birth defects under study. Our evaluation revealed that an FBDR constructed on hospital discharge data alone would disproportionately miss more cases born to subgroups of women, including non-Hispanic blacks, Hispanics, and those born outside the US. Despite funding and resource constraints, the FBDR continues efforts to identify data sources that may contribute to completeness of case ascertainment in an effort to serve the needs of the Florida maternal and child health population.

Developing a database management system to support birth defects surveillance in Florida.

The value of any public health surveillance program is derived from the ways in which data are managed and used to improve the public's health. Although birth defects surveillance programs vary in their case volume, budgets, staff, and objectives, the capacity to operate efficiently and maximize resources remains critical to long-term survival. The development of a fully-integrated relational database management system (DBMS) can enrich a surveillance program's data and improve efficiency. To build upon the Florida Birth Defects Registry--a statewide registry relying solely on linkage of administrative datasets and unconfirmed diagnosis codes-the Florida Department of Health provided funding to the University of South Florida to develop and pilot an enhanced surveillance system in targeted areas with a more comprehensive approach to case identification and diagnosis confirmation. To manage operational and administrative complexities, a DBMS was developed, capable of managing transmission of project data from multiple sources, tracking abstractor time during record reviews, offering tools for defect coding and case classification, and providing reports to DBMS users. Since its inception, the DBMS has been used as part of our surveillance projects to guide the receipt of over 200 case lists and review of 12,924 fetuses and infants (with associated maternal records) suspected of having selected birth defects in over 90 birthing and transfer facilities in Florida. The DBMS has provided both anticipated and unexpected benefits. Automation of the processes for managing incoming case lists has reduced clerical workload considerably, while improving accuracy of working lists for field abstraction. Data quality has improved through more effective use of internal edits and comparisons with values for other data elements, while simultaneously increasing abstractor efficiency in completion of case abstraction. We anticipate continual enhancement to the DBMS in the future. While we have focused on enhancing the capacity of our DBMS for birth defects surveillance, many of the tools and approaches we have developed translate directly to other public health and clinical registries.

Ascertainment of gastroschisis using the ICD-9-CM surgical procedure code.

OBJECTIVE: To determine the effectiveness of using the ICD-9-CM procedure code 54.71 for case ascertainment of gastroschisis. METHODS: Using procedure code 54.71, we queried a statewide hospital discharge database to identify all cases coded as undergoing surgical repair of gastroschisis. Each retrieved case was verified as having gastroschisis by review of the hospital record. All gastroschisis cases were then matched to the Florida Birth Defect Registry (FBDR) dataset. This registry uses a passive system of multiple data sources and employs the ICD-9-CM diagnostic code 756.79 to identify gastroschisis and other abdominal wall defects. RESULTS: Of 93 cases identified by using code 54.71, 92 were confirmed by record review to have gastroschisis. The FBDR identified 87 of the 92 cases (95%). The FBDR missed three of the remaining five cases because of linkage difficulties between inconsistent data elements in the respective data files. The other two cases were not identified by the FBDR because the source database (AHCA discharge) truncates the entry of ICD-9-CM diagnostic codes when more than 10 of them are listed in the medical record. CONCLUSIONS: Use of the surgical procedure code was demonstrated to be superior to the diagnostic code as a method for identification of gastroschisis cases. The same approach may be useful in the detection of malformations other than gastroschisis.