Proportion of critical congenital heart defects attributable to unhealthy prepregnancy body mass index among women with live births in Florida, 2005-2016.

BACKGROUND: Associations between maternal prepregnancy body mass index (BMI) and congenital heart defects have been reported, however, the proportion of critical congenital heart defects (CCHDs) attributable to unhealthy prepregnancy BMI has not been determined. Our objective was to investigate the association between maternal prepregnancy BMI and CCHDs. METHODS: The Florida Birth Defects Registry was used to identify infants with CCHDs born between 2005-2016. Birth certificate data were used to define the source population and identify perinatal and socio-demographic characteristics. BMI values were categorized as underweight (<18.5), normal weight (18.5-24.9), overweight (25.0-29.9), obese I (30.0-34.9), obese II (35.0-39.9), and obese III (≥40.0). Multi-predictor logistic regression models were used to estimate adjusted odds ratios (aORs) and 99% confidence intervals representing the association between maternal prepregnancy BMI and CCHDs. Adjusted population attributable fractions (PAFs) for the aORs were calculated. RESULTS: We observed a significantly increased risk of "any CCHD" in infants born to women at any level of obesity. Among the 12 CCHDs examined, 5 showed a significantly increased risk among mothers in the two highest obesity levels (II & III). Approximately 8% of all CCHDs may be attributed to suboptimal maternal prepregnancy BMI, with the highest total individual CCHD PAFs for pulmonary valve atresia (21.7%) and total anomalous pulmonary venous return (12.8%). CONCLUSIONS: Women with suboptimal prepregnancy BMI are at increased odds of having a child born with a CCHD. We found evidence of a direct dose-response relationship between prepregnancy BMI and odds for CCHD; with variation by CCHD subtype.

Evaluation of the Sensitivity and Accuracy of Birth Defects Indicators on the 2003 Revision of the U.S. Birth Certificate: Has Data Quality Improved?

BACKGROUND: The 2003 revision of the U.S. Birth Certificate was restricted to birth defects readily identifiable at birth. Despite being the lone source of birth defects cases in some studies, we lack population-based information on the quality of birth defects data from the most recent revision of the birth certificate. METHODS: We linked birth certificate data to confirmed cases from the Florida Birth Defects Registry (FBDR) to assess the sensitivity and positive predictive value (PPV) of birth defects indicators on the birth certificate. Descriptive statistics and log-binomial regression were used to examine variation in data quality measures by defect type and other characteristics. We also evaluated the contribution of birth certificates as a case ascertainment source for the FBDR. RESULTS: Sensitivity of the birth certificate was poor (19.1%) with variation across defects ranging from 55% for anencephaly and 54% for gastroschisis, to <10% for other defects. PPV was better (87.1%) and ranged from >93% for orofacial clefts and gastroschisis to <55% for anencephaly and limb reduction defects. We also observed variation in data quality across maternal, infant, and hospital characteristics. Of cases identified by the birth certificate and not any other FBDR data source, 54.9% were false-positive diagnoses. CONCLUSIONS: Efforts to restrict the 2003 revision of the birth certificate to defects identifiable at birth have not improved the likelihood that birth certificates will identify infants born with those defects. We do not recommend the use of birth certificates as a source of birth defects data without case verification strategies.

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.

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.

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.