Accuracy of Birth Certificate and Hospital Discharge Data: A Certified Nurse-Midwife and Physician Comparison
Heather Bradford, MSN, CNM, ARNP Vicky Cárdenas, PhD, MHS Mona T. Lydon-Rochelle, PhD, MPH, CNM University of Washington
Study Rationale
Birth certificate and hospital discharge data are relied upon heavily for surveillance and research Epidemiologic research is important in evaluating birth outcomes No previous study has examined variations in reporting accuracy by birth attendant
Birth Record Validation Study
10 WA State hospitals in 2000 Cesarean sections excluded 220 births attended by CNMs 2479 births attended by MDs Secondary analysis
Nurse-midwifery Births in America
10% of U.S. hospital vaginal births in 2003 delivered by CNMs CNMs attend 15% or more of vaginal births in 8 states Most CNM births occur in hospitals Women delivered by CNMs tend to:
Be socio-economically disadvantaged and from ethnic groups at high-risk Receive less interventions and procedures Have babies who are less likely to be pre-term and low birth weight
Comparison of True Positive Rates
Medical record as gold standard of accuracy Medical record was compared to:
birth certificate hospital discharge summary both sources combined
True positive rate (TPR) perfect score = 100%
Variables Examined
Maternal medical conditions:
Acute or chronic lung disease Established genital herpes
Gestational diabetes Pregnancy-induced hypertension
Pregnancy complications:
Intrapartum and postpartum events:
Premature rupture of membranes Labor augmentation Induction of labor Cephalopelvic disproportion Placental abruption Vaginal birth after cesarean Episiotomy Vaginal birth lacerations
Results
Characteristics of women and their newborns: CNMs vs. MDs
Women attended by CNMs more likely to be:
Younger, less likely to be married Non-White (except for Asian/Pacific Islander) Delivered in smaller volume hospital Covered by Medicaid
Newborns of women attended by CNMs:
More likely to be normal weight range Less likely to be pre-term
Accuracy of Medical Conditions
100
True Positive Rate (%)
80 60 40 20 0 Genital herpes (birth certificate) 45.0 29.9 Lung disease (hospital d/c) 23.1 16.0
CNMs MDs
Accuracy of Pregnancy Complications
100
True Positive Rate (%)
95 90 85 80
Gestational Diabetes (combined) 100.0 89.2
CNMs MDs
Variation in Accuracy of Pregnancy Complications
100 90 80 70 60 50 40 30 20 10 0
True Positive Rate (%)
PIH (birth certificate) 73.3 37.2
PIH (combined) 93.3 75.8
CNMs MDs
Variation in Accuracy of Intrapartum and Postpartum Events in Birth Certificate Data
100
True Positive Rate (%)
80 60 40 20 0
PROM 56 26.1 Augmentation 50.7 30.5 Induction 67.7 44.7 VBAC 100 66.7
CNMs MDs
Variation in Accuracy of Intrapartum and Postpartum Events in Combined Data
100
True Positive Rate (%)
80 60 40 20 0
Premature Rupture of Membranes 76 52.7
CNMs MDs
Accuracy of Intrapartum and Postpartum Events in Hospital Discharge Data
100
True Positive Rate (%)
80 60 40 20 0 CPD 100.0 81.7 Episiotomy 92.9 84.8 Lacerations 100.0 90.8
CNMs MDs
Accuracy of Intrapartum and Postpartum Events in Combined Data
100
True Positive Rate (%)
80 60 40 20 0
Induction CPD 100 84.1 Placental abruption 100 86.2
Episiotomy Lacerations 92.9 84.8 100 90.8
CNMs MDs
91.1 86
Why such variations?
Differences in clinician practice style Complexity of risk in patient case-mix Differences in patient volume load
Study Implications
Birth certificate and hospital discharge data is susceptible to information bias More rigorous attention needs to be given to optimizing quality improvement of recorded information More evaluation needed
Questions? hbradford@comcast.net