https://orcid.org/0009-0000-9353-5941
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Abstract
Purpose
This study aimed to systematically evaluate the validity of variables related to pregnancy, delivery, and key characteristics of the infant in the Danish National Patient Register using maternal medical records as the reference standard.
Patients and Methods
We reviewed medical records of 1264 women giving birth in the Region of Southern Denmark during 2017. We calculated positive (PPV) and negative (NPV) predictive values, sensitivity, and specificity to estimate the validity of 49 selected variables.
Results
The PPV was ≥0.90 on most pregnancy-related variables including parity, pre-gestational BMI, diabetes disorders, and previous cesarean section, while it was lower for hypertensive disorders, especially mild to moderate preeclampsia (0.49, 95% CI 0.32–0.66). Sensitivity ranged from 0.80 to 1.00 on all pregnancy-related variables, except hypertensive disorders (sensitivity 0.38–0.71, lowest for severe preeclampsia). On most delivery-related variables including obstetric surgical procedures (eg cesarean section and induction of labor), pharmacological pain-relief, and gestational age at delivery, PPV’s ranged from 0.98 to 1.00 and the corresponding sensitivities from 0.87 to 1.00. Regarding infant-related variables, both the APGAR score registered five minutes after delivery and birthweight yielded a PPV of 1.00.
Conclusion
Obstetric coding in the Danish National Patient Register shows very high validity and completeness making it a valuable source for epidemiologic research.
Plain Language Summary
Danish register data are often used for epidemiological research in reproduction. The registers are based on coded information to the registers based on information from medical records. The quality of the register data is highly dependent of the validity of the codes. Yet there is a lack in our knowledge of the validity of data related to pregnancy, childbirth, and the characteristics of the newborn baby. We therefore aimed to validate the Danish National Patient Registry data related to pregnancy and childbirth by comparing the registered code with information from the medical records.
We scrutinized medical records from 1264 women giving birth in the Region of Southern Denmark during 2017. We compared the registration in the medical record with the registered code in the Danish National Patient Registry by calculating how accurate the register data are according to 49 different variables.
Results showed that registered codes in the Patient Registry for pregnancy- and childbirth-related conditions and key infant characteristics were to a high degree in agreement with the data from the medical report with few exceptions.
In conclusion, the study revealed that the Danish National Patient Register provides highly accurate and comprehensive data for most pregnancy, delivery, and infant-related variables. This underscores the register's value as a reliable source for epidemiologic research in reproductive health.
Abbreviations
PPV, Positive predictive value; NPV, Negative predictive value; BMI, Body mass index.
Ethical Approval
Permission to access medical journals was obtained from the Region of Southern Denmark (21/49588, October 6, 2021). The use of data from the national registers was approved by the Danish Data Protection Agency (FSEID-00004511). Due to Danish legislation, approval from Ethics Committee was not needed.
Acknowledgments
We would like to thank Emma Simonsen, Maria H. Stoltz-Andersen, Sophie Lund Elkrog, and Debbie Rosenlyst Ollerup for their work on entering data into REDCap.
Author Contributions
All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.
Disclosure
The authors report no financial or non-financial conflicts of interest in this work.