Are You My Mother? A Validation of Clinical Practice Research Datalink (CPRD) Aurum Mother Baby Link

Background: Many important health concerns related to exposures in pregnant patients and effects on their offspring can only be answered using observational data; however, there are few large data resources with linkage between parents and their children with adequately long follow-up in both individuals. The CPRD GOLD Mother Baby Link (MBL) has been valuable for studies of exposures during pregnancy and outcomes in children. CPRD has created a MBL for their latest and larger data source, CPRD Aurum, using a similar method probabilistically linking birthing parents with their liveborn children. Assessments of the accuracy of the MBL are critical for research. This is the first validation study of the MBL.

Objectives: To validate mother-child pairs and to evaluate the accuracy of delivery dates recorded in CPRD Aurum MBL.

Methods: The study population was all available MBL pairs in a 100-practice sample of CPRD Aurum. We assessed the validity of the MBL linkage via a questionnaire sent to general practitioners (GPs) of a sample of MBL patients asking if the MBL pair was correct. We also evaluated the accuracy of the algorithm-derived MBL delivery date in three ways: 1) as part of the questionnaire asking if the delivery date was correct within 14 days, 2) compared to the matched child’s birth month recorded in CPRD Aurum, and 3) MBL delivery date was compared to the birthing parent’s HES delivery date in those with Hospital Episode Statistics Admitted Patient Care (HES) linkage.

Results: There were 124,962 MBL pairs: 124,962 livebirths matched to 91,218 birthing parents in the study population. Based on 361 questionnaire responses standardized to the full study population, 85% (95% CI 74%-96%) of pairs were confirmed as correctly matched, < 1% (95% CI 0.04%-1.4%) incorrectly matched, and 13% (95% CI 10%-18%) could not be confirmed. For 71% of the questionnaire sample, the delivery date was confirmed by a GP as correct within 14 days, 15% incorrect, and 13% not confirmed. Among the entire population of 124,962 MBL pairs, 73% had MBL delivery date within the baby’s birth month recorded in CPRD Aurum. Among 79,834 birthing patients with HES linkage, 79% of 107,080 MBL deliveries in CPRD Aurum were correct within 14 days compared to in HES.

Conclusions: These results indicate that the great majority of CPRD Aurum MBL pairs were correctly matched and most recorded delivery dates were correct within 14 days. Information on how researchers can further refine MBL delivery dates and potential sources of selection bias in the MBL will be presented. CPRD Aurum is larger and has more currently enrolled patients than CPRD GOLD, thus its MBL may be valuable for studies of the effects of new or uncommonly used drugs or of rare outcomes in pregnancy.