Record linkage to obtain birth outcomes for the evaluation of screening biomarkers in pregnancy: a feasibility study

Maternal serum levels of PAPP-A and free β-hCG for 1882 women randomly selected from a pathology database in New South Wales (NSW) were linked to routinely collected birth and hospital databases. Crude relative risks were calculated to investigate the association between low levels (multiples of the median ≤ 5th percentile) of PAPP-A or free β-hCG and the outcomes of preterm delivery (<37 weeks), small for gestational age (<10th percentile), fetal loss and stillbirth.Using only full name, sex and date of birth for record linkage, pregnancy outcomes were available for 1681 (89.3%) of women included in the study. Low levels of PAPP-A had a stronger association with adverse pregnancy outcomes than a low level of free β-hCG which is consistent with results in published studies. The relative risk of having a preterm birth with a low maternal serum PAPP-A level was 3.44 (95% CI 1.96–6.10) and a low free β-hCG level was 1.31 (95% CI 0.55–6.16).This study provides data to support the use of record linkage for outcome ascertainment in studies evaluating predictive tests. Linkage proportions are likely to increase if more personal identifiers are available. This method of follow-up is a cost-efficient technique and can now be applied to a larger cohort of women.Routinely collected data or population-health datasets (PHDS) have been used to address key issues in health. The population coverage and accessibility make PHDS an attractive and cost effective resource for research allowing description of the total burden of disease in the population, assessment of risk factors and casual pathways[1] and investigation of rare outcomes[2]. Linkage of population health data to pathology data is a new approach for evaluating predictive tests that is potentially more efficient and efficacious than current methods. Traditional methods for evaluation of predictive tests require evaluation in a representative spectrum of patients, and complete follow-up.[3] Such studies are often performed