Medication use during pregnancy, gestational age and date of delivery: agreement between maternal self-reports and health database information in a cohort

Abstract

BackgroundHealth databases are a promising resource for epidemiological studies on medications safety during pregnancy. The reliability of information on medications exposure and pregnancy timing is a key methodological issue. This study (a) compared maternal self-reports and database information on medication use, gestational age, date of delivery; (b) quantified the degree of agreement between sources; (c) assessed predictors of agreement.MethodsPregnant women recruited in a prenatal clinic in Friuli Venezia Giulia (FVG) region, Italy, from 2007 to 2009, completed a questionnaire inquiring on medication use during pregnancy, gestational age and date of delivery. Redeemed prescriptions and birth certificate records were extracted from regional databases through record linkage. Percent agreement, Kappa coefficient, prevalence and bias-adjusted Kappa (PABAK) were calculated. Odds Ratio (OR), with 95 % confidence interval (95 % CI), of ≥1 agreement was calculated through unconditional logistic regression.ResultsThe cohort included 767 women, 39.8 % reported medication use, and 70.5 % were dispensed at least one medication. Kappa and PABAK indicated almost perfect to substantial agreement for antihypertensive medications (Kappa 0.86, PABAK 0.99), thyroid hormones (0.88, 0.98), antiepileptic medications (1.00, 1.00), antithrombotic agents (0.70, 0.96). PABAK value was greater than Kappa for medications such as insulin (Kappa 0.50, PABAK 0.99), antihistamines for systemic use (0.50, 0.99), progestogens (0.28, 0.79), and antibiotics (0.12, 0.63). Adjusted OR was 0.48 (95 % CI 0.26; 0.90) in ex- vs. never smokers, 0.64 (0.38; 1.08) in < high school vs. university, 1.55 (1.01; 2.37) in women with comorbidities, 2.25 (1.19; 4.26) in those aged 40+ vs. 30–34 years.Gestational age matched exactly in 85.2 % and date of delivery in 99.5 %.ConclusionsFor selected medications used for chronic conditions, the agreement between self-reports and dispensing data was high. For medications with low to very low prevalence of use, PABAK provides a more reliable measure of agreement. Maternal reports and dispensing data are complementary to each other to increase the reliability of information on the use of medications during pregnancy. Birth certificates provide reliable data on the timing of pregnancy. FVG health databases are a valuable source of data for pregnancy research.Electronic supplementary materialThe online version of this article (doi:10.1186/s12884-015-0745-3) contains supplementary material, which is available to authorized users.

Agreement Between Maternal Report and Medical Records During Pregnancy: Medications for Rheumatoid Arthritis and Asthma

“…Non‐differential exposure misclassification tends to bias associations toward the null, which could diminish an association indicative of a harmful medication effect. Several studies have compared medication exposure information from various data sources during pregnancy; however, agreement between maternal report and medical records is largely unknown . One study compared maternal report with active prescription medications listed in electronic medical records and reported generally higher agreement for medications indicated for chronic conditions compared with sporadically used medications .…”

How to Improve Information on Medication Exposure during Pregnancy

“…The authors demonstrate that agreement was higher for medications taken continuously compared to medications used sporadically, which is in line with an Italian study by Pisa and colleagues. 5 The discrepancy between maternal report and medical records has also been noted for prescribed drug register data, where similar patterns are observed between drugs used continuously versus those used sporadically during pregnancy, 9 and variation exists by maternal disease. This highlights the importance of studying drug exposures by specific disease, and preferably as a collaboration with obstetricians and specialists.…”

“…The risk-benefit profile of medications used during pregnancy is assessed mostly on postauthori sation studies. 5 Women with chronic disease who previously were advised against having children today become pregnant to a larger extent. Hence, specialists and obstetricians now care for a new class of pregnant women, and the issue of disease, disease severity and the possible adverse medication effects is complicated.…”

“…Each method has its strengths, but also limitations with risk of ascertain ment bias and misclassification. 5 Prospectively collected data are always preferable to reduce bias due to recall. Some studies have reported data on the agreement between birth register or prescribed drug register information and maternal report drug use during pregnancy.…”

“…Some studies have reported data on the agreement between birth register or prescribed drug register information and maternal report drug use during pregnancy. 2,4,5,7,8 However, agreement between maternal report and medical records has been less studied. 9 In this issue of Paediatric and Perinatal Epidemiology, Palmsten and colleagues 10 report on the comparability of information on medication exposures for rheuma toid arthritis and asthma during pregnancy collected in prospective cohorts from maternal report and medical records.…”