Self-reported data on medicine use in the Norwegian Mother and Child cohort study compared to data from the Norwegian Prescription Database

Abstract

Aims: To study information on prescribed drug use (opioids, antidepressants and benzodiazepines (BZD)) recorded in the Norwegian Prescription Database (NorPD) and to compare this information with selfreported drug use among pregnant women in the Norwegian Mother and Child Cohort Study (MoBa).

Materials and methods: The study population consisted of 28 479 women who participated in MoBa and who answered all questionnaires in pregnancy and whose pregnancy started after 1 March 2004. Data on dispensed drugs in NorPD were extracted for three different time windows: a) the pregnancy period, b) 30 days prior to pregnancy in addition to pregnancy, c) 60 days prior to pregnancy in addition to pregnancy. Data on self- reported drug use in MoBa were used as the reference standard in the validity analysis. Sensitivity and specificity were calculated.

Results: Sensitivity of drug use as recorded in NorPD for the pregnancy period was highest for antidepressants (66.9%) and BZD-antiepileptics (100%) and lowest for BZD-anxiolytics (44.8%) and BZDhypnotics (27.8%). Expansion of the time windows for dispensed drugs in the NorPD to include intervals 30 and 60 days before pregnancy led to higher sensitivity, but lower specificity of all classes of drugs. For opioids, sensitivity increased from 48.8% to 53.6%, while specificity decreased from 98.7 to 97.6%. For antidepressants and BZD-anxiolytics, specificity decreased for both from 99.7 to 99.4%.

Conclusion: Using self-reported data as reference standard, the prescription data provides valid information on current exposures to BZD-antiepileptics and antidepressants in pregnant women if time windows are selected with adequate consideration depending on the investigated problem. However, validity is lower for other benzodiazepines and opioids.