Agreement between patients' self-report and physicians' prescriptions on cardiovascular drug exposure: the PGRx...

Patients' self-reported drug exposure is subjected to memory errors and different sources of bias. Utilization of prescription records is impaired with non-compliance and over-the-counter (OTC) drug utilization. This study compared patients' self-report (PS) to physician's prescriptions of cardiovascular drugs (CVDs).

The PGRx database is constituted by networks of specialized centers that recruited cases of 15 different diseases including myocardial infarction (MI) cases, and a network of general practitioners recruiting a pool of potential referents. For MI cases and referents, data on all drug utilization within the 2 years preceding the index date were obtained from PS and from physician's report of their prescriptions (PP). Patients' reports were obtained using a structured telephone interview complemented with an interview guide containing names of diseases and pictures of drug packages. Comparisons were made on exposure to each class of CVDs, for different time-windows, 2 months, 3-12 months and 13-24 months prior to the index date.

The concordance between physician and patient report was assessed on 2702 patient-physician pairs. Agreement was excellent overall (kappa = 0.83, 95% confidence interval (CI): 0.81-0.85). Prevalences of exposure were very close between PS and PP for all classes of prescription CVDs.

Using a standardized and systematic collection of information on drug exposure directly from patients appeared to provide similar information to using physician prescription records over a 2-year recall period.