EMR data capture prescribed medications, although these prescriptions are not necessarily filled or taken 32 and, therefore, reflect physician-prescribing patterns more accurately than claims data, which capture prescription medications that are dispensed to the patient.
The medical care claims are linked to complete outpatient prescription drug claims, including claims for mail order prescriptions and specialty pharmacy, which fully capture prescription fills from all locations.
We propose that the most successful systems are those able to accurately and efficiently capture prescription and use data, can refresh information frequently, have easy access to experts for advanced statistical analyses, and have a large patient population from which to draw data.
Our cohort was restricted to women age 66 years or older to capture prescription drug records in the year prior and throughout the study period, which are available through the Ontario Drug Benefit (ODB) program for all individuals aged 65 years or older.
First and foremost, our data source only captures prescriptions filled by women in an outpatient setting.
We excluded laboratory tests where patients were hospitalized up to two days prior to their prescription date to ensure we captured prescriptions first initiated in the outpatient setting.
This would not have captured prescriptions given on hospital discharge, provided in outpatient or home care settings, or those previously "stockpiled" by the patient.
GPRD captures prescriptions issued to patients by general practitioners, and it also includes information on patient demographics, diagnoses, referrals, hospitalisations and laboratory test results.
PARC data have been used widely in research, although they do not capture private prescriptions for antibiotics (rare in Wales).
