Comparison of prescription and medical records in reflecting patient antihypertensive drug therapy.

OBJECTIVE: To determine the completeness of prescription records, and the extent to which they agreed with medical record drug entries for antihypertensive medications.
SETTING: Three clinics affiliated with two staff model health maintenance organizations (HMOs). PARTICIPANTS: Randomly selected HMO enrollees (n = 982) with diagnosed hypertension.
METHODS: Computer-based prescription records for antihypertensive medications were reviewed at each location using an algorithm to convert the directions-for-use codes into an amount to be consumed per day (prescribed daily dosage). The medical record was analyzed similarly for the presence of drug notations and directions for use.
RESULTS: There was a high level of agreement between the medical record and prescription file with respect to identifying the drug prescribed by drug name. Between 5 and 14 percent of medical record drug entries did not have corresponding prescription records, probably reflecting patient decisions not to have prescriptions filled at HMO-affiliated pharmacies or at all. Further, 5-8 percent of dispensed prescription records did not have corresponding medical record drug entry notations, probably reflecting incomplete recording of drug information on the medical record. The percentage of agreement of medical records on dosage ranged from 68 to 70 percent across two sites. Approximately 14 percent of drug records at one location and 21 percent of records at the other had nonmatching dosage information, probably reflecting dosage changes noted on the medical record but not reflected on pharmacy records.
CONCLUSIONS: In the sites studied, dispensed prescription records reasonably reflect chart drug entries for drug name, but not necessarily dosage.