Medication cost information in a computer-based patient record system. Impact on prescribing in a family medicine clinical practice.

BACKGROUND: Medications account for 8% of national health care expenditures, and prescription drugs are a focus of cost containment measures. Physicians have limited knowledge about drug costs, and no method of providing this information has demonstrated sustained cost reductions.

OBJECTIVE: To determine the impact of cost information in a computer-based patient record system on prescribing by family physicians.

METHODS: A yearlong, controlled clinical trial was conducted at the Family Medicine Center, Medical University of South Carolina, Charleston, a group practice staffed by attending physicians and residents. Prescription cost information was included in the computer-based patient record system used at the center. During a 6-month period, cost information was not displayed; during the subsequent 6-month intervention period, costs were displayed at the time of prescribing. An intention-to-treat analysis was used to compare prescription costs between the control and intervention periods for all medications prescribed, and stratified analyses for several medication and physician factors were performed.

RESULTS: A total of 22,883 prescriptions were written during the 1-year study period. The mean +/- SD cost per prescription in the control period was $21.83 +/- $27.00 (range, $0.01-$510.00), and in the intervention period was $22.03 +/- $28.12 (range, $0.01-$435.96) (P = .61, Student t test). Increases in mean prescription cost and proportion of total costs were identified in 4 medication classes: antibiotics, cardiovascular agents, headache therapies, and antithrombotic agents. Decreases in mean prescription cost and proportion of total costs were identified in 5 medication classes: nonsteroidal anti-inflammatory drugs, histamine type 2-receptor antagonists and proton pump inhibitors, ophthalmic preparations, vaginal preparations, and otic preparations.

CONCLUSIONS: In this setting, the provision of real-time computerized drug cost information did not affect overall prescription drug costs to patients, although differences in individual medication classes were observed. The negative results of this study may reflect confounding due to the use of historical controls, suboptimal timing of the intervention in the prescribing process, susceptibility bias at the study site, or the insensitivity of prescribing habits to cost information.