Impact of an evidence-based computerized decision support system on primary care prescription costs.

Purpose: Although newer, heavily promoted medications are commonly prescribed, published evidence and consensus guidelines often support the use of less expensive alternatives. This study was designed to evaluate the impact on prescription costs of a computerized decision support system (CDSS) that provides evidence-based recommendations to clinicians during the electronic prescribing process.

Methods: A retrospective cohort study was performed using a pharmacy claims database. Clinicians using the CDSS were matched with a control group by pharmacy billed amount, number of patients treated, and number of new prescriptions filled during a 6-month baseline period in which neither group used the system. The primary outcome measure was the difference in prescription costs between the 2 groups after implementation of the CDSS in the intervention group.

Results: Clinicians who received evidence-based messages had significantly lower prescription costs than those in the control group. The average cost per new prescription was 4.16 dollars lower (P = .02) in the intervention group, and the average cost for new and refilled prescriptions was 4.99 dollars lower (P = .01). The 6-month savings from new prescriptions and their refills are estimated to be 3,450 dollars (95% CI, 1,030-5,863 dollars) per clinician.

Conclusions: Providing electronic, evidence-based decision support during the prescribing process can shift prescribing decisions toward more evidence-based care and significantly decrease primary care prescription costs.