Unintended Effects of a Computerized Physician Order Entry Nearly Hard-Stop Alert to Prevent a Drug Interaction

Background: The effectiveness of computerized physicianorderentry(CPOE)systemshasbeenmodest,largely because clinicians frequently override electronic alerts. Methods:To evaluate the effectiveness of a nearly “hard stop”CPOEprescribingalertintendedtoreduceconcomitant orders for warfarin and trimethoprim-sulfamethoxazole, a randomized clinical trial was conducted at 2 academicmedicalcentersinPhiladelphia,Pennsylvania.Atotal of 1981 clinicians were assigned to either an intervention groupreceivinganearlyhardstopalertoracontrolgroup receiving the standard practice. The study duration was August 9, 2006, through February 13, 2007. Results:The proportion of desired responses (ie, not reordering the alert-triggering drug within 10 minutes of firing) was 57.2% (111 of 194 hard stop alerts) in the intervention group and 13.5% (20 of 148) in the control group (adjusted odds ratio, 0.12; 95% confidence interval,0.045-0.33).However,thestudywasterminatedearly because of 4 unintended consequences identified among patients in the intervention group: a delay of treatment with trimethoprim-sulfamethoxazole in 2 patients and a delay of treatment with warfarin in another 2 patients. Conclusions: An electronic hard stop alert as part of an inpatient CPOE system seemed to be extremely effective in changing prescribing. However, this intervention precipitated clinically important treatment delays in 4 patients who needed immediate drug therapy. These results illustrate the importance of formal evaluation and monitoring for unintended consequences of programmatic interventions intended to improve prescribing habits. Trial Registration: clinicaltrials.gov Identifier: NCT00870298