Weingart SN et al. 2003 "Physicians' decisions to override computerized drug alerts in primary care."

Weingart SN, Toth M, Sands DZ, et al. Physicians' decisions to override computerized drug alerts in primary care. Arch Intern Med 2003;163(21):2625-2631.
"Background: Although computerized physician order entry reduces medication errors among inpatients, little is known about the use of this system in primary care. Methods: We calculated the override rate among 3481 consecutive alerts generated at 5 adult primary care practices that use a common computerized physician order entry system for prescription writing. For detailed review, we selected a random sample of 67 alerts in which physicians did not prescribe an alerted medication and 122 alerts that resulted in a written prescription. We identified factors associated with the physicians' decisions to override a medication alert, and determined whether an adverse drug event (ADE) occurred. Results: Physicians overrode 91.2% of drug allergy and 89.4% of high-severity drug interaction alerts. In the multivariable analysis using the medical chart review sample (n=189), physicians were less likely to prescribe an alerted medication if the prescriber was a house officer (odds ratio [OR], 0.26; 95% confidence interval [CI], 0.08-0.84) and if the patient had many drug allergies (OR, 0.70; 95% CI, 0.53-0.93). They were more likely to override alerts for renewals compared with new prescriptions (OR, 17.74; 95% CI, 5.60-56.18). We found no ADEs in cases where physicians observed the alert and 3 ADEs among patients with alert overrides, a non-significant difference (P=.55). Physician reviewers judged that 36.5% of the alerts were inappropriate. Conclusions: Few physicians changed their prescription in response to a drug allergy or interaction alert, and there were few ADEs, suggesting that the threshold for alerting was set too low. Computerized physician order entry systems should suppress alerts for renewals of medication combinations that patients currently tolerate."
"To assess the potential benefits of computerized prescribing among ambulatory patients by examining the behavior of general internists with respect to high-severity drug interaction and drug allergy alerts generated by a CPOE system used at adult primary care practices."
Type Clinic
Primary care
Small, medium and large
Other Information
Two of the study sites were hospital-based clinics together employing 35 full- and part-time academic internists and 158 medical house officers. Three sites were community-based practices employing a total of 19 full-time internists.
Type of Health IT
Computerized clinical reminders (CRs) and alerts
Type of Health IT Functions
The CPOE system includes "drug interaction and drug allergy checks for all prescription orders. Allergy alerts were generated by linking a central database that includes information about each patient's drug allergies and intolerances that was entered by nurses, physicians, and pharmacists in the inpatient, ambulatory, and home care settings. The allergy program triggers an alert if the prescription matches the brand or generic name of the drug or allergen group defined by the National Drug Data File of First Databank, Inc, San Bruno, Calif. Drug interaction alerts were generated by checking patients' electronic medication list using rules in the National Drug Data File of First Databank. First Databank identifies 3 drug interaction severity levels. Level 1 alerts indicate the potential for serious or life-threatening injury and are based on substantial empirical evidence. Level 2 alerts indicate the potential for less serious injury. Level 3 alerts, like level 1 alerts, indicate the potential for serious or life-threatening injury, but the evidence of the interaction is less compelling. A single prescription could generate a drug allergy alert and multiple drug interaction alerts. When an alert is generated, a note appears on the computer screen that identifies the alerted drug, the drug interaction or allergy, and an indication of the severity of drug interactions (level 1 indicates high; level 2, medium; and level 3, low)... The system also allows the provider to see a detailed, referenced monograph about the alert. To escape from the alert, the prescriber must select deliberately the override menu option; the default is to terminate the order."
Context or other IT in place
The electronic health record (EHR) application included note writing capability; access to lab and path reports; reminders for routine screening and preventative health; and electronic prescribing.
Workflow-Related Findings
"Reviewers agreed with the prescribers' decisions in 185 (97.9%) of 189 cases, including 65 (95.6%) of 68 cases where the physician chose to override a valid alert..." "Reviewers indicated most often that the patient was no longer taking the medication, the interaction was not clinically significant, the patient tolerated the drug(s), and the benefits of treatment outweighed the disadvantages."
"Primary care physicians overrode 91.2% of 352 drug allergy alerts, 89.4% of 574 level 1 drug interaction alerts, 96.3% of 2432 level 2 alerts, and 85.4% of 123 level 3 alerts."
"Physicians overrode the analgesic allergy alert in 13 of 14 cases. In each case, the alert was triggered when a physician wrote a prescription for a drug that was in the same class as the drug to which the patient had an allergy."
"Physicians overrode only 7 of 17 antibiotic allergy alerts. Prescriptions for amoxicillin and a combination of amoxicillin and clavulanate potassium triggered 6 penicillin allergy alerts; all but one was honored. In contrast, physicians overrode all 3 erythromycin allergy alerts triggered by prescriptions for azithromycin (all involved erythromycin intolerance rather than a true allergy)."
"Overall, physicians overrode 31 of 46 drug allergy alerts [and] 91 of 143 drug interaction alerts included in the medical chart review."
"New prescriptions were less often written [after overriding an alert] than renewals (50.0% vs 89.6% among alerted medications; P<.001)."
"In the multivariable logistic regression model, physicians were less likely to prescribe (override) an alerted medication if the patient had multiple medication allergies (odds ratio [OR], 0.70; 95% confidence interval [CI], 0.53-0.93), and if the prescriber was a house officer (compared with a staff physician) (OR, 0.26; 95% CI, 0.08-0.84). Physicians were substantially more likely to override an alert for a renewal of a current prescription than for a new prescription (OR, 17.74; 95% CI, 5.60-56.18)."
"Reviewers judged that 69 (36.5%) of 189 alerts were invalid (including 58 [40.6%] of 143 drug interaction and 11 [23.9%] of 46 drug allergy alerts)."
Study Design
Only postintervention (no control group)
Study Participants
A total of 212 primary care physicians (internists and medical house officers) were employed at the five sites that participated in the study.