Characteristics and Consequences of Drug Allergy Alert Overrides in a Computerized Physician Order Entry System

Design: Chart review was performed on a stratified random subset of all allergy alerts occurring during a 3-month period (August through October 2002) at a large academic hospital. Measurements: Factors that were measured were drug/allergy combinations that triggered alerts, frequency of specific override reasons, characteristics of ADEs, and completeness of allergy documentation. Results: A total of 6,182 (80%) of 7,761 alerts were overridden in 1,150 patients. In this sample, only 10% of alerts were triggered by an exact match between the drug ordered and allergy listed. Physicians’ most common reasons for overriding alerts were ‘‘Aware/Will monitor’’ (55%), ‘‘Patient does not have this allergy/tolerates’’ (33%), and ‘‘Patient taking already’’ (10%). In a stratified random subset of 320 patients (28% of 1,150) on chart review, 19 (6%) experienced ADEs attributed to the overridden drug; of these, 9 (47%) were serious. None of the ADEs was considered preventable, because the overrides were deemed clinically justifiable. The degree of completeness of patients’ allergy lists was highly variable and generally low in both paper charts and the CPOE system. Conclusion: Overrides of drug-allergy alerts were common and about 1 in 20 resulted in ADEs, but all of the overrides resulting in ADEs appeared clinically justifiable. The high rate of alert overrides was attributable to frequent nonexact match alerts and infrequent updating of allergy lists. Based on these findings, we have made specific recommendations for increasing the specificity of alerting and thereby improving the clinical utility of the drug allergy alerting system. j J Am Med Inform Assoc. 2004;11:482–491. DOI 10.1197/jamia.M1556. Computerized physician order entry (CPOE) has gained recognition as a key tool that health care organizations can implement to improve patient safety. Increasing evidence shows that CPOE can reduce the frequency of medication errors in the inpatient setting. Many of the beneficial effects of CPOE result from integrated decision support tools, including suggestions regarding appropriate drug dosing, and real-time alerting for drug–drug interactions and drug allergies. Drug allergy alerting represents a particularly important part of decision support. Even though only about 20% of patients react when they receive medications to which they have ‘‘known allergies,’’ the reactions can be devastating when they occur. It should be possible to develop tools to warn providers reliably when the patient has had a prior reaction to a medication, whether an allergy (immune-mediated type I hypersensitivity reaction), or a sensitivity (adverse drug reaction that is non–immune-mediated, e.g., nausea or diarrhea). In CPOE applications that maintain patients’ medication and allergy lists, ordered drugs can be checked Affiliations of the authors: Division of General Internal Medicine, Brigham and Women’s Hospital, Boston, MA (TCH, PH-D, JF, DHW, DWB, TKG); Department of Clinical Practice Evaluation, New YorkPresbyterian Hospital, New York, NY (GJK); The Advisory Board Company, Washington, DC (TJ). Supported by a grant from the National Library of Medicine (R01 LM007203) and a student research grant from Harvard Medical School. The authors thank Cathy A. Foskett, RN, and Katherine R. Zigmont, RN, for their assistance with chart review and data collection; Elisabeth Burdick, MS, and Brian Chan, BS, for their assistance with the statistical analysis; and Ashish K. Jha, MD, Thomas D. Sequist, MD, Edward Lowenstein, MD, Michael T. Bailin, MD, and Maura E. LeBaron for their support and thoughtful review of the manuscript. Correspondence and reprints: Tejal K. Gandhi, MD, MPH, Division of General Medicine, Brigham and Women’s Hospital, 1620 Tremont Street, 3rd Floor, Boston, MA 02120; e-mail: . Received for publication: 02/09/04; accepted for publication: 07/14/04. 482 HSIEH ET AL., Drug Allergy Alert Overrides