Frequency, Timing, and Types of Medication Ordering Errors Made by Residents in the Electronic Medical Records Era

Ari Garber, MD, EdD; Amy S. Nowacki, PhD; Alexander Chaitoff, MPH; Andrei Brateanu, MD; Colleen Y. Colbert, PhD; Seth R. Bauer, PharmD; Zubin Arora, MD; Ali Mehdi, MD; Simon Lam, PharmD; Abby Spencer, MD; Michael B. Rothberg, MD, MPH


South Med J. 2019;112(1):25-31. 

In This Article

Abstract and Introduction


Objectives: To describe associations between resident level of training, timing of medication orders, and the types of inpatient medication ordering errors made by internal medicine residents.

Methods: This study reviewed all inpatient medication orders placed by internal medicine residents at a tertiary care academic medical center from July 2011 to June 2015. Medication order errors were measured by pharmacists' reporting of an error via the electronic medical record during real-time surveillance of orders. Multivariable regression models were constructed to assess associations between resident training level (postgraduate year [PGY]), medication order timing (time of day and month of year), and rates of medication ordering errors.

Results: Of 1,772,462 medication orders placed by 335 residents, 68,545 (3.9%) triggered a pharmacist intervention in the electronic medical record. Overall and for each PGY level, renal dose monitoring/adjustment was the most common order error (40%). Ordering errors were less frequent during the night and transition periods versus daytime (adjusted odds ratio [aOR] 0.93, 95% confidence interval [CI] 0.91–0.96, and aOR 0.93, 95% CI 0.90–0.95, respectively). Errors were more common in July and August compared with other months (aOR 1.05, 95% CI 1.01–1.09). Compared with PGY2 residents, both PGY1 (aOR 1.06, 95% CI 1.03–1.10), and PGY3 residents (aOR 1.07, 95% CI, 1.03–1.10) were more likely to make medication ordering errors. Throughout the course of the academic year, the odds of a medication ordering error decreased by 16% (aOR 0.84, 95% CI 0.80–0.89).

Conclusions: Despite electronic medical records, medication ordering errors by trainees remain common. Additional supervision and resident education regarding medication orders may be necessary.


In 1999, the Institute of Medicine released To Err is Human: Building a Safer Health System, which reported that an estimated 98,000 hospital deaths were associated with medical errors.[1] This was followed by the Institute's Crossing the Quality Chasm: A New Health System for the 21st Century, which proposed rules for redesigning healthcare delivery and targeted injury to patients within healthcare systems as a national priority.[2] Almost 20 years later, however, medical errors are still considered to be a leading cause of death in the United States.[3]

Medication errors are one common form of medical error. Despite reforms, medication errors and adverse drug events are responsible for an estimated 700,000 emergency department visits and 120,000 hospitalizations annually.[4] In the hospital, it is estimated that each patient is exposed to more than one medication error per day[2,4] at a cost of billions of dollars.[5–7]

In academic medical centers, residents place most of the medication orders for their patients, and the majority of medication errors originate in the ordering phase.[8,9] Little is known about the association between resident training level and frequency of medication order errors, or when medication order errors occur. To date, most studies exploring factors associated with resident medication errors have focused on a few variables, including work hour restrictions, physiological state (eg, sleep deprivation from excessive duty hours), and/or resident mental health (eg, depression, burnout).[10–15] The few studies that examined the relation between training level and temporal patterns of medical errors have elucidated the "July effect," suggesting that errors increase in July as new interns begin training; however, these studies often analyzed outcomes in aggregate and did not specifically address medication errors or medication order errors.[16] Finally, the few studies that examined the pattern of resident medication errors by time of day were conducted before the passage of the Health Information Technology for Economic and Clinical Health Act of 2009 and the subsequent widespread adoption of electronic medical record (EMR) platforms.[17–20]

To better understand trends in trainees' medication order errors, we reviewed 4 years of medication ordering data identified in real time at a large academic medical center. Our objective was to describe the types of medication ordering errors that residents made, the training level of residents involved, and the timing of the errors to inform future interventions. We hypothesized that medication order error rates would decrease as residents gained experience and that they would be highest at night, when there is less supervision.