• Patient Safety Primer
  • Last Updated: December 2014

Computerized Provider Order Entry


Several steps must take place before a hospitalized patient receives a medication ordered by a clinician:

  • Ordering: the clinician must select the appropriate medication and the dose and frequency at which it is to be administered
  • Transcribing: the clerk must read the order correctly and communicate it accurately to the pharmacist
  • Dispensing: the pharmacist must check for drug–drug interactions and allergies, then release the appropriate quantity of the medication in the correct form
  • Administration: the nurse must receive the medication and supply it to the correct patient

A classic study of inpatient medication errors found that approximately 90% occurred at either the ordering or transcribing stage. These errors can be due to a variety of causes, including poor handwriting, ambiguous abbreviations, or simple lack of knowledge on the part of the ordering clinician.

Computerized provider order entry (CPOE) refers to any system in which clinicians directly enter medication orders (and, increasingly, tests and procedures) into a computer system, which then transmits the order directly to the pharmacy. These systems have become increasingly common in the inpatient setting as a strategy to reduce medication errors. A CPOE system, at a minimum, ensures standardized, legible, and complete orders and thus has the potential to greatly reduce errors at the ordering and transcribing stages.

CPOE systems are generally paired with some type of Clinical Decision Support System (CDSS). A typical CDSS suggests default values for drug doses, routes of administration, or frequency and may offer more sophisticated drug safety features such as checking for drug allergies or drug–drug or even drug–laboratory (eg, warning a clinician before ordering a nephrotoxic medication in a patient with elevated creatinine) interactions. At the highest level of sophistication, CDSS prevents not only errors of commission (eg, ordering a drug in excessive doses or in the setting of a serious allergy), but also of omission. (For example, an alert may appear such as, "You have ordered vancomycin; would you like to order serum vancomycin level after the third dose?" or, even more sophisticated: "The admitting diagnosis is hip fracture; would you like to order enoxaparin for DVT prophylaxis?")

Prescribers override more than half (53%) of CPOE generated alerts of critical drug-drug interactions (DDIs) without providing a reason. Of the 47% of alerts that were dismissed with clinical justification, 20% were rated as useful to pharmacists and 80% were rated as not useful.

Source: Grizzle AJ, Mahmood MH, Ko Y, et al. Reasons provided by prescribers when overriding drug-drug interaction alerts. Am J Manag Care. 2007;13:573-578. [go to PubMed]

Evidence of Effectiveness

In theory, CPOE offers numerous advantages over traditional paper-based order-writing systems. Examples of these advantages include averting problems with handwriting, similar drug names, drug interactions, and specification errors; integration with electronic medical records, decision support systems, and adverse drug event reporting systems; faster transmission to the pharmacy; and potential economic savings.

These proposed benefits have been empirically confirmed to some extent, and recent studies have added to the evidence base supporting CPOE. CPOE appears to be quite effective at preventing prescribing errors. A meta-analysis found that the likelihood of a prescribing error was reduced by 48% when using CPOE compared with paper-based orders, which translates into more than 17 million medication errors prevented yearly in the United States. However, the effect of CPOE on clinical adverse drug event rates is less clear. Other reviews found that CPOE did not reliably prevent patient harm, and high rates of adverse drug events persist in some hospitals with entirely computerized order entry systems. One interpretation of these results is that decision support is the key intervention in reducing errors, and that CPOE by itself may prevent only clinically inconsequential errors. Also, a significant proportion of medication errors occurs at the dispensing and administration stages, and these errors will not be prevented by CPOE (here, promising error reduction strategies include the involvement of unit-based pharmacists and the use of barcode medication administration systems).

Implementation Issues

Early implementation of CPOE was associated with unexpected adverse consequences in some instances, which may have been attributable to workflow disruptions such as inability to obtain medications quickly in emergencies. Subsequent studies have characterized a variety of unintended consequences of CPOE (Table). These factors contributed to the high-profile failure of an expensive CPOE system. However, as institutions gain experience with CPOE implementation, greater awareness of the potential unintended consequences of this technology may help avoid these problems. Careful planning of the implementation process to minimize workflow disruptions and maximize the system's ease of use has been shown to avert adverse events relating to the new technology.

The integration of CDSS into CPOE systems also requires careful planning, and as yet, many aspects of optimal CDSS integration remain undefined. Decision support alerts can prevent harmful drug–drug interactions and promote use of evidence-based tests and treatments, but excessive and nonspecific warnings can lead to "alert fatigue"—whereby users ignore even critical warnings. Alert fatigue may in part explain why CDSSs appear to result in only modest improvements in adherence to recommended care. Although forcing functions can be used in CDSS to essentially prevent high-risk situations such as co-prescribing drugs with dangerous interactions, this approach can also have unintended consequences. Recent commentaries have called for CPOE and CDSS designers to tailor alerts to maximize safety while avoiding alert fatigue.

Table. Types of Unintended Consequences of Computerized Provider Order Entry Systems

More or new work for clinicians

Unfavorable workflow issues

Never-ending system demands

Problems related to persistence of paper orders

Unfavorable changes in communication patterns and practices

Negative feelings toward the new technology

Generation of new types of errors

Unexpected changes in an institution's power structure, organizational culture, or professional roles

Overdependence on the technology

(Reprinted with permission from Elsevier. In: Campbell EM, Sittig DF, Ash JS, Guappone KP, Dykstra RH. Types of unintended consequences related to computerized provider order entry. J Am Med Inform Assoc. 2006;13:547-556.)

These factors contributed to the high-profile failure of an expensive computerized order entry system. However, as institutions gain experience with CPOE implementation, greater awareness of the potential unintended consequences of this technology will likely avoid these problems. For example, a subsequent study documented successful implementation of the same CPOE system that had been associated with increased pediatric ICU mortality. The authors of the second study carefully planned the implementation process, in collaboration with the early system users, to minimize workflow disruptions and maximize the system's ease of use.

Current Context

Although initial adoption of CPOE was relatively slow, most hospitals and clinics are either implementing or planning to implement some form of CPOE in the near future. A major stimulus for this effort was the federal HITECH Act of 2009. The HITECH Act provided incentives for health care organizations to implement CPOE systems that meet "meaningful use" criteria (which include use of some form of CDSS) by 2015. In addition, CPOE is recommended by the National Quality Forum as one of the 30 "Safe Practices for Better Healthcare." The Leapfrog Group also suggested CPOE implementation as one of its first three recommended "leaps" for improving patient safety.

Back to Top