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Published on 28 January 2010

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Electronic prescribing: effect on medication errors and adverse drug events


Electronic prescribing can make things faster, but the concern is whether administration will run more smoothly in the long run

University for Health
Sciences, Medical
Informatics & Technology
(UMIT), Tyrol, Austria

Electronic prescribing can play an important role in reducing medication errors and improving patient safety. However, electronic prescribing is only used by a limited number of hospitals, and it can introduce new kinds of errors. The introduction of electronic prescribing is a long, costly and multiprofessional project. Before starting, hospitals should ensure they are sufficiently prepared from a technical, personnel and organisational point of view.

Medication errors and CPOE
Medication errors seem to be quite frequent in healthcare. A report from the Institute of Medicine (IOM) that was published in 1999 stated that annually in the USA some 7,000 deaths can be associated with medication errors.[1] Recent data suggest that an estimated 770,000 people in the USA are injured or die in hospitals from adverse drug events (ADEs).[2] Around a third of these ADEs seem to be preventable, and the majority of preventable ADEs occur during drug ordering.[2]

The IOM report from 1999 was the starting point for a number of reports and initiatives on patient safety, proposing-among nontechnical initiatives” to implement electronic prescribing to reduce the number of medication errors.[3] Not surprisingly, industry also took up this topic and promoted electronic prescribing within computerised physician order entry (CPOE)
systems.[4] CPOE refers to a variety of computer-based systems for ordering medications, which share the common feature of automating the medication ordering process.[5]

CPOE systems can range from systems that only provide a list of possible medications for the physician to choose from, to systems providing varying levels of decision support, including checks of drugs “drug interactions, drug allergy contraindications or prescriptions concerning the patient’s recent laboratory results.

All these checks lead to alerts and reminders given to the ordering physician in case problems are detected. In the USA, only 5% of hospitals have fully implemented CPOE,[6] among them the Veterans Affairs Department with more than 150 hospitals. However, according to the most recent HIMSS survey,[7] half of the CIOs see CPOE as the most important application for the next two years. In Europe, the number of hospitals with CPOE will probably be even lower, despite recent European patient safety initiatives such as mandatory electronic drug documentation and an error reporting system in Denmark (see health-eu/care_for_me/patient_safety for an overview on European activities).

While implementation rates of CPOE systems may grow, there is also an increasing realisation that their deployment is a complex and costly endeavour, where potential benefits may be outweighed by the fact that they may increase workload for the ordering physician and may introduce new errors. Thus, the still low implementation rate may stem more from the organisational challenges than from technical problems.

Now let’s have a look at the available evidence from a scientific point of view.

Impact of electronic prescribing
Electronic prescribing is expected to reduce medication errors and thereby have an impact on ADEs. Over the past decade, more than a dozen scholarly articles have been published in support of the hypothesis that CPOE systems can reduce medical errors. Several systematic reviews have tried to summarise the findings.

A recent meta-analysis performed by our group found 25 studies that analysed the effect of electronic prescribing on medication error rate.[8] Twenty-three of those studies showed a significant relative risk reduction of 13-99% for medication errors by electronic prescribing. But we found only six studies that analysed the effect of electronic prescribing on ADEs, and only four of them showed a significant relative risk reduction
for ADEs of 30-84%.

From a clinical perspective, the observed effect sizes (up to 99% reduction of medication errors, up to 84% reduction of ADEs) seem to be rather large. However, the medication errors and ADEs are just surrogate outcomes, and are not necessarily directly related to changes in the patient-relevant medical outcomes.

The actual improvements in medical outcomes (eg, reduction in mortality rates or hospitalisation days) have not yet been sufficiently analysed by quantitative, controlled trials. One exception is the study by Han et al,[9] which observed an increase in mortality after the introduction of a CPOE system. But the Han study was heavily discussed due to methodological weaknesses, and its findings could not be reproduced later on by other researchers.

Altogether, there seems to be sufficient evidence that electronic prescribing can reduce medication errors. Whether this has a significant impact on ADEs and on clinical outcome has still to be investigated. Please also note that the majority of studies are conducted in the USA and in university settings, often focusing on homegrown, self-developed systems. Therefore, evidence for other types of hospitals, for other countries and especially for commercial systems is still weak.

Potential negative effects of electronic prescribing
Recently, after some reports on problems and failures of electronic prescribing projects (a famous one being the Cedars-Sinai case ” see html), researchers became increasingly interested in the unexpected and negative outcomes of electronic prescribing. For example, one study[10] found that CPOE may:

  • Lead to additional workload for physicians, forcing them to enter systematically required information, respond to alerts, and so on.
  • Interrupt communication flows, “meaning that people think that just because the information went into the computer the right person will see it and act on it appropriately.”
  • Disturb established clinical workflow, affecting organisational structures, where “autonomy of physicians is reduced, while the power of the nursing staff, information technology specialists, and administration is increased.”
  • Even lead to new kind of errors such as “juxtaposition errors, in which clinicians click on the adjacent patient name or medication from a list and inadvertently enter the wrong order.”

In summary, there is increasing evidence that electronic prescribing may lead in fact to new errors and consequently to a reduction in patient safety in some aspects.

Practice and policy issues
Given the potential benefit of electronic prescribing, combined with the potential danger of such systems, we should be careful not to follow the rising pressure from the CPOE industry and other CPOE promoters who promise that CPOE is a “golden bullet” to solve all problems of patient safety. Instead, hospitals considering implementing electronic prescribing should be
aware that:

  • Quite some funding needs to be available for purchase and customisation, introduction and teaching, and operation.
  • Introduction of electronic prescribing will heavily influence the established organisational and communication processes.
  • User involvement and project management is at least as important as technical questions.
  • Electronic prescribing must be firmly integrated into an available clinical information system, to avoid double data entry and inconsistent data.
  • Electronic prescribing may introduce new kinds of errors; this has to be closely monitored.
  • Electronic prescribing is only one aspect of drug safety; other parts of the medication cycle may need support, too, such as by automatic dispensing machines.

Electronic prescribing can play an important role in reducing medication errors and improving patient safety. However, scientific evidence on its benefits on ADEs and clinical outcomes from settings outside the USA and other than university hospitals is still not very strong.

Besides, CPOE can introduce new problems. Before starting out on such a system, hospitals should make sure they are fully prepared from a technical, personnel and organisational point of view.

1. Kohn L, Corrigan J, et al. National Academy Press; 2000.
2. Kaushal R, Shojania KG, et al. Arch Intern Med 2003;163(12):1409-16.
3. Smith J. Department of Health; 2004.
4. The Leapfrog Group. 2006; Available from:
5. AHRQ. Making health care safer- a critical analysis of patient safety practices. Chapter 6: computerized physician order entry (CPOE) with clinical decision support systems (CDSSs).
Evidence Report/ Technology Assessment, No. 43. Agency for Healthcare Research and Quality. http://www.ahrq. gov/clinic/ptsafety.
6. Cutler DM, Feldman NE, et al. Health Aff (Millwood) 2005;24(6):1654-63.
7. HIMSS. The 18th Annual HIMSS Leadership Survey-CIO Results Final Report. 2007. Available from: http://www.himss. org/2007survey/DOCS/ ualLeadershipSurvey.pdf
8. Ammenwerth E, Schnell-Inderst P et al. J Am Med Inform Assoc 2008;15(5):585-600.
9. Han YY, Carcillo JA, et al. Pediatrics 2005;116(6):1506-12.
10. Ash JS, Sittig DF, et al. J Am Med Inform Assoc 2007;14(4):415-23.

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