Although prescribing errors are one of the most common causes of preventable iatrogenic injury, there have been relatively few studies of their incidence and causes. The majority of the studies that have been carried out have been based in secondary care. This paper reviews what is currently known about prescribing errors. It is suggested that prescribing errors occur in at least 1-2% of all medication orders written, cause harm in about 1% of admissions, and have a wide range of causes. Organisation-wide interventions and cultural changes are likely to be required to prevent them. However, useful first steps suggested include reporting prescribing errors identified, formally reviewing pharmacists’ interventions and developing increased ‘error awareness’ amongst all health care professionals.peer-reviewe

Dean, Bryony

English

OAR@UM

12          thechronic✱ill     No 5 Summer 2001Prescribing ErrorsWhat’s the Story?Bryony Dean B. Pharm MSc PhD MRPharmsPrincipal Pharmacist Clinical Services and Director, Academic Pharmacy UnitPharmacy Department, Hammersmith Hospitals NHS Trustemail: bdean@hhnt.orgKeywords: prescribing errors, medication errors, adverse drug eventsAlthough prescribing errors are one of the most commoncauses of preventable iatrogenic injury, there have beenrelatively few studies of their incidence and causes.  Themajority of the studies that have been carried out have beenbased in secondary care.  This paper reviews what is currentlyknown about prescribing errors. It is suggested thatprescribing errors occur in at least 1-2% of all medicationorders written, cause harm in about 1% of admissions, andhave a wide range of causes.  Organisation-wide interventionsand cultural changes are likely to be required to prevent them.However, useful first steps suggested include reportingprescribing errors identified, formally reviewing pharmacists’interventions and developing increased ‘error awareness’amongst all health care professionals.IntroductionMedical errors and the harm they cancause are receiving increasing attention.In the UK, the Department of Healthrecently issued two reports highlightingthis problem1,2 and an entire issue of theBritish Medical Journal has beendevoted to the subject3.  In the US, theInstitute of Medicine report ‘To err ishuman: building a safer health system’4has received worldwide publicity.  It isclear that medical errors are causingconcern amongst patients, health careprofessionals and governments alike.Medication errors are one of themost common types of medical error5.It has been estimated that 1-2% ofpatients admitted to US hospitals areharmed as a result of medicationerrors6, and that each error that resultsin harm costs an additional US$5000excluding legal costs7.  In the UK, ithas been recommended that seriouserrors in the use of prescribed drugsshould be reduced by 40% by 20051.  Ina landmark US study, the majority ofthe preventable adverse drug events(mediation errors that result in harm)were specifically attributed toprescribing, rather than dispensing oradministration8,9.  It is thereforesurprising that there have been fewstudies of prescribing errors and theircauses.  This paper reviews what we doknow about prescribing errors andsuggests some ways forward.  It isbased on a literature search carried outusing Medline and Embase databases toidentify studies of prescribing errorspublished between 1980 and April2001. Studies of standards ofprescription-writing, rather thanprescribing errors, are excluded.Studying prescribing errorsA word of caution - the prescribingerror literature can be difficult tointerpret!  The results of many studiesdo not distinguish between thedifferent types of medication error suchas prescribing, dispensing andadministration errors5,10-12.  Others donot differentiate between medicationerrors and adverse drug reactions13-15.There are also wide differences in thedefinitions and data collection methodsused6, although a standard practitioner-led definition has now beendeveloped16.How often do prescribingerrors occur?Studies of the prescribing errorfrequency generally fall into twogroups, those based on pharmacistreview of medication orders and thosebased on the identification of patientharm.  Each of these will be consideredin turn.  Most research into prescribingerrors has taken place in US hospitals,although more recently studies havealso taken place elsewhere.Pharmacists’ Reviewof Medication OrdersIn the US, pharmacists reviewingmedication orders in the course of theirprescription monitoring duties haveidentified (and prevented) prescribingerrors in 0.3 to 1.9% of all medicationorders written17-20.  However, carefulexamination of these studies revealssome variation in the definitions of anerror used and comparisons amongstthem should be made with caution.The most prolific authors in thisarea are Lesar and colleagues, based ina teaching hospital in New York State.In their first study, an error wasidentified in 0.3% of all medicationorders written17. The most commoncategory of error was ‘wrong dose’errors.  When ‘problem orders’ (errorswithout toxic potential, errorsNo 5 Summer 2001    thechronic✱ill         13concerning doses that were unlikely tobe given, and missing information)were excluded, the ‘significant’ errorrate was 0.2%.  As a result of thesefindings, an ongoing prescribing errormonitoring programme was initiated.  Atotal of nine years’ data were laterpublished21, which suggested that therate of significant errors had increasedfrom 0.2% to 0.4%.  However, as theauthors point out, these error rates arelikely to be an underestimate of thetrue error rate, as many errors will goundetected by dispensary-basedpharmacists.In a further study, the same authorsexamined a series of significant errorsto explore the most likely contributingfactors18. The contributory factors wereassigned by the investigators ratherthan the prescribers involved.Nevertheless, the results suggest thatthe most common factors involvedknowledge about drugs and knowledgeabout patient characteristics that affectdrug handling.  Analyses of data forspecific groups of drugs suchas antimicrobials have also beenpublished22.There have been far fewer studiesoutside of the US.  Twenty-five yearsago, Tesh and Beeley23 carried out aretrospective review of 455 patients’drug charts in a UK hospital.  Theseinvestigators examined errors in druguse and errors in prescription writingsuch as prescribing by brand name.  Itwas concluded that more than 30% ofall medication orders contained an errorof prescription writing.  The medicalnotes were also reviewed for 385patients to identify any contra-indications to the drugs prescribed; itwas concluded that overall, 3.6% of allmedication orders were associated withan error in drug use.More recent UK studies have focusedon pharmacists’ clinical interventions.For example, Hawkey et al.24 recordedinterventions in six hospitals.  It wasfound that pharmacists madeinterventions in about 2.9% of allprescriptions, and that the majorityconcerned drug doses.  In the formerNorth Thames Region of England,hospital pharmacists record allinterventions made during one weekeach year.  These data are then collatedand analysed centrally.  For example,Barber et al.25 reported that 3501interventions were made for 10,478occupied beds during a one-weekperiod, equivalent to 33 interventionsper 100 beds per week.  However, suchstudies do not allow firm conclusions tobe drawn regarding the frequency ofprescribing errors, as pharmacists’interventions also include advice-giving, formulary issues and patientcounselling.In a more recent UK study,pharmacists recorded details of allprescribing errors identified in non-obstetric inpatients during a four-weekperiod26.  The number of medicationorders written was estimated from a 1in 5 sample of inpatients.  An error wasidentified in 1.5% of all prescriptionswritten, of which one quarter werejudged to be potentially serious.  As inother studies, the majority (59%) wereassociated with choice of dose.In studies of this type, the errorsreported are those that pharmacistsidentify and draw to the prescribers’attention.  The medication ordersconcerned are usually corrected beforethe patient receives the medication.There are therefore no adverse patientoutcomes.  In contrast, studies basedon the identification of harm includeonly the subset of errors that reach thepatient and result in injury.Identification of harmSuch studies usually includeiatrogenic injury of many differentkinds, but depending on how the dataare presented, the frequency ofmedication-related events can usuallybe identified.  The US Harvard study5 isprobably the most well known study ofiatrogenic harm and was based on theretrospective review of more than30,000 medical records.  This studysuggested that a medication errorcaused harm in 0.7% of inpatients.  Asimilar study in Australia identified afigure of 1.8%27.  However, thesefigures include both prescribing andadministration errors and the results donot allow differentiation between them.The Adverse Drug Event (ADE)Prevention Study Group examinedmedication-related harm in moredetail8.  This six-month study includedall adults admitted to a stratifiedsample of wards in two large hospitals.A medication error that resulted inharm (‘preventable ADE’, in the authors’terminology) was identified in 1.8% ofadmissions.  Prescribing accounted forthe majority of these, representing1.0% of all admissions.  The staffinvolved were also interviewed toobtain details of the circumstancessurrounding each error9.  As in Lesar etal’s study18, the most common causeswere lack of knowledge about the drugand lack of knowledge about thepatient.  More recently, a similar studywas carried out in two paediatrichospitals; a preventable ADE wasidentified in 0.4% of admissions28.Why do prescribing errorsoccur? Surprisingly, there has been littleresearch into the reasons whyprescribing errors occur.  While manyhealth care professionals have theirown hypotheses about the causes ofprescribing errors, there is littleevidence on which to base thesetheories.  There is, however, a growingbody of research concerning humanerror in other fields.Theories of human error have beenused for some time to analyse errors inhigh-risk environments such as aviationand nuclear power, and have morerecently been applied to medicine29,30.There are many different approaches tothe study of human error31, butReason’s accident causation model32 isthe most widely used.  This model isbased on the assumption that ‘activefailures’ on the part of front-lineindividuals are largely the result of theconditions in which they work, oftentermed ‘error producing conditions’.These in turn are the result of fallibledecisions at an organisational level,known as ‘latent conditions’.  There istherefore less focus on the individualwho makes the error and more on pre-existing organisational factors. Theadvantage of using this approach isthat it aids the identification ofrelevant latent conditions, the primaryfocus of intervention33.  Reason’s modelhas now been used to investigate andanalyse incidents in obstetrics34, mentalhealth35 and other clinical settings29.  Ithas also been used to develop aprotocol for the routine investigation ofadverse incidents in hospitals36.14          thechronic✱ill     No 5 Summer 2001References1. Expert Group on Learning from Adverse Eventsin the NHS. An organisation with a memory.London. Department of Health; 2000.2. Department of Health. Building a safer NHS forpatients. London. Department of Health; 2001.3. Leape LL, Berwick DM. Safe health care: are weup to it? British Medical Journal2000;320:725-6.4. Kohn L, Corrigan J, and Donaldson M [editors].To err is human: building a safer healthsystem.  Report of the Committee on Quality ofHealth Care in America, Institute of Medicine.Washington: National Academy Press; 2000.5. Leape LL, Brennan T, A., Laird N et al.  Thenature of adverse events in hospitalizedpatients.  Results of the Harvard medicalpractice study II. New England Journal ofMedicine 1991;324:377-84.6. Barber ND, Dean BS. The incidence ofmedication errors and ways to reduce them.Clinical Risk 1998;4:103-6.7. Bates DW, Spell N, Cullen DJ et al. The costs ofadverse drug events in hospitalized patients.JAMA 1997;277:307-11.8. Bates DW, Cullen DJ, Laird N et al. Incidence ofadverse drug events and potential adverse drugevents:Implications for prevention. JAMA1995;274:29-34.9. Leape LL, Bates DW, Cullen DJ et al. Systemsanalysis of adverse drug events. JAMA1995;274:35-43.10. Jozefczyk KG, Schneider PJ, Pathak DS.Calculating medication error rates - reply.American Journal of Hospital Pharmacy1987;44:104611. Andrews LB, Stocking C, Krizek T et al. Analternative strategy for studying adverse eventsin medical care. Lancet 1997;349:309-13.12. Brennan TA, Leape LL, Laird N et al. Incidenceof adverse events and negligence inhospitalised patients. New England Journal ofMedicine 1991;324:370-6.13. Classen DC, Pestotnik SL, Burke JP.Computerized surveillance of adverse drugevents in hospital patients. JAMA1991;266:2847-51.14. Classen DC, Pestotnik SL, Evans RS, Lloyd JF,Burke JP. Adverse drug events in hospitalizedpatients.  Excess length of stay, extra costs andattributable mortality. JAMA 1997;277:301-6.15. Schneider PJ, Gift MG, Lee YP et al. Cost ofmedication-related problems at a universityhospital. American Journal of Health-SystemPharmacy 1995;52:2415-8.16. Dean B, Barber N, Schachter M. What is aprescribing error? Quality in Health Care2000;9:232-7.17. Lesar TS, Briceland LL, Delcoure K et al.Medication prescribing errors in a teachinghospital. JAMA 1990;263:2329-34.18. Lesar TS, Briceland L, Stein DS. Factors relatedto errors in medication prescribing. JAMA1997;277:312-7.19. Blum KV, Abel SR, Urbanski CJ, Pierce JM.Medication error prevention by pharmacists.American Journal of Hospital Pharmacy1988;45:1902-3.20. Folli HL, Poole RL, Benitz WE, Russo JC.Medication error prevention by clinicalpharmacists in two children’s hospitals.Pediatrics 1987;79:718-22.21. Lesar TS, Lomaestro BM, Pohl H. Medication-prescribing errors in a teaching hospital. ArchIntern Med 1997;157:1569-76.22. Briceland LL, Lesar TS, Fausel CA etal.Antimicrobial prescribing errors averted bypharmacists: Why do errors occur? Journal ofInfectious Diseases Pharmacology 1999;3(4):1-17.23. Tesh DE, Beeley L, Clewett AJ et al. Errors ofdrug prescribing. British Journal of  ClinicalPharmacology 1975;2:403-9.24. Hawkey CJ, Hodgson S, Norman A et al. Effectof reactive pharmacy intervention on quality ofhospital prescribing. British Medical Journal1990;300:986-90.25. Barber ND, Batty R, Ridout DA. Predicting therate of physician-accepted interventions byhospital pharmacists in the United Kingdom.American Journal of Health-System Pharmacy1997;54:397-405.26. Dean B, Barber N, Schachter M et al.Prescribing errors in hospital inpatients.Abstract presented at the 11th InternationalSocial Pharmacy Workshop, Kuopio, 13th - 17thJune 2000.27. Wilson RM, Runciman WB, Gibberd RW et al. TheQuality in Australian Health Care Study. TheMedical Journal of Australia 1995;163:458-71.28. Kaushal R, Bates DW, Landrigan C et al.Medication errors and adverse drug events inpediatric inpatients. JAMA 2001;285: 2114-20.29. Vincent C, Taylor-Adams SE, Stanhope N.Framework for analysing risk and safety inclinical practice. British Medical Journal1998;316:1154-7.30. Helmreich RL. On error management: lessonsfrom aviation. British Medical Journal2000;320:781-5.31. Reason J. Human Error. Cambridge: Universityof Cambridge; 1990.32. Reason J. Human error: models andmanagement. British Medical Journal2000;320:768-70.33. Reason J. Managing the risks of organisationalaccidents. Aldershot: Ashgate; 1997.34. Stanhope N, Vincent C, Taylor-Adams SE et al.Applying human factors methods to clinical riskmanagment in obstetrics. British Journal ofObstetrics and Gynaecology 1997;104:1225-32.35. Vincent C, Stanhope N, Taylor-Adams SE.Developing a systemic method of analysingserious incidents in mental health. Journal ofMental Health 2000;9:89-103.36. Vincent C, Taylor-Adams SE, Chapman EJ et al.How to investigate and analyse clinicalincidents: Clinical Risk Unit and Association ofLitigation and Risk Management Protocol.British Medical Journal 2000;320:777-81.37. Dean B, Barber N, Schachter M et al.Prescribing errors in hospital inpatients: why dothey occur? Pharmaceutical Journal 2000;26However, this approach has onlyrecently been applied to prescribingerrors37.  In this UK study, forty-fourinterviews were conducted withprescribers making potentially seriouserrors.  It was found that active failureswere usually slips in attention ormistakes such as not applying relevantrules.  Doctors identified many error-producing conditions; these includedwork environment, workload, whetheror not they were prescribing for theirown patient, communication withintheir team, physical and mental well-being, and lack of knowledge.  Latentconditions included lack of training,low perceived importance ofprescribing, a hierarchical medicalteam, and a lack of self-awareness oferrors.  It was concluded that amongstother things, we need to create aculture in which prescription writing isseen as important and to sensitisehealth care professionals to situationsin which errors are most likely to occur.ConclusionsThe literature suggests thatprescribing errors are a major source ofiatrogenic injury in hospitals.  Whilelittle is known about the incidence oferrors in primary care, there is noreason to suppose that prescribingerrors are any less frequent.  Carefulstudy of the literature also reveals thatthere is wide variation in thedefinitions of a prescribing error used,and that little is known about theircauses or how they can be prevented.Human error theory has been helpful inthe investigation of adverse incidentsin medicine, and has more recentlybeen applied to prescribing errors.Large-scale studies of interventions toreduce prescribing errors are nowrequired. However, useful first stepssuggested include reporting prescribingerrors identified, formally reviewingpharmacists’ interventions anddeveloping increased ‘error awareness’amongst all health care professionals.Any successful intervention to reduceprescribing errors is likely to require theinvolvement of all health careprofessionals. ✱

A et al. Effect of reactive pharmacy intervention on quality of hospital prescribing.

Applying human factors methods to clinical risk managment in obstetrics.

Developing a systemic method of analysing serious incidents in mental health.

Errors of drug prescribing.

Framework for analysing risk and safety in clinical practice.

How to investigate and analyse clinical incidents: Clinical Risk Unit and Association of Litigation and Risk Management Protocol.

Human error: models and management.

Human Error. Cambridge:

Managing the risks of organisational accidents.

Medication errors and adverse drug events in pediatric inpatients.

On error management: lessons from aviation.

Predicting the rate of physician-accepted interventions by hospital pharmacists in the United Kingdom.

Prescribing errors in hospital inpatients: why do they occur?

Prescribing errors in hospital inpatients.

The Quality in Australian Health Care Study.

Prescribing errors : what’s the story?

https://www.um.edu.mt/library/oar/bitstream/handle/123456789/13310/2001-5-4.pdf?sequence=1&isAllowed=y

Prescribing errors : what’s the story?

Abstract

Similar works

Full text

Available Versions

OAR@UM