Objectives (1) Systematically assemble, analyse and synthesise published evidence on causes of prescribing error in children. (2) Present results to a multidisciplinary group of paediatric prescribing stakeholders to validate findings and establish how causative factors lead to errors in practice.
Design Scoping review using Arksey and O’Malley’s framework, including stakeholder consultation; qualitative evidence synthesis.
Methods We followed the six scoping review stages. (1) Research question—the research question was ‘What is known about causes of prescribing error in children?’ (2) Search strategy—we searched MEDLINE, EMBASE, CINAHL (from inception to February 2018), grey literature and reference lists of included studies. (3) Article selection—all published evidence contributing information on the causes of prescribing error in children was eligible for inclusion. We included review articles as secondary evidence to broaden understanding. (4) Charting data—results were collated in a custom data charting form. (5) Reporting results—we summarised article characteristics, extracted causal evidence and thematically synthesised findings. (6) Stakeholder consultation—results were presented to a multidisciplinary focus group of six prescribing stakeholders to establish validity, relevance and mechanisms by which causes lead to errors in practice.
Results 68 articles were included. We identified six main causes of prescribing errors: children’s fundamental differences led to individualised dosing and calculations; off-licence prescribing; medication formulations; communication with children; and experience working with children. Primary evidence clarifying causes was lacking.
Conclusions Specific factors complicate prescribing for children and increase risk of errors. Primary research is needed to confirm and elaborate these causes of error. In the meantime, this review uses existing evidence to make provisional paediatric-specific recommendations for policy, practice and education.
- qualitative research
- medical education and training
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Strengths and limitations of this study
This study used systematic methods to provide a comprehensive review of causes of prescribing errors in children.
We consulted prescribing stakeholders to add key contextual information on how errors happen in practice.
Risk of overemphasising expert opinion was introduced by the decision to include secondary evidence.
Article selection was made potentially subjective because of the study’s inclusive approach, bringing together all evidence that could contribute information on causes of errors.
Thirteen per cent of prescriptions written for children contain errors.1 These lead to harm, which can be catastrophic,2 and increase costs.3 Recent research has clarified the extent of the problem1 4 5 but the causes of errors are still poorly understood. Research in adults6–8 is of limited value because paediatric prescribing errors are different. Potentially harmful errors are three times more common in children.9 The youngest patients are most affected, which suggests that something specific to children causes errors.9 Dosing errors are by far the leading error type,4 including potentially lethal tenfold dosing errors, to which children are much more susceptible.10
There have been limited attempts to synthesise existing evidence about the causes of prescribing errors in children.11 Authors have discussed how prescribing for children differs. But what we know less about is how and why those differences lead to errors. This information is essential for clinicians and educators trying to improve medication safety in children. This article reports a scoping review that, first, systematically assembled and analysed published evidence about the causes of paediatric prescribing errors and, second, presented the findings to a multidisciplinary group of stakeholders to validate findings and provide details of how causative factors lead to errors.
We chose scoping review methodology12 13 because it ‘identifies key concepts, research gaps, and evidence to inform practice, policymaking and research.’14 Scoping reviews use rigorous and transparent methods to identify and analyse relevant literature15 with the added advantage of including heterogeneous, methodologically diverse evidence, and a stakeholder consultation to validate this evidence. These steps are key to understanding complex topics of this sort. A medical student (OK), an endocrinologist and senior medical education researcher (TD), a paediatric specialty trainee undertaking a PhD in medical education (RLC), a professor of child health (MDS) and an academic pharmacist (MPT) conducted the review. We used the six scoping review stages, as laid out by Arksey and O’Malley,12 to provide a structure for the methods, and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) guidelines.16
Identifying the research question
The review question was ‘What is known about causes of prescribing error in children?’ Since preliminary searching had found little explanatory evidence, we defined ‘causes’ to include contributors, predictors, risk factors and correlates of errors.
Identifying relevant studies
We designed the search strategy to find all articles about factors contributing to errors (table 1),17 combining the concepts ‘prescribing’, ‘error’, ‘cause’ and relevant synonyms, limited to children aged 0–18 years. A specialist librarian reviewed the search syntax and applied it to MEDLINE, EMBASE and CINAHL (MEDLINE search terms are shown in online supplementary file 1). We also searched PubMed for articles not yet indexed for MEDLINE, and Google Scholar and EThOS (British Library thesis database) for grey literature. We hand searched reference lists of all included articles to complement database searching, which may miss heterogeneous evidence.18
Screening and selection procedures
We tabulated search results in Microsoft Excel (Microsoft, Redmond, USA), removed duplicates manually and applied the following inclusion and exclusion criteria (summarised in box 1): prescribing error (according to Ghaleb et al.’s definition of clinically important paediatric prescribing errors,19 using handwritten or electronic prescriptions, by doctors, for children and young people aged 0–18). We included drug choice and communication with patients,20 though most errors were reported in prescription writing.
Eligibility criteria for article selection
All studies contributing information on causes of medication prescribing errors (‘as a result of a prescribing decision or prescription writing process, there is an unintentional significant (1) reduction in the probability of treatment being timely and effective or (2) increase in the risk of harm when compared with generally accepted practice’19) of all types in children aged 0–18.
Handwritten or electronic prescriptions.
Did not specifically address children.
Did not contribute information on causes, risk factors, associations or predictors of error.
Study involving adult patients and not possible to discern causes relating to children specifically.
Study investigating medication errors and not possible to discern causes of prescribing errors specifically.
Related to prescribing errors made by non-medical prescribers.
Related to non-drug prescribing, such as prescribing eyeglasses.
Articles not available in English language.
Full-text article could not be retrieved.
In order to refine and then apply the inclusion and exclusion consistently,13 RLC and OK jointly reviewed 100 results. OK then screened all titles and abstracts and recorded reasons for excluding ineligible articles. RLC and OK discussed articles where decisions were unclear, retrieving full texts if necessary. To validate the accuracy of the selection process, all members of the research team independently reviewed 20 abstracts, reaching the same decision in 19/20 cases. OK and RLC then jointly reviewed abstracts or full texts of all remaining articles.
We included ‘primary evidence’ (empirical research) as well as ‘secondary evidence’ from review articles, whose authors advanced well-reasoned arguments for causes of errors based on referenced evidence, experience or authoritative opinion. We included secondary evidence because it contributed understanding of the topic and our methodology included an extra ‘filter’: a consultation exercise, to validate relevance of findings to practice. As is customary in scoping reviews, we did not exclude articles based on quality or design.15Table 2 allows readers to form opinions on the strength of evidence by linking identified causes of error with types of articles and study methodologies.
Charting the data
Using Microsoft Excel, we created a custom data charting form including study demographics, methodology and error causes. OK charted all study details; RLC read all articles and checked the accuracy of her data extraction.
Collating, summarising and reporting results
We tabulated key information from included studies and quantified their characteristics. We then synthesised research findings thematically.21 First, OK and RLC independently coded causes of error in a subset of 20 articles. By discussing their coding, they developed a thematic framework, which OK applied to the remaining articles. RLC checked the accuracy of coding in all articles. We quantified codes, giving a sense of the relative importance attached to the causes of prescribing error described in literature. We then developed themes, which were agreed by all authors.
We purposefully sampled key prescribing stakeholders from a range of backgrounds to participate in a multidisciplinary focus group. RLC presented the findings of the literature review and asked participants to discuss how, in their experience, these factors led to errors. The focus group protocol is included as online supplementary file 2. RLC recorded the discussion and transcribed it verbatim. We analysed the transcript by coding information within the themes from the literature review and then identifying details of how causes led to errors in practice (‘error mechanisms’). Stakeholder evidence is presented within the main text and in a table. Quotations which support findings in the main text are linked by numbers, for example, (3PP1).
Patient and public involvement
We did not involve patients or families in the conduct of this research.
Included and excluded articles
Figure 1 summarises study selection. From 1735 identified articles, 228 were considered potentially contributory after initial exclusions. A further 185 were excluded after two-person review of abstract or full text, as required; this was mainly because they studied error epidemiology (81 articles) or interventions to prevent errors (48 articles) but did not contribute information on errors’ causes. We identified a further 25 articles through reference list searching (22 articles) and by finding relevant studies opportunistically during searching and article retrieval (three articles). Sixty-eight articles were included in the review (n=68)(table 2).
Of the 68 included articles, 59 (87%) were published since 2000 (table 3). The majority were from North America (35 articles; 51%) or the UK (18 articles; 26%). Forty-four (63%) articles reported primary research; of these, 39 were observational studies in clinical settings. These typically identified errors using drug chart/medical record review (21 studies; 42%) or incident reporting (13 studies; 26%). In 20 of the 44 primary studies (45%), factors associated with errors were supported with statistical analysis. Twenty-four (35%) reported secondary evidence, of which 19 were review articles (table 4).
A consultant paediatrician, two paediatric trainees, a paediatric pharmacist/independent prescriber, an advanced paediatric nurse practitioner/independent prescriber and a nurse educator participated in the stakeholder focus group. Four were female and two were male. Their experience working in paediatrics ranged from 3 to 30 years. Stakeholder evidence is presented within the main text and, with direct quotations, in table 5. Quotations are linked to the main text using participant identifiers, for example, (3PP1).
Causes of errors
As in adults, ‘generic’ factors such as prescriber characteristics, organisational problems, working conditions and interprofessional communication caused errors. Table 2 reports these findings in detail. Most articles, however, focused on causes of errors that were specific to children, resulting in six major themes.
Children’s fundamental differences
Fundamental differences between children and adults (16 references) were: rapidly changing, highly variable size and weight22–29; physiology and metabolism22–24 29–31; pharmacokinetics and pharmacodynamics22 23 25–28 31–36; disease states and prematurity24 32 36 37; development (including puberty) and cognition.23 26 29 31 These differences led to five major causes of errors. Growth and changing size necessitate individualised dosing, typically based on weight, age or body surface area, requiring prescribers to perform calculations (45 references). Differences in drug handling mean that pharmacokinetic-pharmacodynamic research conducted in adults does not apply in children, contributing to the practice of off-licence prescribing (14 references).32 The non-standard nature of off-licence treatments, along with developmental differences such as inability to swallow tablets, leads to use of different medication formulations in children (15 references). Development, too, complicates the process of communication with children (seven references). Taken together, these paediatric-specific causes of error mean that prescribers need specific experience working with children (18 references).
Individualised dosing and calculations
Individualised dosing led to errors by placing a high demand on staff to adjust doses or dosing intervals as children grew (3PP1).26 27 31 36 Prescribers did not make these changes or made them incorrectly. Children of the same age varying widely in size also contributed to errors.26–28 Stakeholders recognised this problem and cited examples of small-for-age children receiving excessive doses, even when guidance was correctly followed (1PP1). Obese children were prescribed doses above the maximum recommended for adults (2PP1).
Miscalculation, misplacement of decimal points or confusion around the ‘mg/kg/day’ dosing equations that are common in paediatrics were a major cause of errors.38 Four studies assessed doctors’ ability to perform calculations in written tests.39–42 Presented with common prescribing scenarios, junior doctors frequently made errors; in one study, for example, seven of 21 prescribers made tenfold dosing errors.40 Research showing that computer-calculated doses were significantly more accurate than those calculated manually provided further evidence of this problem.43 Some authors speculated that a subset of doctors were particularly innumerate39 41 but tests showed that most doctors made calculation errors. Stakeholders supported this conclusion by noting that cognitive slips occurred in even simple calculations and were made more likely by workplace pressures and distractions (5PT1). Potentially lethal tenfold dosing errors arising from misplaced decimal points were an example of this.10 44 Checking could not be relied on to prevent errors. In one study, as few as 51% of doctors stated they always double-checked their calculations.40 Similarly, second checking during administration was not always done (5PT1) and, according to stakeholders, was not always successful when it was.
Weighing children—a prerequisite for many dose calculations—also led to errors. These arose from weights being inaccurately measured, recorded or communicated.45 46 Errors also occurred when doctors wrote prescriptions for children without a weight measurement being available (6PT2).32
There was primary47 and secondary48 evidence that using medications without regulatory approval causes prescribing errors. Proposed mechanisms included: a lack of clear dosing information30 33 49; multiple or unclear reference standards (8PT2)25 36; and ‘trial and error’ dosage strategies.27 In some cases, the lack of a licensed product meant using medicines supplied by specialist manufacturers for specified patients, or prepared extemporaneously (7PP1).37 Using these preparations caused errors when prescribers lacked information or information was inaccurately conveyed, for example, between paediatricians, general practitioners (GP) and community pharmacies.37
Liquid formulations caused errors because prescribers had to convert doses from millilitres to milligrams, or vice versa (10PN1).33 50 A lack of paediatric-specific formulations required prescribers to use products designed for adults.2 22 27 30 33 37 This often led to multiple solution strengths being available,24 51 causing errors when drugs were inappropriately prescribed in millilitres.27 Stakeholders confirmed their experiences of relatively small drug volumes leading to massive overdoses, which often did not arouse suspicion in those administering them (9PP1).
Communication with children
Specific difficulties in communicating with children and their parents led to errors. Sometimes parents would give incomplete, misleading or incorrect information about a child’s medications (14PT1).24 30 Often, they stated doses in millilitres, which required prescribers to find out the strength of the solution and convert the volume to a weight for dosing. Doctors’ inadequate communication of prescribing decisions and doses also caused errors (15PC1).29 For example, a GP prescribed a different solution strength from that used in hospital but, due to unclear communication, parents continued to administer the same volume of solution, leading to overdose.52 Problems could be compounded by children being less able to note and report errors27 33 48; equally, however, their parents could act as an important safeguard. One study found that 8% of 2753 reported errors were noticed by parents before administration.53
Experience working with children
There was conflicting evidence about how experience of working with children affected prescribing errors. A study showed that emergency department (ED) trainees were more likely to make errors,54 but in another, most were made by ED attending paediatricians.55 Two studies of trainees showed no relationship between length of training and the likelihood of error in written tests39 40; however, another found that doctors with no paediatric experience were four times less likely to make errors than senior trainees.42 Errors were most prevalent at the beginning of the academic year54 or when new doctors joined the clinical team.44 Paediatric trainees made significantly fewer errors than doctors in other specialties in both clinical and classroom-based studies,41 43 56 57 perhaps because managing children full-time made prescribers more aware of dosing considerations and paediatric-specific protocols (12PT1).52 53 58
This study used a systematic approach to review and synthesise what is known about the causes of prescribing errors in children. We found that, as in adults, a host of social and contextual factors cause errors, such as busy workplaces, poor communication and individual mistakes.6 59 Yet, as described previously, the process of prescribing for children differs from practice in adults, and these differences are reflected in rates and types of errors. This study shows how these fundamental differences in children—including growth, development, physiology and drug handling—caused additional errors. While publications generally consider these paediatric-specific factors in isolation from one another, a multidisciplinary group of stakeholders agreed that, like in adults,6 60 errors occur when multiple factors collide. Within a single prescription, an inexperienced prescriber might have to establish a child’s correct weight, reconcile conflicting information about an unlicensed product, interpret a complex dosing regimen, calculate an accurate dose and communicate this to parents. Figure 2 shows how these factors inter-relate to increase risk of errors.
Nature of the evidence base
Findings should be interpreted within the limitations of the evidence available. It was not always possible to establish detailed causal relationships from secondary evidence. The primary causal evidence identified was also weak because much of it came from quantitative determinations of error rates, which explored statistical associations between potential causative factors as a secondary objective. The ‘causes’ identified within these studies were often self-evident (being on multiple medications),44 61–63 difficult to interpret (junior residents made more errors than more senior ones)57 or non-modifiable (older prescribers).64 Moreover, several studies were conducted in simulated and classroom settings which, while informative, may not fully reflect the complexity of prescribing within practice. Research in adults has addressed these limitations by asserting that prescribers themselves know most about the causes of errors65 and conducting in-depth qualitative interviews with doctors who have been involved in them. This has shown that, rather than just ‘lack of knowledge’, errors have multiple, complex causes strongly influenced by prescribing contexts.6 This new understanding is starting to impact education and practice in medication safety.66
Most studies were relatively recent, reflecting increasing focus on patient safety. Evidence was constrained, however, because the vast majority of studies were conducted in specialist paediatric settings, even though non-specialists frequently care for children. Almost no evidence referred to general practice settings, despite the fact children make up a significant proportion of GP caseload and have been shown to be at increased risk of error.67 Evidence, too, predominately originated from developed countries, particularly North America or the UK. It is unclear how differences in health systems affect prescribing safety; for example, in North America, paediatricians provide primary care, whereas in the UK GPs generally represent the first point of contact for children. There is little evidence, too, about prescribing error in low/middle-income countries, even though research suggests that patient safety issues are no less common but may differ in causation.68
While the broad themes identified in this review are likely to apply in wide range of settings, these limitations impact the transferability of findings and make its recommendations provisional.
Strengths and limitations
The choice of scoping review methodology enabled us to bring together a heterogeneous body of literature that was not amenable to quantitative forms of synthesis. The fact that we included a stakeholder consultation, often omitted in scoping reviews, helped to triangulate findings and ground them in real-world clinical practice.
Our study also had limitations. Our search was conducted in February 2018; we recognise that other contributory articles may have been published in the intervening period. Moreover, our search may have missed contributory articles in which, for example, the term ‘cause’ or its synonyms were not present. We decided to include articles in which authors deduced the causes of errors from experience as well as ‘fact’ because primary evidence for themes other than individualised dosing and calculations and experience in working with children was insufficient. The heterogeneous nature of this evidence made our selection of articles inescapably subjective. We addressed this by working as a team to refine inclusion and exclusion criteria, and independently screening articles to apply the criteria consistently.
Despite the use of two institutions’ libraries, seven potentially contributory articles could not be retrieved. Based on their abstracts, four were review articles that emphasise paediatric-specific factors similar to those described in this study; the other three were primary articles that presented factors including off-licence use of antidepressants, out-of-hours working and specific drug types as associations with error.
Our decision to include secondary evidence introduced a risk of confirmation bias. First, some review articles made reference to included primary studies, giving them additional weighting. Interestingly, however, primary and secondary articles generally appeared to focus on different causes of errors: primary articles often evaluated specific ‘generic’ associations with errors, while secondary articles emphasised ‘paediatric-specific’ causes’. Table 2 enables readers to see the causes of errors found within particular article types.
Second, review articles may have preferentially cited other secondary literature written by influential authors, giving added weight to their opinions. On this point, it is important to note that qualitative evidence syntheses as used in this study are not suited to testing the strength of associations; the numbers of articles offered alongside individual causes give an indication of the attention a factor has received in literature, rather than its importance in causing errors. Moreover, the stakeholder consultation conducted as part of this review compensated for that risk of bias by inviting experienced practitioners to (dis)confirm the provisional results of the review. This supported the relevance of our tentative conclusions to practice, identified mechanisms and provided real-world examples.
The highly inter-related nature of the causes of errors resonates with research in adults which describes prescribing as a complex process.6 With this in mind, it is clear that solutions on multiple levels will be needed to begin to tackle the problem. Box 2 summarises recommendations to improve paediatric prescribing safety.
Recommendations to improve paediatric prescribing safety
Expand existing research to include all areas of practice, including primary care, and wider geographical representation.
Consider specific unanswered research questions, such as: How can checking processes be improved? How can practitioners with specific mathematical difficulties be supported?
Explore how parents and children can play an increased role in medication safety.
Policy and drug industry level
Standardise medicine concentrations across practice settings.
Promote research to enable paediatric drug licensing.
Support production of paediatric-specific medicine formulations.
Consider the use of age-banded, rather than weight-based, dosing regimens.
Increase the provision of clinical pharmacists.
Introduce paediatric-specific electronic prescribing, electronic health records and clinical decision support tools.
Implement rigorous systems for recording patients’ weights.
Improve mechanisms for practitioners to get support with prescribing, especially for those who do not routinely prescribe for children.
Ensure that all doctors who care for children receive prescribing education.
Provide paediatric prescribing education and opportunities at undergraduate level.
Align educational content with evidence on the specific causes of errors, such as dose calculations and weight-volume conversions.
Consider up-to-date educational strategies such as providing feedback on practice and encouraging reflection.
Research should respond to the complexity of prescribing error by focusing study on their underlying causes to inform design of interventions. This should reflect both the ‘generic’ and paediatric-specific causes suggested by this review. As mentioned above, qualitative study designs offer the potential to identify causative factors, and to explain how they lead to errors. Moreover, research should address the wide range of contexts in which paediatric prescribing occurs, including primary care. This review also suggests specific research topics, summarised in box 2.
Beyond further research, there is a need for more immediate action to reduce prescribing error. This review, in demonstrating how use of different formulations leads to error, supports efforts to standardise drug concentrations across practice settings.69 Governments, too, should work with the pharmaceutical industry to promote development of paediatric-specific products and ensure proper drug licensing. Medication dosing could be simplified by using age-banded instead of weight-based dosing,70 although further study is needed to confirm the effectiveness of this strategy. Novel formulations, too, show promising results.71
That many causes of errors are paediatric specific endorses the role of paediatric pharmacists, whose effectiveness in preventing errors has been shown in previous research.72 Increasing the availability of non-medical prescribers, with specific paediatric expertise, may also help. Children’s high reliance on individualised dosing, calculations and weight/volume conversions means that electronic prescribing, electronic health records and clinical decision support tools all have the potential to reduce errors.73 It is important to note, however, that computer systems do not prevent all errors74—and may generate new ones—and rely on paediatric-specific design and careful implementation.75 Putting in place rigorous systems to accurately record children’s weights could also help reduce errors.
Our findings indicate that education should be targeted at all doctors who have prescribing responsibility for children. Because so many doctors care for children as part of their job, this should begin at undergraduate level and continue in specialty training and as part of induction processes. The content of education should go beyond raising awareness that prescribing for children is different, to targeting the mechanisms by which differences lead to errors. High-risk aspects, in particular, such as calculations and weight-volume conversions, require specific focus. Given the complex, contextual nature of prescribing for children, classroom-based teaching should be supported with opportunities to prescribe in context with appropriate supervision. Providing feedback on prescribing practice, too, offers doctors the opportunity to reflect on their own prescribing and become more attuned to areas of risk.76
Prescribing decisions, however, are so contextual and nuanced that education alone will be insufficient to prevent errors. Improving support mechanisms, particularly for practitioners with less paediatric experience, will be needed. This might involve shared care arrangements with paediatric teams, or increasing the availability of paediatric pharmacist advice. Increasing error detection, too, has potential benefits. To support this, further research could clarify the effectiveness and most appropriate uses of double-checking processes.77 Investigating how children and parents can become more involved in medication safety is also a particularly valuable area of study.
Prescribing for children was summarised by a stakeholder: ‘The term ‘children’ that we’re using, as a single entity, isn't correct. It's a very broad, very complex group, ranging from a premature infant at the limit of viability, right through to teenagers—and that's in the spectrum of normal physiology, and in disease, and in response to medications…making it much more complex to prescribe accurately.’ This study analyses how these unique considerations lead to errors, and demonstrates the need for paediatric-specific education, research and policy.
We thank Richard Fallis for his assistance with literature searching.
Contributors RLC conceptualised the study, contributed to and supervised data collection, led the analysis, led the stakeholder consultation and wrote the manuscript. RLC is the guarantor of the work. OK led data collection and contributed to study design, analysis and writing of the manuscript. MDS contributed to data analysis and writing of the manuscript. MPT contributed to study design, analysis and writing of the manuscript. TD contributed to study design, data collection, analysis and writing of the manuscript. The corresponding author attests that all listed authors meet the authorship criteria and that no others meeting the criteria have been omitted.
Funding RLC’s Research Fellowship/PhD Studentship is funded by the Royal Belfast Hospital for Sick Children Research Fellowship. Queen’s University Belfast sponsored the research.
Disclaimer The funders had no role in the design, conduct or reporting of the research.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The Queen’s University Belfast School of Medicine, Dentistry and Biomedical Sciences Research Ethics Committee approved the stakeholder consultation (Ref 17.59).
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data comprise records of article selection, data extraction sheet and the anonymised stakeholder consultation transcript. We will supply relevant data on request.