diagramming patients’ views of root causes of adverse drug events in ambulatory care: an online...
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Patient Education and Counseling 62 (2006) 302–315
Diagramming patients’ views of root causes of adverse drug events in
ambulatory care: An online tool for planning education and research
Mary Brown a,b,*, Rowan Frost a,c, Yu Ko a,d, Raymond Woosley a,e
a University of Arizona Center for Education and Research on Therapeutics, Tucson, AZ, United Statesb Department of Communication, University of Arizona, United States
c Mel and Enid Zuckerman College of Public Health, University of Arizona, United Statesd Department of Pharmaceutical Sciences, University of Arizona, United States
e The Critical Path Institute, Tucson, AZ, United States
Received 26 September 2005; received in revised form 14 February 2006; accepted 14 February 2006
Abstract
Objective: Diagram patients’ views of the causes of adverse drug events (ADEs) in ambulatory care, examine characteristics of causes
reported by patients, and identify those that have been studied in the medical and social science literatures.
Methods: Twenty-two primary care patients were interviewed using a root cause analysis approach. Diagrams derived from interviews were
consolidated and displayed online as a composite interactive causal diagram. Patient-reported causes were compared to evidence in the social
science and medical literatures.
Results: Patients ascribed 164 causes to ADEs occurring through eight major pathways, including medication nonadherence, prescriber–
patient miscommunication, patient medication error, failure to read medication label/insert, polypharmacy, patient characteristics,
pharmacist–patient miscommunication, and self medication. Most frequently reported causes were intrapsychic and interpersonal in nature.
Most patient-reported causes have been studied, however, several practical and motivational antecedents lack research.
Conclusion: Conducting root cause analysis with patients reveals multiple logically linked aspects of medication safety in community
settings that merit further research and consideration in patient and prescriber education.
Practice implications: This causal diagram provides a broadly accessible planning tool for reducing ambulatory ADEs by showing a
comprehensive picture of potential causes, identifying causal factors supported by evidence, and disclosing likely consequences of change
efforts. Also, patient-centered medication safety strategies should address psychological andpractical barrierspatients face in their everyday lives.
# 2006 Elsevier Ireland Ltd. All rights reserved.
Keywords: Adverse drug event; Drug interactions (MeSH heading); Medication safety; Root cause analysis; Ambulatory care; Physician–patient communication
1. Introduction
Adverse drug events (ADEs) often occur outside of
hospital settings, yet medication errors have been investi-
gated primarily in acute care [1,2]. The limited research on
adverse drug events in ambulatory care is of concern in part
because prescription medicines are the most frequently used
therapeutic intervention in medicine. In 2004 in the US, 3.5
billion outpatient prescriptions were filled, averaging 12.0
* Correspondence to: Education Core, AZCERT, P.O. Box 24506, Tucson,
AZ 85724, United States. Tel.: +1 520 626 1631; fax: +1 520 626 5181.
E-mail address: [email protected] (M. Brown).
0738-3991/$ – see front matter # 2006 Elsevier Ireland Ltd. All rights reserved
doi:10.1016/j.pec.2006.02.007
prescriptions per person [3]. Nearly two-thirds of US
physician office visits in 2001–02 ended with a prescription
[4]. Medication nonadherence also contributes to adverse
outcomes, and vice versa. From 30 to 50% of patients with
chronic conditions do not take their medication as prescribed
[5] and a 2000 study revealed a 76% discrepancy rate
between the medicines patients were prescribed and the
medicines they actually took [6]. However because
ambulatory ADEs occur in medically unsupervised settings,
they often go unreported [1,7], rendering them less visible
and harder to detect than ADEs in hospital settings. Though
the impact of ADEs in ambulatory care is likely substantial,
it is poorly documented.
.
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315 303
Relatively few studies have demonstrated the incidence
and nature of ADEs in ambulatory settings [8]. Gurwitz et al.
[9] found that the overall rate of ADEs was 50.1 per 1000
person-years in a cohort of Medicare enrollees. Of 1523
ADEs identified during a 12-month period, 27.6% were
considered preventable. A prospective cohort study con-
ducted at four adult primary care practices revealed that of
661 patients who responded, 24.5% had ADEs, of which
11% were preventable [10].
The medical and social science literatures suggest that
ADEs in primary care settings may arise from a combination
of patient, provider and health care system factors [11,12].
Patient factors include literacy level [13,14], lack of health
information [15], beliefs and attitudes [16], multiple drug
use [7] and communication skills deficits [17]. Provider
factors include limited capacity to track medications, time
and technology constraints [18–20]. ADEs also may be
influenced by interpersonal factors such as prescriber–
patient communication [10] and environmental factors such
as access to health care or lack of money [17].
Most studies of ADEs in primary care focus on diagnosis,
treatment and delivery of services [21,22], and are based on
physician reports [12,23] which tend to be provider-
centered, and may differ from patients’ views. Kuzel
et al. [24] recently proposed obtaining patients’ perspectives
of problems in their health care associated with harm and
contrasting these with provider perspectives. The authors
argued that relying only on providers’ expert knowledge
may miss important information about the causes of
medication-related errors because medical experts are less
informed than patients about the antecedents of ADEs that
take place outside the medical setting [24]. Patients’ views
concerning the causes of ADEs can provide crucial insights
into the nature of ADEs in ambulatory care. Direct
experience makes patients primary information sources
for investigating why ADEs happen and for identifying
medication safety measures that are patient-centered.
Increasingly, professional and consumer organizations such
as the American Pharmacists Association and SOS Rx have
advocated for the importance of the patient’s role in
medication safety. Nevertheless, to date, studies that involve
patient input into medical errors in ambulatory care are
sporadic [21,22,25,26].
Also lacking is research on causal links to ADEs in
primary care [12,23], especially studies that involve patients
in causal analysis [24]. Without an understanding of the
chain of causal events, solutions may be inadequate. Root
cause analysis, a popular tool commonly used in health care
quality improvement [27], patient safety programs [28,29],
and public health planning and evaluation [30–33], could
identify how causes contribute to ADEs in ambulatory
settings. Root cause analysis involves a structured ques-
tioning process among key informants that identifies
underlying causes of adverse events, with the goal of
preventing their reoccurrence. By revealing probable causal
pathways leading to the problem and verifying them
empirically, root cause analysis enables investigators to
identify appropriate corrective or preventive actions [34].
The aim of this project was to produce a tool to identify
effective, patient-centered strategies to reduce ADEs in
ambulatory care by diagramming relationships among
causal factors from the patient’s perspective and distinguish-
ing factors that are documented in the medical and social
science literatures from those that are not. Where evidence is
sufficient, solutions can be tailored and targeted to most
effectively reduce ADE risk. Factors lacking evidence invite
further research.
2. Methods
Our method followed Renger & Titcomb’s Antecedent-
Target-Measurement (ATM) approach [35], which employs
an adaptation of root cause analysis as a diagnostic tool for
health program planning and evaluation. This approach
utilizes a series of individual interviews with key informants
to diagram the underlying causes, termed antecedent
conditions, contributing to a given problem. Unlike other
forms of root cause analysis that are typically conducted with
small groups, this approach produces the broadest array of
plausible causes with a small sample of informants and avoids
group interaction effects that influence individual opinions
[36,37]. Interview data are consolidated into a single
composite diagram that coherently represents informants’
views. As in Gano’s Apollo Root Cause Analysis [34], causes
identified by informants are checked for supporting evidence.
The completed diagram is used to identify areas to target
interventions and to measure their effectiveness.
The ATM method has been used with state, regional and
local health education agencies in the US, and was endorsed
for use by the national network of Area Health Education
Centers and Health Education Training Centers [38]. We
chose this method because our purpose was to develop a
similar tool for applying health education efforts to reduce
adverse drug events in ambulatory care.
2.1. Participants
Twenty-two individuals (12 women and 10 men)
ranging in age from 18 to 70 years participated in semi-
structured interviews. Eligible participants included adult
primary care patients or caregivers for primary care
patients who had taken three or more prescription
medicines in the last five years. Selection criteria yielded
informants who have direct knowledge and experience in
taking prescribed medicines themselves or administering
them to relatives in their care. Participants were not
required to have experienced an ADE, which would have
predisposed them to systematic attribution biases [39–41].
Sample selection followed the ATM approach [35], which
holds that 10–12 interviews are sufficient to capture the
array of important antecedent conditions for health
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315304
problems. We doubled this number to ensure a broad range
of experience from both sexes.
We obtained a quota sample [42,43] approximating the
demographic profile of the adult population in Pima County,
AZ, which is typical of the US population in its diversity.
Quota categories included age and sex, which have been
associated with ADEs [44–49]. We also included ethnicity,
annual income and urban/rural status because these
characteristics have a potential impact on how people take
prescription drugs, their access to health care, and their
ability to pay for prescriptions [17,50,51].
Informants were recruited through face-to-face contact,
referrals from health care providers and prior informants,
and flyers in primary care clinics. Informants were enrolled
if they met both the study eligibility requirements and the
quota sample characteristics profile. Of the 24 individuals
contacted who met eligibility criteria, two men declined to
participate. It is not known whether the refusers were
different from male participants.
2.2. Procedure
2.2.1. Individual causal diagrams
The diagramming procedure followed the ATM approach
[35]. Diagrams were created during 50-minute individual
interviews conducted by an interviewer and a note taker. The
interviewer asked questions and drew the diagram on easel
Fig. 1. Initial steps in developing
paper as the informant responded while the note taker
recorded the informant’s statements on a laptop computer.
Two trained female researchers switched roles on a regular
schedule to offset personal attribute effects.
The interviewer first briefly described the problem: that
ADEs occur in the daily lives of primary care patients, and
explained our purpose: to understand patients’ views of the
reasons why these events happen. ADEs were defined as
illness or other negative effects caused by a prescribed drug,
such as a reaction to a drug or a reaction caused by drugs that
interact with each other. Informants were then asked a series
of up to five ‘‘why’’ questions to yield a chain of causes
leading to the problem [27,35]. The question ‘‘why does this
condition occur, based on your experience?’’ was asked for
the original problem statement and for each successive
reason given. We did not limit answers to preventable causes
because such evaluative activity would interfere with the
idea generation process. Also, we asked informants not to
speculate about prescriber or pharmacist behavior. The
‘‘why’’ question was repeated until the informant knew of no
further unambiguous reasons contributing to the outcome.
Working backwards to more distal causes, the interviewer
diagrammed causal relationships on easel paper, linking
reasons to their outcomes as informants responded to
questions, so that informants could see the logic of their
responses and make modifications if needed [29]. This
process yielded a set of antecedent conditions in logical
individual causal diagrams.
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315 305
Table 1
Comparison of sample and county characteristics
Category Sex Percentage
of sample
(N = 22)
Percentage
in countya
Percentage
women
(n = 12)
Percentage
men
(n = 10)
Age group
18–34 years 9 9 18 32
35–54 years 27 23 50 43
55–74 years 18 14 32 25
Annual income
Less than $25,000 9 9 18 33
$25,000 to $50,999 23 9 32 32
$51,000 or more 23 27 50 35
Ethnicity
Hispanic/Latino 18 14 32 29
White 18 27 46 61
African American 9 5 14 3
Native American 5 0 5 3
Other 5 0 5 4
Urban 46 46 91 87
Rural 9 0 9 13
Children living
at home
18 14 32 28
Caregiver of relative
or friend
32 14 46 –b
a Data source: U.S. Census Bureau, Census 2000. Retrieved July 29,
2003, from http://censtats.census.gov/data/AZ/05004019.pdf.b No statistics available.
paths leading to the problem. As in the ATM approach [35],
the term ‘‘antecedent condition’’ refers to any cause leading
to an outcome. (At times this term is shortened to
‘‘antecedent’’ or ‘‘condition’’ for brevity.) The questioning
process is illustrated in Fig. 1.
The interview diagram was redrawn using Microsoft1
PowerPoint1 and a text summary of the interview was
prepared from the note taker’s records. Within two weeks of
the interview, informants were mailed the printed Power-
Point1 copy of their causal diagram, the interview summary,
and a one-item questionnaire asking which three antecedent
conditions they thought were the most important con-
tributors to ADEs in community settings. Informants
answered the question, checked the diagram and summary
for accuracy and made any necessary corrections, and
returned the completed materials in a stamped self-
addressed envelope. Informants’ corrections, if any, were
incorporated into their diagrams.
2.2.2. Data reduction and analysis
Contents of individual causal diagrams were categorized
systematically and consolidated into one composite diagram
representing respondents’ collective attributions for ADEs in
a single coherent framework. We followed the ATM
consolidation procedure [29], employing qualitative methods
of analytic induction [52–54] and category generation
[55,56]. Consolidation was performed jointly by the two
interviewers plus a third analyst, and occurred in three stages.
Antecedent conditions in the first six individual diagrams
were reviewed by each analyst independently, and then
categorized into causal paths through discussion and
consensus, forming a preliminary composite diagram that
incorporated all conditions. This analytic process was
repeated incrementally in two more steps, after completion
of 15 interviews and again after 22 interviews. The composite
diagram was adjusted and expanded at each step to
incorporate all conditions in appropriate logical paths. Using
shared observation, discussion and consensus, analysts sought
to accurately represent respondents’ content and reasoning
structures so that an integrated model of respondents’ implicit
theories could emerge. Data reduction followed three guiding
principles: preserve accuracy in summarizing informant
observations; retain discrete conditions and logical connec-
tions made by informants; and seek parsimony.
Antecedent conditions in the composite diagram and
questionnaire responses were coded and entered into SPSS
12.0 [57] for descriptive analysis. Antecedents were
categorized and counted by causal path, by type, and by
sex to identify underlying patterns in the data. Paths were
defined as networks of logically related conditions. Thus,
paths organized conditions into chains of related causes.
Paths were named according to the antecedent condition
most proximal to the problem. Types were defined by the site
in which the condition arises: personal (within the person),
interpersonal (the interaction between persons) and envir-
onmental (the situation or circumstances surrounding
individuals). Types revealed where causes predominately
occur.
2.2.3. Linking patient-reported antecedents to evidence
Preliminary searches of the medical and social science
literatures were conducted to find documented evidence for
patient-reported conditions in the composite diagram.
Biomedical research was searched via Medline (1966-
present) using PubMed. Social science literature was
searched via PsycINFO, Academic Search Premier, and
Communication & Mass Media Complete using EBSCO-
host. Searches were based on keyword combinations derived
from patient-reported conditions and from language used in
the literature. Searches were limited to refereed journals.
Brief research summaries were developed for each causal
path in the diagram. For clarity and easy access, the
composite diagram was converted to an interactive format
using Flash1 software and posted on the Arizona Center for
Education and Research on Therapeutics website (www.az-
cert.org). Conditions for which evidence was found were
highlighted and linked to the citation lists with hyperlinks to
abstracts in PubMed, if available. Because literature
searches were time limited, we added dynamic links to
PubMed searches using keywords to access Medline
literature published from January 2004 to the present.
These links, developed with the assistance of medical
librarians, provide a built-in research updating mechanism.
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315306
3. Results
3.1. Participants
Demographic characteristics of participants were similar
to those for Pima County, with some exceptions (see Table 1).
Fig. 2. Abridged causal diagram of patient-reported conditio
Compared to county age statistics, the sample was older, with
68% of participants 35 years or older. Participants were
generally higher in income than county residents, with half
reporting annual incomes of greater than $51,000. Partici-
pants were ethnically diverse, and one-third had children
living at home. Almost half described themselves as
ns leading to adverse drug events in ambulatory care.
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315 307
Fig. 3. Causal Diagram Path 5: Patient takes multiple drugs that interact.
caregivers of relatives, including children, to whom they
administered medications.
3.2. Causal paths
Eight causal paths with 164 antecedent conditions
emerged in the composite diagram. Fig. 2 presents an
abbreviated version of the diagram, showing the eight
logical paths, plus antecedent conditions contained in each
logical path. Fig. 3 displays one complete logical path in the
diagram. The complete causal diagram is presented online at
www.azcert.org/consumers/logicModel/logicModel.htm.
Readers are asked to view it and to assess its interactive
capabilities. Because the diagram’s complexity makes it
impractical to exhibit in print, we have reproduced
highlights of the results in narrative and tabular form here
to illustrate noteworthy patterns in the data. Antecedent
conditions that also serve as path names are capitalized to
avoid ambiguity. These results are best understood by
referring to the above-referenced figures.
3.3. Most frequently reported antecedents
Twenty antecedents in five causal paths were cited by
more than 25% of informants (Table 2). The four most
frequently reported conditions resided in the paths,
Miscommunication between doctor and patient, and Patient
does not read medication instructions. The three most
frequently reported conditions with the greatest number of
antecedents were Miscommunication between doctor and
patient (n = 47), Patient does not follow medication
instructions (n = 41), and patient does not ask questions
or give information to doctor (n = 40). Among the top 10
most frequently reported conditions, three also were listed as
most important contributors to ADEs (Table 2). Together,
the paths, Patient does not follow medication instructions
and Miscommunication between doctor and patient, con-
tained 80% of the most frequently reported conditions.
3.4. Condition types
Most antecedent conditions reported were personal in
nature (66%), followed by environmental (37%). As shown
in Table 2, the most frequently cited personal conditions
were fear of embarrassment or negative reaction from doctor
(82% of informants), patient is not able to understand Rx
materials/oral instructions (64%), and patient does not
follow Rx instructions (46%). The most frequently cited
interpersonal conditions were patient does not ask questions
or give information to doctor (50%), doctor does not ask
questions or give information to patient (46%) and
Miscommunication between doctor and patient (46%). Only
two of the top 20 conditions reported were environmental:
Rx materials are difficult to read (55%) and patient is unable
to afford adequate health care (36%). However, respondents
identified 12 conditions in 3 major paths related to inability
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315308
Table 2
Most frequently reported antecedent conditions leading to adverse drug events in primary care patients by type, path, number of antecedents and sex, in rank
order
Antecedent condition Typea Pathb Number of
antecedentsc
Sex Total sample
(%)Women (%)
(n = 12)
Men (%)
(n = 10)
Patient is afraid of embarrassment or negative reaction from doctor P 1 11 75 90 82
Patient is not able to understand Rx materials/oral instructions P 4 2 58 70 64
Rx materials are difficult to read E 4 1 42 70 55
Patient does not ask questions or give information to doctord I 1 40 42 60 50
Patient does not follow Rx instructionsd P 2 41 42 50 46
Doctor does not ask questions or give information to patient I 1 0 42 50 46
Miscommunication between doctor & patientd I 1 47 50 40 45
Patient does not read label or insert P 4 14 33 50 41
Patient knowingly takes too much or too little of Rx P 2 13 50 30 41
Patient sees more than one doctor P 5 4 42 40 41
Patient forgets to follow Rx instructions P 2 4 33 40 36
Patient is unable to afford adequate health care P, E 1 1 42 30 36
2 0
3 5
Patient is not aware of adverse drug interactions
when combining medications
P 5 4 25 50 36
Patient is cognitively impaired P 1 5 25 40 32
Patient takes multiple medications that interact P 5 14 50 10 32
Patient trusts or expects doctor to know what to do P 1 0 33 30 32
Patient is addicted or abuses drugs or alcohol P 2 0 33 30 32
3 2
Patient is not motivated to follow Rx instructions P 2 7 42 10 27
Patient and doctor differ in culture or primary language I 1 0 33 20 27
2 0
3 0
a Type indicates the nature of antecedent condition: P: personal, I: interpersonal, E: environmental.b Numbered paths are composed of logically linked antecedent conditions (see Fig. 2).c 0 antecedents indicates a condition for which no further reasons were provided.d Listed as most important by three or more informants.
to obtain prescriptions or medical care due to poverty, lack
of access to basic medical care, or inadequate insurance
coverage.
Paths containing the greatest number of personal
conditions were Patient does not follow instructions
(n = 31) and Miscommunication between doctor and patient
(n = 34). The latter path contained the greatest number of
interpersonal conditions (n = 16). Paths containing the
greatest number of environmental conditions were Patient
does not follow prescription instructions (n = 14), Patient
self medicates (n = 12) and Miscommunication between
doctor and patient (n = 11).
3.5. Most important conditions
Informants listed up to three antecedent conditions
contained in their diagram that they considered most
important. Responses were distributed across 49 conditions.
Counts were too small to be meaningful; however, some
trends are noteworthy. The three conditions most commonly
listed as highest in importance were Patient does not follow
medication instructions, patient does not ask questions or
give information to doctor, and Miscommunication between
doctor and patient. The majority of high-importance
conditions were personal in type. The path Miscommunica-
tion between doctor and patient was most frequently
represented in this group, followed by the paths, Patient
takes multiple drugs that interact and Patient does not read
medication label or insert.
3.6. Evidence for patient-reported conditions
Preliminary searches of the social science and medical
literatures revealed, overall, evidence for a majority (57%)
of patient-reported antecedents to ADEs in ambulatory care.
Paths in which over two-thirds of reported conditions were
found in the literature were Patient takes wrong medication
(100%), Patient self medicates without doctor Rx (76%), and
Patient does not follow medication instructions (69%). The
lowest proportion of informant-reported conditions found in
the literature occurred in the paths, Miscommunication
between doctor and patient (46%), Patient does not read
medication label or insert (40%), and Patient takes multiple
drugs that interact (40%). Results are shown in Table 3.
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Table 3
Comparison of patient-reported conditions that could lead to adverse drug events in ambulatory care and evidence found in social science and medical literatures
Causal path
(total number of
antecedent conditions
in path)*
Antecedent conditions found in literature Number
(percent) of
antecedent
conditions
found in
literature
Antecedent conditions not found in literature Number
(percent) of
antecedent
conditions
not found
in literature
1. Miscommunication
between doctor and
patient (48)
Miscommunication between doctor & patient; Patient is distracted when
talking with doctor; Patient does not ask questions or give information to
doctor; Doctor does not ask questions or give information to patient;
Patient & doctor differ in culture or primary language;
Patient does not take responsibility for his/her own health;
Doctor seems rushed; Patient lacks ability to communicate;
Doctor-centered communication (doctor controls the interaction,
inhibits patient); Patient assumes doctor will tell him/her what to do;
Patient trusts/expects doctor to know what to do; Patient politeness/
fear of being rude or inappropriate; Patient is afraid doctor will
discontinue medicine; Patient lacks a relationship with doctor;
Patient is discouraged or offended by doctor;
Patient lacks language or education to explain (low health literacy);
Doctor’s gender is a problem for the patient; Patient is using
alternative medicine or other doctors; Doctor acts paternalistic/
patronizing; Patient feels doctor is not listening to needs or
providing desired social support; Patient lacks ability
to evaluate medical or health information; Patient forgets to
tell the doctor or ask questions about health problems.
22 (46%) Patient is busy/in a hurry, just wants appointment to end; Patient is trying to
assimilate diagnosis; Patient is caring for child(ren); Patient is not motivated to
give doctor information or ask questions; Patient triages self, prioritizes
information that will be disclosed to doctor; Patient thinks information or symptom
is not relevant or important; Religious or cultural prohibitions; Patient is
embarrassed or fears negative reaction from doctor or negative consequences;
Patient lacks money to deal with all health problems; Patient has cognitive
impairment (age, illness, etc.); Patient does not anticipate problems with health
issues; Patient does not think of herbs, supplements, OTC medicines as drugs;
One symptom is masked by another; Patient would have to refer to specific, private
body parts (e.g., genitalia, rectum); Patient believes his/her behavior contributes to the
condition; Patient does not want anyone to know about condition; Condition carries
social stigma; Patient could lose job or insurance coverage; Distractions—too many
things to do, too much to remember; Length of time between making appt. & visiting
the doctor; Patient lacks support system (friends, family) to assist in communicating;
Patient takes medicine only occasionally; Medicine or condition is not related to this
doctor visit; Patient fears he/she cannot stop the behavior; Condition affects patient’s
self-image or self-esteem; Patient fears if condition is in medical record, it could be
seen by employer or insurance co.
26 (54%)
2. Patient does not
follow medication
instructions (42)
Patient does not follow medication instructions; Patient is
not motivated to follow instructions; Patient is not able to follow
instructions; Patient forgets to follow instructions; Patient knowingly
takes too much or too little medicine; Patient does not feel
like medicine is working; Patient discovers side effects,
etc. that doctor did not mention; Patient is concerned
about long-term use/addiction; Patient disagrees
with doctor’s diagnosis/directions; Patient does not want to make
lifestyle changes; Patient dislikes taking medicine; Refuses medication
(e.g., children, cognitively impaired); Patient cannot take medication
in prescribed formulation (pills, liquid, injection);
Contradictory instructions for multiple prescriptions;
Patient does not understand instructions; Medication schedule
conflicts with busy personal/family/work schedule; Patient feels
better; Patient lacks resources (money, transportation);
Patient thinks taking more medication will make them well
quicker; Patient does not want to be impaired;
Patient feels better/has fewer side effects when taking lower dosage;
Side effects are embarrassing, inconvenient, too severe;
Patient thinks he/she does not need medicine every day;
Patient thinks doctor did not spend enough time with them to make
accurate diagnosis; Cultural/language barriers;
Patient has variable or unusual daily routine; Insurance does not
cover medication; Patient is substance abuser; Patient has responsibilities
(e.g., parent, pilot) and must be able to function.
29 (69%) Medication is diverted; Difficult to comply with school rules for administering
medicines to children; Patient feels too ill; If homeless, no place to store
medicines; Patient wants to get high; Following instructions is emotionally
draining, depressing; Family members/caregivers take medicine away; Patient sells
or shares medicine with others; Patient cannot get prescription filled; Patient may
be sleeping/not hungry when it is time to take medication; Medication causes
exhaustion; Patient cannot be spontaneous; Prescription runs out before insurance
allows refill.
13 (31%)
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10Table 3 (Continued )
Causal path
(total number of
antecedent conditions
in path)*
Antecedent conditions found in literature Number
(percent) of
antecedent
conditions
found in
literature
Antecedent conditions not found in literature Number
(percent) of
antecedent
conditions
not found
in literature
3. Patient self medicates
with herbs, OTC or
prescription drugs
without doctor
Rx (21)
Patient self medicates with herbs, OTC or prescription drugs without
doctor Rx; Patient lacks accurate information about health and
medication effects and contraindications; Patient is unable to afford
adequate health care; Patient is not able to see doctor;
Self medication is less expensive than going to doctor;
Patient does not want to see doctor; Doctor does not give
patient medication he/she wants; Patient takes old medicine he/she
has on hand; Patient lacks resources or access to care; Former
prescription drug is now OTC with higher cost than insurance copay;
Religious or cultural issues; Patient dislikes or distrusts doctors,
exams, or health care system; Patient lives in rural area with few doctors,
limited transportation; Patient lacks insurance or has inadequate coverage;
Patient has had previous bad experience or denial of treatment.
16 (76%) Patient abuses or is addicted to drugs/alcohol;
Patient is depressed/suicidal; Patient is lazy or unwilling to
spend money; Patient fears violation of privacy; Patient is poor
or unemployed; Patient does not know about govt.
benefits or how to get them.
5 (24%)
4. Patient does not read
medication label
or insert (15)
Patient does not read medication label or insert; Patient is not
motivated to read labels/inserts; Materials are not very
readable (length, language, print size); Patient is not able to
understand labels/inserts; Patient is a non-reader;
Patient is visually impaired.
6 (40%) Patient does not care; Patient does not want to know about adverse effects;
Patient does not want to make lifestyle changes (not drink, not combine meds);
Patient feels too ill to read; Patient does not want to take the time to read;
Patient believes pharmacist will tell them what to do; Fear and denial:
patient wants to avoid anxiety, worry, stress, creating self-fulfilling prophecy;
Patient wants immediate relief; Patient is too busy to read.
9 (60%)
5. Patient takes multiple
drugs that
interact (15)
Patient takes multiple drugs that interact;
Patient combines OTC drugs with prescription drugs;
Patient has a complicated illness or multiple illnesses
requiring many prescriptions; Records are incomplete;
Patient sees more than one doctor; Patient is dissatisfied
with current doctor or wants second opinion.
6 (40%) Patient is not aware of possible ADEs when combining drugs;
Residential or at-home care caregivers do not exchange information;
Doctor gives samples; Patient goes to more than one pharmacy;
Patient has more than one set of records; Patient gets medicine
from friends; Doctor gives patient specific drug he/she requested
without cautioning patient; Patient gets care in more than one
location or in multi-provider clinic; Insurance coverage changes.
9 (60%)
6. Individual patient
characteristics affect
prescribing and
outcomes (10)
Individual patient characteristics affect prescribing and outcomes;
Patient’s physical characteristics & biochemical differences affect
medication reaction; Patient is allergic to medication; Body size varies
from ‘‘average’’ patient of dosing protocol; Lifestyle factors
(drinking, diet, etc.) affect medication action.
5 (50%) Dosage is too low/too high; Doctors experiment to get correct dosage;
Doctor prescribes high dose to treat problem quickly;
Condition is difficult to treat; Patient’s lifestyle is not stable
enough for long/complicated course of medication.
5 (50%)
7. Miscommunication
between pharmacist
& patient (10)
Miscommunication between pharmacist & patient; Patient does not
ask questions or give information to pharmacist; Pharmacist does not
ask questions of or give information to patient; Embarrassing
medical condition; Lack of privacy; Pharmacist assumes patient
has Rx information if they’ve taken the medicine before, whereas
patient or Rx information may have changed.
6 (60%) Patient & pharmacist cultures and/or primary languages differ;
Patient trusts pharmacist to dispense/advise properly;
Pharmacist seems rushed; Patient does not think to tell
pharmacist about non-prescription substances.
4 (40%)
8. Patient takes wrong
medication (3)
Patient takes wrong medication; Pharmacist dispenses wrong
medication; Patient mistake: medicines look similar.
3 (100%) 0 0
* Total includes antecedent conditions that also serve as major path names.
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315 311
Fig. 4. Selected factors affecting medical encounters before, during and after interaction, extrapolated from patient responses.
4. Discussion and conclusion
4.1. Discussion
The web-based causal diagram developed in this
investigation displays a holistic, explicit view of factors
potentially contributing to ADEs in ambulatory settings
from the patient’s perspective. The intricate causal chains of
factors are informative, and the online diagram has
promising utility as a planning tool for medical educators
and researchers. Practice implications suggest that for
effective, patient-centered medication safety strategies we
look beyond simple solutions to address psychological and
practical barriers patients face in their everyday lives,
particularly as they relate to prescriber–patient interaction.
Overall, the causal paths in the diagram indicate that the
current educational focus on deficits in health literacy [58–
62], adherence [5,63–68] and doctor–patient communica-
tion [11,69–74] is necessary but insufficient to reduce ADEs
in ambulatory care. Informants’ reports of emotions,
cognitions, motivations and practical barriers as equally
important contributors point to the need for further
investigation and for educational strategies that address
these factors. Further, the diagram illustrates the complex
interdependencies among factors potentially leading to
ADEs in patients’ lives. Recognizing these relationships is
important for facilitating safer medication practices among
ambulatory patients.
Especially important to consider is the central role
patients assigned to miscommunication as contributing to
ADEs. Prescriber–patient miscommunication factors were
considered among the most important, and they represent
30% of all factors identified by patients. The pervasiveness
of these factors occurring in the diagram affirms the
importance of expression, elicitation, and understanding in
exchanging information about prescriptions during medical
encounters already established in the literature
[16,71,72,75–77]. Importantly, 85% of the reported mis-
communication factors relate to the patients’ failure to give
information or ask questions of the prescriber. Of these, 45%
were related to their lack of motivation to disclose or ask for
information, including expecting the doctor to tell them
what to do, fear of negative consequences, fear of being rude
or inappropriate, and poor relationship with the doctor.
Another 17% of factors related to patients’ lack of ability to
ask or give relevant information to the doctor, including
forgetting, being distracted, cognitive impairment, and
lacking language or education to explain problems. (See
Fig. 4 for a model of how such factors affect interaction in
medical encounters.) With the increasing use of multiple
drugs for co-occurring conditions and a commensurate
increase in potential adverse prescribing outcomes, under-
standing the dynamics of underlying factors that interfere
with disclosure and accuracy of drug-relevant information is
vital to reducing ADEs. Yet over half of these patient-
identified factors were not found in the extensive literature
on doctor–patient communication, which spans more than
four decades.
By specifying patients’ views of relationships among
antecedent conditions, the online diagram offers explicit
guidance for education or practice changes to address the
problem of ADEs in ambulatory care from a patient-
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315312
centered standpoint. The causal chains show which
conditions are most likely to affect key outcomes in causal
pathways, thereby suggesting the most powerful conditions
to target for education. It allows viewers to determine which
conditions are most preventable, and/or most amenable to
education for patients or prescribers. It reveals where
evidence is strong and where further research may be
needed. In addition, it promotes realistic expectations
among planners and evaluators about the effect of
educational efforts by showing conditions that are so
multifactorial in nature that it is unreasonable to anticipate
change as a result of education alone [29]. For example, in
the Miscommunication between doctor and patient path,
patients reported 11 antecedents leading to fear of negative
reaction from doctor. To change this condition so that
patients will fully disclose relevant information, several of
its antecedents also must change. On the other hand, several
beneficial outcomes could occur from changing one key
antecedent. By avoiding the appearance of being rushed,
prescribers favorably impact patients’ motivation to ask
questions, their decisions about what to ask or disclose, their
actual disclosure of information, and their attitude toward
the prescriber and health care system.
We envision users applying the online tool by taking the
following steps, which are adapted from the work of Gano
[34] and Renger and Titcomb [35]. First, clarify the
meaning of causes in each path. Examine placement of
causes to uncover which precede others and which are
effects of others in causal chains. Signify the causes that are
corroborated by evidence. Working from left to right (from
distal to proximal causes), generate solutions to each cause.
Determine which causes are preventable (within voluntary
control), and identify actions involved in the solution.
Choose solutions that effectively prevent the causes from
occurring without causing other adverse effects, and that
provide the greatest value for the cost. Greatest value can be
determined by examining which causes have the most
effects in causal chains. Finally, design educational or
system interventions that target these causes and evaluate
their effectiveness.
Certain limitations of this research should be taken
into account. Our sample included fewer men than
women and informants were older and higher in income
than county residents. Therefore, their attributions for
ADEs in ambulatory care may not match those of the
broader population. To avoid predisposing informants to
systemic biases we avoided asking whether they had
personally experienced an ADE. Thus, our findings do not
distinguish between reports based on direct personal
experience and speculative attributions for patient-related
causes.
4.2. Conclusion
Root cause analysis utilizing 22 patients as key
informants revealed important relationships among ante-
cedents to guide patient-centered education for reducing
ADEs in community settings. Informants’ responses showed
that ADEs in ambulatory care result from multiple
interdependent antecedents, most of which are factors that
are amenable to patient and prescriber education. The
logical sequences suggest that the extensive research in the
areas of patient literacy, adherence, social support and
prescriber–patient communication covers many important
antecedents reported by patients, but misses several
psychological and practical factors in patients’ lives. The
qualitative method used in this analysis yielded logically
organized information about a complex problem as patients
see it. The resulting interactive diagram indicates promising
areas for further research and facilitates exploration of
relationships among antecedents and linkages to extant
research that can be easily accessed by geographically
dispersed audiences. We plan next to compare prescribers’
notions of root causes for ADEs with those of patients.
4.3. Practice implications
Over time this tool can guide education and research
efforts aimed at reducing ambulatory ADEs. By identifying
the complex interdependencies among conditions contribut-
ing to ADEs, this causal diagram clarifies the need for multi-
level interventions. Medical educators can use the diagram
in designing programs that pinpoint key factors in the causal
chains. Researchers can readily identify areas in which
research has been concentrated, and which areas need more
investigation. The diagram also provides documentation for
informing policy makers of the need for broad-based
programs in community settings.
For now, five implications emerge clearly from the data.
The conditions supported by evidence and their placement in
this diagram suggest the following:
1. S
imple recipe-like, action-oriented solutions are insuffi-cient to significantly reduce ADEs in community
settings. The Patient does not follow medication
instructions path suggests that educational interventions
for prescribers and patients would be more effective if
they address cognitive barriers in patients such as lack of
motivation, forgetting, and deliberate choices to deviate
from prescribed regimens. Similarly, efforts to improve
prescriber–patient communication would be more effec-
tive if they address patients’ motives for withholding
questions or information from the prescriber, and
recognize the influence of psychological and environ-
mental distractions on the patient (e.g., worry, fear,
embarrassment; time constraints).
2. B
eyond the well-recognized needs to improve patientliteracy and readability of inserts, several motivational
and environmental barriers can prevent patients from
reading medication instructions. Even if patients acquire
health literacy skills, they will not be used if patients lack
motivation to read carefully or are prevented from
M. Brown et al. / Patient Education and Counseling 62 (2006) 302–315 313
reading due to situational pressures. Addressing these
barriers through discussion and problem-solving with the
patient may increase the effectiveness of education aimed
at improving health literacy.
3. S
imple recommendations to check with one’s doctorbefore taking medications are naı̈ve. Antecedents in the
self medication path indicate that contacting health care
providers is unlikely if patients cannot afford to see the
doctor, feel alienated or distrustful of the prescriber or
health care system, seek immediate relief, abuse
prescription medications, are depressed, or lack informa-
tion about the risks of mixing drugs. Many of these
factors could be addressed by providing patients easy
access to a qualified, patient-centered medication
consultant via telephone or Internet, as do many larger
health care organizations.
4. A
mbulatory patients need to know about potential drug-drug interactions, and about the need to consider all types
of drugs they use—prescription, over-the-counter, herbs
and supplements, and recreational drugs including
alcohol and nicotine. Informants noted that patients
taking multiple drugs for complicated or multiple
illnesses are especially vulnerable to drug-drug interac-
tions, a phenomenon well documented in the literature
[45,78]. Raising patient awareness of the full spectrum of
prescription, non-prescription, and alternative medica-
tions they are taking and the importance of informing
their health care providers of all such drugs, could be
accomplished through targeted medication safety educa-
tion and pre-doctor visit patient questionnaires contain-
ing forced-choice questions about drug use across
multiple domains. Full disclosure about all drug use is
facilitated by a nonjudgmental, shame-free health care
environment [60].
5. E
ducational interventions should target both patients andprescribers. The personal and interpersonal nature of
most potential antecedents to ADEs suggests capitalizing
on the reciprocal influence occurring in prescriber–
patient interaction and effects of that interaction on
patients before and after the medical encounter (see
Fig. 4). Improving prescribers’ listening skills and
providing a safe, open, shame-free environment will
assist patients to disclose relevant information or ask
questions during doctor visits. In addition, increasing
patients’ willingness to disclose or ask questions will
prompt prescribers to discuss relevant material they
might not otherwise mention.
Acknowledgements
This project was supported by a grant (U18 HS10385)
from the US Agency for Healthcare Research and Quality to
the Arizona Center for Education and Research on
Therapeutics. The authors thank Gabriel Stahl and AHSL
librarians for their assistance.
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