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Accuracy of Primary Care and Hospital-Based Physicians' Predictions of Elderly Outpatients' Treatment Preferences With and Without Advance Directives
Kristen M. Coppola, PhD;
Peter H. Ditto, PhD;
Joseph H. Danks, PhD;
William D. Smucker, MD
Arch Intern Med. 2001;161:431-440.
ABSTRACT
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Background Past research has documented that primary care physicians and family
members are often inaccurate when making substituted judgments for patients
without advance directives (ADs). This study compared the accuracy of substituted
judgments made by primary care physicians, hospital-based physicians, and
family surrogates on behalf of elderly outpatients and examined the effectiveness
of ADs in improving the accuracy of these judgments.
Participants and Methods Participants were 24 primary care physicians of 82 elderly outpatients,
17 emergency and critical care physicians who had no prior experience with
the patients, and a baseline comparison group of family surrogates. The primary
outcome was accuracy of physicians' predictions of patients' preferences for
4 life-sustaining treatments in 9 hypothetical illness scenarios. Physicians
made substituted judgments after being provided with no patient AD, patient's
value-based AD, or patient's scenario-based AD.
Results Family surrogates' judgments were more accurate than physicians'. Hospital-based
physicians making predictions without ADs had the lowest accuracy. Primary
care physicians' accuracy was not improved by either AD. Accuracy and confidence
in predictions of hospital-based physicians was significantly improved for
some scenarios using a scenario-based AD.
Conclusions Although ADs do not improve the accuracy of substituted judgments for
primary care physicians or family surrogates, they increase the accuracy of
hospital-based physicians. Primary care physicians are withdrawing from hospital-based
care in growing numbers, and emergency medicine and critical care specialists
most often are involved in decisions about whether to begin life-sustaining
treatments. If ADs can help these physicians better understand patients' preferences,
patient autonomy more likely will be preserved when patients become incapacitated.
INTRODUCTION
ADVANCE DIRECTIVES (ADs) were created to ensure patient autonomy at
the end of life. Ideally, patients who became decisionally incapacitated in
their final weeks and days of life could still "voice" their preferences for
medical care through a prerecorded document, known as the living will, or
through a preappointed decision maker referred to as a proxy or surrogate
decision maker. Autonomy is preserved to the extent that life-sustaining treatment
decisions that physicians and family members make on behalf of the patient
(based on AD information) are the same decisions that the patient would have
made for himself or herself.
Considerable attention has been given to the difficulties associated
with implementing policies designed to encourage completion and use of ADs.
For example, surveys estimate that between 2% and 30% of Americans have actually
completed an AD.1, 2, 3
Even if patients do have an AD, physicians are unlikely to be aware of patient
preferences or of the existence of the document.4, 5
Other researchers have reported that ADs are often unavailable when treatment
decisions need to be made.6, 7, 8
Finally, even if the physician is aware of the AD, the document still may
be overruled by physicians or families who must make decisions for the patient,6, 9 possibly because the information contained
in the document is vague or not easily applied in clinical situations.10, 11
The fact that ADs are not usually completed, are not available when
decisions need to be made, or are ignored or overridden by physicians or family
members indicates that there is a problem with policy implementation. The
difficulties of policy implementation are shortcomings of "process" and do
not necessarily corrupt the underlying assumption of the ADs, which is whether
they contain information that can guide patient care and promote patient autonomy.
The little information that we know about the content of ADs and their value
as decision-making tools has been purely descriptive.10, 11
Although much research has documented that physicians and family members
are often inaccurate when making substituted judgments for patients without
ADs,12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26
until recently, no research had examined whether ADs improve the accuracy
of substituted judgment. In their article in this issue, Ditto and colleagues27 showed that substituted judgment decisions informed
by 1 of 2 types of ADs and enhanced with patient-surrogate discussion did
not improve the accuracy of family surrogates' substituted judgments. No research
has examined if ADs can improve the accuracy of primary care physicians asked
to make substituted judgments for patients. Arguably, physicians have a greater
need for AD information, since prior studies19, 20, 25
indicate that primary care physicians have poorer accuracy compared with family
members.
In addition, AD information may be particularly valuable for physicians
who do not have a close relationship with the patient or have not had the
opportunity to discuss treatment preferences with the patient. For example,
in the emergency department, physicians are often faced with life-sustaining
treatment decisions for patients with whom they have no preexisting relationship,
and for whom there is no designated or available surrogate.28
Indeed, as primary care physicians delegate their care of seriously ill patients
to hospital-based physicians, more decisions about initiation of life-sustaining
treatments will be made by physicians who do not know the patient. The previous
evidence concerning accuracy of decision making for well-acquainted surrogates
indicates that accuracy would likely be even lower for physicians who are
not acquainted with the patient. No research has examined the accuracy of
decisions made by hospital-based physicians for unfamiliar patients, how this
accuracy compares with primary care physicians' or family surrogates' accuracy,
or whether ADs play a role in informing these decisions.
This study had 2 major purposes. The first was to examine the accuracy
of substituted judgments made by hospital-based physicians for unfamiliar
patients in comparison to patients' primary care physician and family surrogate.
The second was to examine whether ADs can improve the accuracy of substituted
judgments made by primary care physicians and hospital-based physicians.
PARTICIPANTS AND METHODS
The Data for the present study were collected from physicians of patients
involved in phase 1 of the Advance Directives Values Assessment and Communication
Enhancement (ADVANCE) project, which examined the ability of ADs to improve
the accuracy of decisions made by family surrogates.27
Primary care physicians and hospital-based physicians made predictions about
the life-sustaining treatment preferences of a subset of phase 1 patients.
ELICITATION OF PATIENTS' PREFERENCES
Participants in phase 1 of the ADVANCE project were recruited from a
network of 6 group primary care practices, which included 24 primary care
physicians, affiliated with Summa Health System in Akron, Ohio. Randomly selected
patients 65 years or older were initially contacted by letter introducing
the study. Unless patients telephoned the project office to decline participation,
trained interviewers telephoned patients to solicit participation. Interviews
took place in the patients' homes and were approximately 1 hour long. A total
of 401 patients and their designated family surrogates were interviewed in
the ADVANCE project.
Patients completed the Life-Support Preferences-Predictions Questionnaire29 (LSPQ), which measures patient treatment preferences
across a broad spectrum of realistic life-sustaining treatment decisions.
The LSPQ began with descriptions of 4 life-sustaining medical treatments chosen
to vary in their invasiveness: (1) antibiotics, (2) cardiopulmonary resuscitation,
(3) gallbladder surgery, and (4) artificial nutrition and hydration. Patients
were read standard descriptions of the treatments including why the treatment
is provided and general risks and benefits of the treatments. Nine different
medical scenarios were described that were chosen to capture a broad range
of conditions varying in their severity, nature of impairment (eg, cognitive
vs physical), prognosis, and level of pain: (1) the patient's current health
(current health); (2) Alzheimer disease with moderately severe cognitive impairment
and a certain but indeterminate rate of decline (Alzheimer disease); (3) emphysema
with constant shortness of breath, severe physical limitations, and a certain
but indeterminate rate of progression (emphysema); (4) coma persisting 6 weeks
after a stroke with no obvious cognitive abilities, indeterminate rate of
decline, and physician opinion of no chance of recovery (coma no chance);
(5) the same coma scenario as in scenario 4 with a physician opinion of a
very slight chance of recovery (coma slight chance); (6) stroke resulting
in partial paralysis, language deficits, total dependence in activities of
daily living, and physician opinion of no chance of improvement (stroke no
chance); (7) the same stroke scenario as in scenario 6 with a physician opinion
of a very slight chance of improvement (stroke slight chance); (8) terminal
colon cancer with fatigue, no pain, and a life expectancy of 6 months (cancer
no pain); and (9) the same cancer scenario as in scenario 8 with pain that
requires the constant use of medication to control symptoms (cancer with pain).
In the patient version of the LSPQ, patients imagined themselves in
each medical scenario and indicated their preference for receiving each of
the 4 medical treatments (in the current health scenario, the artificial nutrition
and hydration question was omitted). Patients indicated their treatment preferences
using a 5-point Likert scale: "definitely don't want treatment," "probably
don't want treatment," "unsure," "probably want treatment," and "definitely
want treatment." Surrogates were asked to imagine the patient in each medical
scenario and predict the patient's treatment preferences using the same 5-point
scale.
SURROGATES' PREDICTIONS OF PATIENTS' PREFERENCES
Family Surrogates
A subsample (n = 82) of family surrogates from the phase 1 study were
used as a baseline comparison group with primary care physician and hospital-based
physician accuracy. These surrogates were chosen by the patients in the phase
1 study as the individual whom they would want to make medical decisions for
them if they were no longer able. The majority of family surrogates were spouses
and adult children of patients. However, "family" is used in a broad sense,
including friends and clergy.
As a part of the phase 1 study, patients and family surrogates were
randomly assigned to either a control condition in which they did not complete
an AD (no-AD) or 1 of 4 intervention conditions in which surrogates made predictions
after exposure to a patient-completed AD (completed with or without discussion
with the surrogate). The 4 phase 1 intervention conditions were created by
the orthogonal application of 2 intervention components: (1) "type of AD,"
family surrogates were provided with either a scenario-based AD (the health
care directive [HCD]30, 31) or
an outcome-based AD (the valued life activities directive [VLA]32)
and (2) "opportunity for discussion," family surrogates either were provided
with the directive without the opportunity to discuss its contents with the
patient or were present when the patient completed the AD and were encouraged
to discuss the directive with the patient. (Copies of both ADs, as well as
a full description of all phases of the ADVANCE project can be obtained from
the author, P.H.D., on request.)
The family surrogates reviewed the patient's AD (when applicable), made
predictions on the LSPQ regarding patient preferences, and rated how confident
they were that they accurately predicted the wishes of the patient on a 5-point
scale.
Primary Care Physicians
All of the primary care physicians (N = 24) from the primary care practices
affiliated with Summa Health System were contacted and agreed to participate.
Each primary care physician was to complete 5 substituted judgment tasks:
predicting preferences of 1 patient who did not complete an AD (the no-AD
condition), predicting preferences of 2 patients who had completed the VLA
(1 patient who had completed the VLA with discussion with their family surrogate
and 1 who had completed the VLA alone), and predicting preferences of 2 patients
in the HCD condition (1 patient who had completed the HCD with discussion
with their family surrogate and 1 who had completed the HCD alone). Primary
care physicians were told the name of the patient whom they would be making
substituted judgments for and were asked to answer questions regarding their
relationship with that patient (eg, "How long have you been seeing this person
as a patient?"). Four patient names were not recognized by primary care physicians
and were not included in the study. Physicians were then instructed to review
the patient's AD (in the VLA and HCD conditions) and to predict their patients'
preferences for life-sustaining treatment on the LSPQ. Those in the AD conditions
had the option of reviewing the patient's directive at any time during the
completion of the LSPQ. After completing the LSPQ, the physicians rated how
confident they were that they accurately predicted the wishes of the patient
on a 5-point scale and how helpful they found the AD. This procedure was then
repeated with another patient until the physician had made substituted judgments
for 1 patient from each of the 5 phase 1 conditions.
Because patients were randomly assigned to a study condition in phase
1, not all primary care physicians had patients in each of the 5 study conditions.
In addition, 47 (12%) patients indicated on a question from their phase 1
participation that they did not want their AD shared with their physician.
Because the "discussion" conditions did not directly apply to the physicians
(ie, the physicians only reviewed the patients' ADs and were not present for
discussion when the patient completed the VLA or HCD documents) having them
make predictions using ADs created from discussion was not essential. To maximize
the number of physician predictions, physicians without 5 unique prediction
conditions completed as many unique condition interviews as possible, with
the goal of having predictions for 1 no-AD patient, 2 HCD patients (either
discussion or no discussion), and 2 VLA patients (either discussion or no
discussion) (Figure 1).
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Figure 1. Study design. ADVANCE indicates
Advance Directives Values Assessment and Communication Enhancement; VLA, valued
life activities directive; HCD, health care directive; and AD, advance directive.
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Thirteen primary care physicians completed judgments for 5 patients.
The following list describes the remaining patient judgments: 1 physician
completed judgments for 4 patients, 1 physician completed judgments for 3
patients, 3 physicians completed judgments for 2 patients each, and 5 physicians
completed judgments for 1 patient each. The total number of predictions were
83, although 1 patient was subsequently not included in the study due to incomplete
data.
Hospital-Based Physicians
Phase 1 of the ADVANCE project had enrolled physicians and patients
from 2 hospitals associated with Summa Health System. Physicians from these
hospitals who specialized in emergency or critical care medicine (n = 17)
and spent at least 50% of their time working in a hospital setting were contacted
by letter to participate. Each hospital-based physician was yoked to 1 or
more primary care physicians to complete predictions for 1 patient in each
of the 5 possible AD conditions. For example, if primary care physician 1
had completed predictions for 1 patient in all 5 conditions, then hospital-based
physician 1 would complete predictions for the same 5 patients. However, if
primary care physician 2 only made predictions for 2 patients in the HCD condition,
then hospital-based physician 2 would make predictions for those 2 patients
in addition to predictions for another primary care physician's patients who
were in the no-AD and VLA conditions. Therefore, fewer hospital-based physicians
were needed to complete all of the predictions.
Hospital-based physicians were provided with basic demographic information
about each patient (ie, age, sex, and race) but were blinded to patients'
names. They then reviewed the patient's AD (when applicable) and made predictions
on the LSPQ regarding patient preferences. After completing the LSPQ with
predictions of the patient's preferences, the hospital-based physicians also
rated how confident they were that they accurately predicted the wishes of
the patient on a 5-point scale and whether they found the AD helpful.
STATISTICAL ANALYSIS
Patients' and surrogates' responses on the LSPQ were dichotomized into
"want treatment" ("definitely want treatment," "probably want treatment,"
or "unsure") and "don't want treatment" ("probably do not want treatment"
and "definitely do not want treatment") responses for each of the 35 treatment
decisions. On the basis of past research, "unsure" responses were categorized
with "want treatment" responses because in most instances the clinical default
is to provide treatment unless specifically refused.17, 20, 24, 25
Analyzing data excluding "unsure" responses, treating "unsure" as a third
response category, and treating "definitely" and "probably" as separate response
categories produced no significant differences in study results. Proportion
scores were generated for preferences and predictions made in each scenario
(by summing the number of "want treatment" responses within each scenario
and dividing by the number of treatment decisions in that scenario).
Three measures were generated as indicators of the accuracy of substituted
judgments. Predictions were defined as accurate if, for a given treatment
decision, the surrogate gave the same dichotomized response as the corresponding
patient. Inaccurate predictions were further categorized into "overtreatment
errors" (surrogate predicted the patient would want treatment and patient
did not want treatment) and "undertreatment errors" (surrogate predicted patient
would not want treatment and patient wanted treatment). Two approaches were
used to compare the proportion of accurate predictions and of each type of
prediction error across the 3 collapsed study conditions (ie, no-AD, HCD,
VLA). First, an overall index was created by summing the number of accurate
predictions (or alternatively, the number of overtreatment or undertreatment
errors) for all treatments in all scenarios and dividing by the total number
of predictions. Second, scenario indexes were created by summing the number
of accurate predictions (or alternatively, the number of overtreatment or
undertreatment errors) within each scenario and dividing by the number of
treatment decisions in that scenario.
The overall ability of primary care physicians, hospital-based physicians,
and families to predict patients' treatment preferences was examined initially
with repeated measures analyses of variance (ANOVAs) using the overall accuracy,
overtreatment, and undertreatment indexes (ie, collapsed across all scenarios
and treatments). When significant differences were found for an overall index,
individual scenario indexes were then examined. Post hoc comparisons were
then conducted using paired t tests with a Bonferroni
correction for multiple comparisons.33
Next, accuracy by AD condition was examined for the 2 physician groups.
A repeated-measures ANOVA with 1 within-subjects factor (type of physician)
and 1 between-subjects factor (AD condition) was conducted on overall proportion
accuracy, overall overtreatment, and overall undertreatment scores. For the
between-subjects factor, Dunnett post hoc comparisons were used to examine
differences between the means within each group. For the within-subjects factor,
paired t tests with a Bonferroni correction were
used for post hoc comparisons. When significant differences were found for
an overall index, individual scenario and treatment indexes were then examined.
Identical analyses and post hoc comparisons were conducted on the confidence
measure for physician group by AD condition. To evaluate the extent to which
significant results could be accounted for by within-physician variation,
intraclass correlations were computed for those ANOVAs showing between-group
differences. Since all intraclass correlations were nonsignificant, it is
unlikely that within-physician variance significantly altered the present
results.
RESULTS
SAMPLE CHARACTERISTICS
Descriptive information about primary care physicians, hospital-based
physicians, and family surrogates is presented in Table 1. Primary care physicians were on average 39.8 years old
and 59% were male. Most of the primary care physicians were European American
(87.5%), married (87.5%), and had been trained as family practice physicians
(79.2%). The majority of primary care physicians (76.4%) reported having made
life-sustaining medical treatment decisions (ie, to withhold or withdraw treatment)
less than 10 times in the past year. Approximately 24% of primary care physicians
reported that they had an AD. The primary care physicians had seen the majority
of patients in the sample (96.4% of patients) at least once in the past year
and about half of the patients had been seen multiple times during the past
year.
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Table 1. Demographic Characteristics of Sample*
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Similar to the primary care physicians, the hospital-based physicians
had a mean age of 39.2 years, were European American (100%), and married (82.4%).
Eighty-eight percent were male and the majority (70.6%) specialized in emergency
medicine. Hospital-based physicians spend on average 94% of their time working
in a hospital setting (range, 60%-100%). Compared with primary care physicians,
a higher percentage of hospital-based physicians (35.7%) reported having an
AD. The majority of hospital-based physicians (64.7%) reported having made
life-sustaining medical treatment decisions (ie, to withhold or withdraw treatment)
more than 50 times in the past year.
The demographics of the subsample of family surrogates did not significantly
differ from those of the original sample of 401 family surrogates from the
phase 1 study.27 Unlike the physician groups,
the family surrogates had a mean age of 62.7 years and the majority were female
(64.6%). The majority of family surrogates were European American (91.5%),
married (87.8 %), and of the Protestant faith (59.8%). Patients and family
surrogates had known each other for an average of 45 years. Information about
ADs of these surrogates was not collected.
OVERALL ACCURACY OF SURROGATES' PREDICTIONS
We first examined the overall accuracy of predictions of patient preferences,
as well as accuracy in predictions by type of scenario for primary care physicians,
hospital-based physicians, and family surrogates. To do this, we collapsed
accuracy scores across the intervention conditions. These means are reported
in Table 2. Overall, primary care
physicians and hospital-based physicians were only accurate for an average
of 0.66 and 0.64 of treatment decisions, respectively (Table 2), although accuracy scores differed by scenario. Accuracy
scores were highest for "extreme" scenarios (ie, current health, coma with
no chance of recovery, and terminal cancer with pain) when most patients wanted
all or none of the treatment options.
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Table 2. Proportion of Accurate Predictions, Overtreatment Errors,
and Undertreatment Errors by Surrogate*
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When we compared the accuracy of the physician groups and family surrogates,
we found differences for overall accuracy (F2,162 = 12.02, P<.001), and accuracy for the emphysema, stroke with
no chance of recovery, stroke with a slight chance of recovery, cancer with
no pain, and cancer with pain scenarios (all P<.05).
Post hoc comparisons indicated that for overall scores, family surrogates
were more accurate than both physician groups, while the 2 physician groups
did not differ from each other. For emphysema, stroke with a slight chance
of recovery, and cancer with no pain, family surrogates were more accurate
than both physician groups. For the remaining 2 scenarios, only family surrogates
were significantly more accurate than the hospital-based physicians.
We next examined the types of errors made by the primary care physicians,
hospital-based physicians, and family surrogates. In Table 2, family surrogates primarily made overtreatment errors;
primary care physicians consistently made undertreatment errors. Hospital-based
physicians made both types of errors, with slightly more being overtreatment
errors. Overtreatment errors are slightly masked in Table 2 because means are collapsed across AD conditions.
Comparing overtreatment errors across surrogate type, an overall difference
was found (F2,162 = 6.76, P<.01), as
well as individual scenario differences for the coma no chance scenario, and
cancer with and without pain scenarios (all P<.05).
Post hoc comparisons indicated that for the overall score and for the coma
scenario, primary care physicians made the least overtreatment errors. Hospital-based
physicians made the most overtreatment errors for both cancer scenarios.
Comparing undertreatment errors across surrogate type, significant differences
were found for overall scores (F2,162 = 24.18, P<.001), as well as the Alzheimer disease, emphysema, coma slight
chance, stroke no chance, stroke slight chance, cancer no pain, and cancer
with pain scenarios (all P<.001). Post hoc analyses
indicated that family surrogates made the least undertreatment errors overall.
Primary care physicians made the most undertreatment errors overall, and in
the stroke slight chance and both cancer scenarios. Primary care physicians
made more undertreatment errors than family surrogates in the Alzheimer disease
scenario and both physician groups made more undertreatment errors than the
family surrogates for the remaining 3 scenarios.
ACCURACY OF SURROGATES' PREDICTIONS WITH AND WITHOUT ADs
The second purpose of the present study was to examine whether ADs improved
predictive accuracy for primary care physicians and hospital-based physicians.
Overall accuracy and accuracy in each scenario were compared for decisions
made without the benefit of the patient's AD, with a patient's VLA, and/or
with a patient's HCD. A significant physician type x condition interaction
was found (F2,79 = 3.51, P<.05). Post
hoc tests indicated that for primary care physicians, neither type of AD improved
the accuracy of substituted judgments over not having the patient's AD. However,
for hospital-based physicians, the HCD was effective in improving the accuracy
of decisions compared with not having AD information (Figure 2). As a baseline comparison, family surrogate accuracy scores
by AD condition are indicated in Figure 2 with a dashed line.
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Figure 2. Overall accuracy by surrogate
and advance directive (AD) condition. VLA indicates valued life activities
directive; HCD, health care directive.
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At the level of the individual illness scenarios, a significant interaction
was only found for the coma with no chance scenario (F2,79 = 3.41, P<.05). Like the overall scores, primary care physician
accuracy was not improved by the ADs, although for the hospital-based physicians,
the HCD significantly improved the accuracy of judgments over the no-AD control
condition. Although no other scenario differences achieved statistical significance,
there was a consistent trend for the HCD to improve hospital-based physicians'
accuracy scores over the no-AD and VLA conditions (Table 3).
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Table 3. Proportion of Accurate Predictions, Overtreatment Errors,
and Undertreatment Errors by Hospital-Based Physicians*
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We next compared the types of errors that the physicians made when using
the ADs and with no AD. Overall overtreatment errors by surrogate type can
be seen in Figure 3. (Again, baseline
scores of family surrogates are indicated with a dashed line.) A significant
physician type x condition interaction was found for overall overtreatment
scores (F2,79 = 5.57, P<.01), as well
as for the coma no chance and stroke no chance scenarios (F2,79
= 4.19, P<.05 and F2,79 = 3.33, P<.05, respectively). Post hoc analyses indicated that
when using the HCD, hospital-based physicians made fewer overtreatment errors
than when they were provided with no AD. These findings were consistent across
many of the individual scenarios, although the differences did not achieve
statistical significance (Table 3).
No significant differences were found for primary care physicians. In addition,
no differences were found for the overall undertreatment index by physician
type. Therefore, differences in individual scenarios undertreatment indexes
by physicians were not examined.
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Figure 3. Overtreatment by surrogate and
advance directive (AD) condition. VLA indicates valued life activities directive;
HCD, health care directive.
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Finally, we examined whether ADs had any influence on the confidence
that physicians had in the accuracy of their predictions of patients' preferences
(Figure 4). A significant physician
type x condition interaction was found (F2,79 = 4.36, P<.05). Post hoc comparisons indicated that hospital-based
physicians were more confident in their predictions using either type of AD
compared with no directive. Primary care physicians had no differences in
confidence using either directive compared with no directive.
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Figure 4. Confidence by surrogate and advance
directive (AD) condition. VLA indicates valued life activities directive;
HCD, health care directive.
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COMMENT
Three noteworthy findings are reported in this study. First, without
the benefit of ADs, hospital-based physicians' accuracy when predicting elderly
outpatients' life-sustaining treatment preferences is significantly lower
than that of primary care physicians and family surrogates. Second, although
primary care physicians were significantly less accurate in their decisions
than family surrogates, neither a value-based nor a scenario-based AD helped
to improve the accuracy of their substituted judgments for their patients.
Finally, a scenario-based AD improved the accuracy of hospital-based physicians'
judgments in some scenarios, such that their level of accuracy reached similar
levels of other well-acquainted surrogates.
ACCURACY OF PHYSICIANS' PREDICTIONS OF PATIENTS' PREFERENCES
Consistent with past research, primary care physicians were not highly
accurate in predicting elderly patients' life-sustaining treatment preferences
and frequently predicted that patients would not want treatment when patients
indicated that they would.15, 20, 26
Primary care physicians were most accurate in predictions for scenarios that
can be considered extremes on a continuum of impairment (ie, current health,
coma with no chance of recovery, and terminal cancer with pain). However,
for scenarios between the extremes, where perhaps there may not be an overwhelming
consensus for or against treatment, accuracy was considerably lower.
Although hospital-based physicians often must make life-sustaining treatment
decisions for patients with whom they have no preexisting relationship, little
is known about the accuracy of these decisions compared with patients' recorded
wishes. We found that without ADs, hospital-based physicians have considerable
difficulty making accurate predictions of patient preferences. Unlike primary
care physicians who made undertreatment errors, hospital-based physicians
made more overtreatment errors in their predictions. This may be due to the
default assumption that in an emergency situation everything should be done
to preserve life. Therefore, without explicit directions to withhold treatment,
hospital-based physicians presented with an unfamiliar patient provided life-sustaining
therapies. This may be particularly problematic given that in this study,
hospital-based physicians overtreated in scenarios that involved significant
pain, loss of reasoning abilities, and poor prognoses for recovery—situations
that many patients consider to be "fates worse than death."32
Comparing the 3 types of surrogates (family members, primary care physicians,
hospital-based physicians), our overall results are consistent with those
of others who have found that family surrogates are more accurate than physicians.20, 21 However, a closer examination of
accuracy by type of scenario reveals that primary care physician accuracy
is comparable to that of family surrogates in the extreme situations: current
health, coma with no chance of recovery, and terminal cancer with significant
pain. For these scenarios, primary care physicians were able to predict patient
preferences to the same degree of accuracy as family members who have known
the patient for 40 or more years. However, considering that hospital-based
physicians were also able to achieve high levels of accuracy for the current
health scenario and coma with no chance of recovery scenario without knowing
the specific patients, it may be that primary care physicians were representing
a generalized preference that many members of a community share and not responding
to individual patient preferences. It should be noted that the accuracy for
hospital-based physicians was slightly inflated in the scenario comparisons
with the other surrogates because these means were collapsed across predictions
made with and without the ADs.
Although the finding that hospital-based physicians showed low levels
of accuracy is not surprising, we were surprised to find that hospital-based
physicians without the benefit of ADs were as accurate as the primary care
physicians for many of the scenarios. In addition to the "extreme" scenarios,
hospital-based physicians' accuracy reached comparable levels when imagining
patients who had emphysema or a stroke. It may be that the hospital-based
physicians develop an awareness of what medical treatments most elderly adults
would want due to their direct experience with patients who have these health
impairments, and their experience in making end-of-life decisions. However,
without a direct relationship with the patient, their accuracy is less than
that of family members.
ACCURACY OF SURROGATES' PREDICTIONS OF PATIENTS' PREFERENCES USING
ADs
Ditto and colleagues27 recently reported
that ADs did not help to improve the accuracy of substituted judgment for
decisions made by family members of outpatients. No one has examined whether
ADs can improve the accuracy of substituted judgments made by physicians.
In this study, as in the Ditto et al study,27
we removed many of the confounds of testing ADs in the field. The AD was available
and the physician was engaged in reviewing patients' treatment preferences.
The physicians were instructed to predict the patients' wishes and not indicate
what they would do in a clinical situation. Many physicians openly discussed
differences between what they thought the patient would want and what they
thought they would be inclined to do for the patient in an actual clinical
situation. Despite these highly desirable, controlled conditions, ADs still
did not improve predictive accuracy of primary care physicians.
Advance directives may not aid primary care physicians or family members,
but the results of this study support a role for the documents in a hospital
setting. The HCD improved hospital-based physicians' accuracy consistently
across all but one of the scenarios, although not all of the differences achieved
statistical significance. Decisions made with the VLA also showed this trend,
with improvements in accuracy being seen in 4 of the 9 scenarios. With the
use of ADs, hospital-based physician accuracy was comparable to that of family
members in 4 of the 9 medical scenarios and comparable to primary care physicians'
accuracy in 8 of the 9 scenarios. These results suggest that ADs may be helpful
in an emergency when no family member or physician who knows the patient is
available, for patients who have no next of kin, or for patients whose primary
care physician is not involved in decision making in the hospital.
The HCD, but not the VLA, improved hospital-based physicians' accuracy
by reducing the number of overtreatment errors without also increasing undertreatment
errors. This would indicate that the documents did more than remove the prevailing
bias to "treat" but actually communicated specific preferences to the physicians.
Having either directive increased the hospital-based physicians' confidence
in the accuracy of their decisions. Perhaps the VLA directive was more problematic
because the document contains values that do not translate directly into whether
to use a particular treatment in a given illness scenario.
LIMITATIONS
Several limitations of the present study should be noted. First, it
is possible that the use of hypothetical situations threatens external validity
in real clinical situations because it is unclear whether patients' preferences
and physicians' predictions would be different if faced with an actual illness.
This problem is not unique to this study or to other studies about ADs. Indeed,
the entire practice of AD completion and use in primary care offices, hospitals,
and nursing homes is based on patient preferences for some future hypothetical
illness state.
Another possible limitation was that physicians and patients did not
discuss the patients' preferences while patients completed the ADs. Physicians
were unable to ask patients questions concerning the document or have information
that was written in the document clarified. Although this may be a limitation
of the present study, in a real-life setting most ADs are completed without
physicians and physicians are often unaware that patients have ADs.4 In addition, one study34
reported poor physician understanding of patients' preferences even after
a structured physician-patient discussion.
Finally, the relatively small sample of physicians may limit the present
investigation. The physicians and patients who participated in this study
may not be representative of all primary care practices and may be different
from other practices that did not participate in the ADVANCE project. The
physicians and patients in this study may have had more interest in end-of-life
issues and ADs and so were willing to be involved with the ADVANCE project.
If the participants in the present study were more informed or interested
in ADs, then it could be expected that accuracy would be increased. It could
be argued that this would have created an environment that was optimal for
agreement between patient and physician. If this study were replicated in
other, randomly selected practices, it is possible that that accuracy might
be even lower.
CONCLUSIONS
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