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Nicholas A Christakis a Department of Medicine, University of Chicago
Medical Center, Chicago, IL 60637, USA, b Robert Wood Johnson Clinical
Scholars Program, University of Chicago Medical Center
Correspondence to:
N A Christakis nchrista{at}medicine.bsd.uchicago.edu
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Abstract |
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Objective:
To describe doctors' prognostic accuracy
in terminally ill patients and to evaluate the determinants of that accuracy.
Although doctors commonly have to prognosticate, most feel
uncomfortable doing so.1 Neither medical
training
1 2
nor published literature
3 4
treat prognostication as important, and prognostic error is
widespread.2 Unfortunately, prognostic error may have
untoward effects on both patient care and social policy.
Parkes showed that doctors' predictions of survival in 168 cancer
patients were often erroneous and optimistic,5 and these findings were confirmed by subsequent studies.6-10
However, previous work has been limited by use of small samples of
patients and very small samples of prognosticators (typically fewer
than four); failure to examine whether certain types of doctors are
more likely to err in certain types of patients; and neglect of the
possibility of different determinants of optimistic and pessimistic
error. Therefore, we conducted a large, prospective cohort study of
terminally ill patients to evaluate the extent and determinants of
prognostic error.
Our cohort consisted of all patients admitted to five outpatient
hospice programmes in Chicago during 130 consecutive days in 1996. Participating hospices notified us about patients on admission, and we
immediately contacted the referring doctors to administer a four minute
telephone survey. Of the 767 patients (referred by 502 doctors), 65 did
not meet the entry criteria (they were children, were denied hospice
admission, or refused to give consent) and 51 died before we were
notified (and thus survival predictions would be meaningless). Of the
remaining 651 patients, for 66 (10%) we contacted the doctor only
after the patient's death (and so could not get meaningful prognoses),
for 14 (2%) the doctor refused to participate, and for 67 (10%) the doctor could not be contacted. We thus completed surveys with 365 different doctors caring for 504 patients (504/651=77%). Comparison of
these 504 patients with the 147 excluded patients showed no important
differences in patient or doctor characteristics. On 30 June 1999 we
had dates of death for 486 of the 504 patients (96%). Because data
were occasionally missing, not all totals in the analyses are equivalent.
We obtained the patients' age, sex, race, religion, marital status,
diagnosis, and comorbidities from the hospice. From the survey, we
obtained an estimate of how long the patient had to live; information
about the patient, including Eastern Cooperative Oncology Group
performance status11 and duration of illness; information
about the doctor, including experience with similar patients and self
rated dispositional optimism; and information about the doctor-patient
relationship, including the duration, recentness, and frequency of
contact. We obtained other data on the doctors, such as specialty,
years in practice, and board certification from public records. Dates
of patients' deaths were obtained from public death registries or the hospices.
We divided the observed by the predicted survival, and deemed prognoses
"accurate" if this quotient was between 0.67 and 1.33. Values less
than 0.67 were "optimistic" prognostic errors and those greater
than 1.33 were "pessimistic." We conducted analyses using different
cut off points or more categories, as well as analyses that treated
this quotient as a continuous measure, but these analyses did not
contravene the results presented. To evaluate associations between
categorical and continuous variables and the trichotomous prognostic
accuracy variable, we used The patients had a mean age of 69 (SD 17) years and 225/504 (45%)
were men. The diagnosis was cancer in 326 (65%), AIDS in 62 (12%),
and other conditions in 116 (23%). The mean duration of disease was
83.5 (135.8) weeks, and the median performance status was 3 (corresponding to >50% of the day spent bedridden). The doctors had a
median duration of medical practice of 16 years; 291/363 (80%) were
men; 293/365 (80%) were board certified; and 255/345 (74%) rated
themselves optimistic. A total of 114/358 (32%) specialised in general
internal medicine, 71/358 (20%) in non-oncological internal medicine
subspecialties, 61/358 (17%) in oncology, 55/358 (15%) in family or
general practice, 27/358 (8%) in geriatrics, and 30/358 (8%) were
surgeons or practised other specialties. In the past year, the doctors
had had experience caring for a median of five patients with the same
diagnosis and had referred a median of eight patients to a hospice.
They had known the patient an average of 159 (308) weeks; had 11 (14)
contacts in the previous three months; and had examined the patient 14 (29) days before.
Doctors' prognostic estimates
Design:
Prospective cohort study.
Setting:
Five outpatient hospice programmes in Chicago.
Participants:
343 doctors provided survival estimates
for 468 terminally ill patients at the time of hospice referral.
Main outcome measures:
Patients' estimated and actual survival.
Results:
Median survival was 24 days. Only 20%
(92/468) of predictions were accurate (within 33% of actual survival); 63% (295/468) were overoptimistic and 17% (81/468) were
overpessimistic. Overall, doctors overestimated survival by a factor of
5.3. Few patient or doctor characteristics were associated with
prognostic accuracy. Male patients were 58% less likely to have
overpessimistic predictions. Non-oncology medical specialists were
326% more likely than general internists to make overpessimistic
predictions. Doctors in the upper quartile of practice
experience were the most accurate. As duration of doctor-patient
relationship increased and time since last contact decreased,
prognostic accuracy decreased.
Conclusion:
Doctors are inaccurate in their prognoses for terminally ill patients and the error is systematically optimistic. The inaccuracy is, in general, not restricted to certain kinds of
doctors or patients. These phenomena may be adversely affecting the
quality of care given to patients near the end of life.
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Introduction
Top
Abstract
Introduction
Participants and methods
Results
Discussion
References
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Participants and methods
Top
Abstract
Introduction
Participants and methods
Results
Discussion
References
2 tests and analysis of
variance respectively. We used multinomial logistic regression to
assess the multivariate effect of patient and doctor variables on
prognostic accuracy.
![]()
Results
Top
Abstract
Introduction
Participants and methods
Results
Discussion
References
In only 18 of 504 patients did the doctor refuse to predict
survival to us. Eighteen of the remaining 486 had missing dates of
death, leaving 468 cases referred by 343 doctors for analysis of
prognostic accuracy. The figure illustrates the extent of the error.
The median observed patient survival was 24 days. The mean ratio of
predicted to observed survival was 5.3. The correlation between
predicted and observed survival was 0.28 (P<0.01). When an accurate
prediction was defined as between 0.67 and 1.33 times the actual
survival, 20% (92/468) of predictions were accurate, 63% (295/468)
optimistic, and 17% (81/468) pessimistic. When an accurate prediction
was defined as between 0.50 and 2.0 times the actual survival, 34%
(159/468) of predictions were accurate, 55% (256/468) optimistic, and
11% (53/468) pessimistic. Death occurred within one month of the
predicted date for 42% (195/468) of patients, at least one month
before the predicted date in 46% (214/468), and at least one month
after the predicted date in 13% (59/468) of
patients.

View larger version (35K):
[in a new window]
Predicted versus observed survival in 468 terminally ill hospice
patients. Diagonal line represents perfect prediction. Patients above
diagonal are those in whom survival was overestimated; patients below
line are those in whom survival was underestimated
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Factors associated with prognostic accuracy
Bivariate analyses of the trichotomous accuracy variable and
patient attributes showed no important differences with respect to
patients' age, sex, race, religion, or marital status. However, cancer
patients were the most likely to have overoptimistic predictions
(220/301 (67%) v 37/58 (64%) of AIDS patients and
56/109 (51%) of other patients) and the least likely to have
overpessimistic predictions (39/301 (13%) v 13/58
(22%) and 29/109 (27%)); AIDS patients were the least likely to have correct predictions (8/58 (14%) v 60/301 (20%) of
cancer patients and 24/109 (22%) of others; P<0.01).
for example, each one year longer that
the doctor had known the patient resulted in a 12% increase in the
odds of an overpessimistic prediction (1.12; 1.02 to 1.22). Also, as
the interval since last physical examination increased, the odds of a
doctor making a pessimistic rather than a correct prediction decreased;
each day longer resulted in a 3% decrease in the odds (0.97; 0.94 to
0.99).
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Discussion |
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Our study of 365 doctors and 504 hospice outpatients found that
only 20% of prognoses were accurate. Most predictions (63%) were
overestimates, and doctors overall overestimated survival by a factor
of about five. These prognoses were doctors' best guesses about their
patients' survival prospects, objectively communicated to the
investigators and not to patients themselves. Close multivariate
examination showed that most doctor and patient attributes were not
associated with prognostic error. However, the tendency of doctors to
make prognostic errors was lower among experienced doctors. Moreover,
the better the doctor knew the patient
as measured, for example, by
the length and recentness of their contact
the more likely the doctor
was to err.
These findings have several implications. Firstly, undue optimism about survival prospects may contribute to late referral for hospice care, with negative implications for patients. 12 13 Indeed, although doctors state that patients should ideally receive hospice care for three months before death,14 patients typically receive only one month of such care.15 The fact that doctors have unduly optimistic ideas about how long patients have to live may partly explain this discrepancy. Doctors who do not realise how little time is left may miss the chance to devote more of it to improving the quality of patients' remaining life. Secondly, to the extent that doctors' implicit or explicit communication of prognostic information affects patients' own conceptions of their future, doctors may contribute to patients making choices that are counterproductive. Indeed, one study found that terminally ill cancer patients who hold unduly optimistic assessments of their survival prospects often request futile, aggressive care rather than perhaps more beneficial palliative care.16 Thirdly, our work hints at corrective techniques that might be used to counteract prognostic error. Disinterested doctors, with less contact with the patient, may give more accurate prognoses, perhaps because they have less personal investment in the outcome.17 Clinicians may therefore wish to seek "second opinions" regarding prognoses, and our work suggests that experienced doctors may be a particularly good source of opinion. Finally, our work suggests that prognostic error in terminally ill patients is rather uniformly distributed. This has implications for doctors' training and self assessment since it suggests that there is not one type of doctor who is prone to error, nor is there one type of patient in whom doctors are likely to err.
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What is already known on this topic
Doctors' prognostic estimates are a central element of both patient and physician decision making, especially at the end of life Doctors' prognostic estimates in their terminally ill patients are often wrong and usually optimistic What this study addsA prospective cohort study of 504 terminally ill patients and their 365 doctors found that only 20% of the doctors' predictions were accurate: 63% were overoptimistic and 17% overpessimistic Multivariate modelling showed that most types of doctors are prone to error, in most types of patients The greater the experience of the doctor the greater the prognostic accuracy, but a stronger doctor-patient relationship is associated with lower prognostic accuracy |
Obtaining prognostic information is often the highest priority for
seriously ill patients, eclipsing their interest in treatment options
or diagnostic details.
18 19
And reliable prognostic information is a key determinant of both doctors' and patients' decision making.
16 20 21
Although some error is
unavoidable in prognostication, the type of systematic bias towards
optimism that we have found in doctors' objective prognostic
assessments may be adversely affecting patient care.
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Acknowledgments |
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We thank Elena Linden and Tammy Polonsky for help in administering the survey.
Contributors: NAC initiated the study, conceptualised the key questions, oversaw data collection, assisted in data analysis, and cowrote the paper. EBL conceptualised the key questions, performed most of the data analysis, and cowrote the paper. Both authors will act as guarantors.
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Footnotes |
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Funding: Soros Foundation Project on Death in America Faculty Scholars Program (NAC), the American Medical association Education and Research Foundation (NAC), and the Robert Wood Johnson Clinical Scholars Program (EBL).
Competing interests: Both authors have occasionally received honorariums for speaking at events sponsored by hospices.
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References |
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Christakis NA, Iwashyna TJ.
Attitude and self-reported practice regarding prognostication in a national sample of internists.
Arch Intern Med
1998;
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2389-2395 |
| 2. | Christakis NA. Death foretold: prophecy and prognosis in medical care. Chicago, IL: University of Chicago Press, 1999. |
| 3. | Christakis NA. The ellipsis of prognosis in modern medical thought. Soc Sci Med 1997; 44: 301-305. |
| 4. | Fletcher SW, Fletcher RH, Greganti MA. Clinical research trends in general medical journals, 1946-1976. In: Roberts EB, Levy RI, Finkelstein SN, Moskowitz J, Sondik EJ, eds. Biomedical innovation. Cambridge: MIT Press, 1981. |
| 5. | Parkes CM. Accuracy of predictions of survival in later stages of cancer. BMJ 1972; ii: 29-31. |
| 6. | Heyse-Moore LH, Johnson-Bell VE. Can doctors accurately predict the life expectancy of patients with terminal cancer? Palliat Med 1987; 1: 165-166. |
| 7. | Addington-Hall JM, MacDonald LD, Anderson HR. Can the Spitzer quality of life index help to reduce prognostic uncertainty in terminal care? Br J Cancer 1990; 62: 695-699[Medline]. |
| 8. | Mackillop WJ, Quirt CF. Measuring the accuracy of prognostic judgments in oncology. J Clin Epidemiol 1997; 50: 21-29[CrossRef][Medline]. |
| 9. | Forster LE, Lynn J. Predicting life span for applicants to inpatient hospice. Arch Intern Med 1988; 148: 2540-2543[Abstract]. |
| 10. | Evans C, McCarthy M. Prognostic uncertainty in terminal care: can the Karnofsky index help? Lancet 1985; 1: 1204-1206[CrossRef][Medline]. |
| 11. | Zubrod GC, Schneiderman M, Frei E, Brindley C, Gold GL, Shnider B, et al. Appraisal of methods for the study of chemotherapy of cancer in man: comparative therapeutic trial of nitrogen mustard and triethylene thiophosphoramide. J Chron Dis 1960; 11: 7-33[CrossRef]. |
| 12. | Pearlman RA. Inaccurate predictions of life expectancy: dilemmas and opportunities. Arch Intern Med 1988; 148: 2537-2538[CrossRef][Medline]. |
| 13. | Lynn J, Teno JM, Harrell FM. Accurate prognostication of death: opportunities and challenges for clinicians. West J Med 1995; 163: 250-257[Medline]. |
| 14. | Iwashyna TJ, Christakis NA. Attitude and self-reported practice regarding hospice referral in a national sample of internists. Palliat Med 1998; 1: 241-248. |
| 15. |
Christakis NA, Escarce JJ.
Survival of Medicare patients after enrolment in hospice programs.
N Engl J Med
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335:
172-178 |
| 16. |
Weeks JC, Cook EF, O'Day SJ, Peterson LM, Wneger N, Reding D, et al.
Relationship between cancer patients' predictions of prognosis and their treatment preferences.
JAMA
1998;
279:
1709-1714 |
| 17. | Poses RM, McClish DK, Bekes C, Scott WE, Morley JN. Ego bias, reverse ego bias, and physicians' prognostic judgments for critically ill patients. Crit Care Med 1991; 19: 1533-1539[Medline]. |
| 18. | Degner LF, Kristjanson LJ, Bowman D, Sloan JA, Carriere K, O'Neil J, et al. Information needs and decisional preferences in women with breast cancer. JAMA 1997; 277: 1485-1492[Abstract]. |
| 19. | Blanchard CG, Labrecque MS, Ruckdeschel JC, Blanchard EB. Information and decision-making preferences of hospitalized adult cancer patients. Soc Sci Med 1988; 27: 1139-1145. |
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Murphy DJ, Burrows D, Santilli S, Kemp AW, Tenner S, Kreling B, et al.
The influence of the probability of survival on patients' preferences regarding cardiopulmonary resuscitation.
N Engl J Med
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330:
545-549 |
| 21. | Frankl D, Oye RK, Bellamy PE. Attitudes of hospitalized patients toward life support: a survey of 200 medical inpatients. Am J Med 1989; 86: 645-648. |
(Accepted 5 November 1999)
Julia L Smith Hospice of Rochester, Rochester,
NY 14607, USA
julia.smith{at}viahealth.org
American doctors refer patients to hospice too late.
Christakis and Lamont's research shows that doctors are poor
prognosticians and tend to overestimate how long a person who is
terminally ill will live.
Most of the patients in their study had cancer (65%). This is a
similar proportion to that found in hospice patients in a survey
carried out in 1995 (60%), despite the fact that cancer is not the
leading cause of death in the United States. Seven per cent of the
patients referred to these hospices died within hours of admission.
This eleventh hour referral pattern is at least partly due to doctors
not recognising the nearness of death.
A patient is eligible for hospice care if they have an estimated life
expectancy of six months or less. As the authors point out, the actual
length of stay is usually less than six weeks. Thus most patients come
to hospice during a period of rapid physical change and often in
crisis. And they don't live long beyond the crisis.
At times of crisis, the immediate management of symptoms and relieving
the family overshadows the need to address the emotional and spiritual
issues of remembering, forgiving, and bringing to closure the issues of
a person's life. Provision of a physically comfortable death is a
worthy goal. It reduces regrets among survivors. Yet more time provides
the opportunity for the dying person to participate directly in the
process of validating the past and planning for the future and gives
the family the chance to relish or repair bonds with the dying person.
The National Hospice Organisation has tried to educate doctors on how
to predict appropriate entry points to hospice for various
conditions.1 These guidelines should be incorporated into
the general education of doctors.
The authors' suggestion that prognostication should be done by a
"disinterested" experienced doctor hits near one common thread of
late hospice referrals. Doctors may be reluctant to acknowledge that
patients they know well are close to death. This can be compounded by
the patient's and family's preference to keep hoping for the patient
to live longer. Those of us who know our patients longer often become
attached to them. We, too, hate to admit that death is near. I remember
a woman in her 60s I was treating for metastatic breast cancer. She was
admitted to the hospital with gastric bleeding that was thought to be
unrelated to her cancer. I remember talking to her and her husband and
being optimistic about the reversibility of the problem. Because I was
trying not to scare her I did not discuss the issues of advanced
directives and resuscitation. That night she went into shock, required
intubation, and went to the intensive care unit. Her husband was
devastated and angry that she had had such treatment. The next day he
and I together decided that no additional treatment would be given to
prevent her death. He sat with her for over 24 hours before she died.
My desire to be optimistic prolonged her dying and added anguish to her
husband. Doctors often rail against the denial of patients and their
families. Yet we are not immune.
Decisions at the end of life are not just guided by doctors. There is a
complex interaction of doctor recognising and acting on accurate
prognostication, what the doctor tells the patient and family, and what
the patient and family actually hear. Christakis and Lamont have begun
to help tease out the factors involved in end of life predictions. In
oncology, the end of chemotherapy usually signals the terminal phase.
In other specialties, prognosis is much less demarcated. Doctors should
better define landmarks or turning points in prognosis and begin to
acknowledge these to ourselves and to our patients. Only then can we
adequately guide our patients through the dying process.
Competing interests: None declared.
Colin Murray Parkes Chorleywood, Hertfordshire WD3 5AS
cmparkes{at}aol.com
The accurate prediction of survival is important for
several reasons. Excessive optimism may cause us to wait too long to refer people for palliative care, we may delay the use of narcotic drugs for pain relief, and we may persist in unpleasant and pointless treatments aimed at curing or prolonging life when it would be kinder
to stop.
This being the case, it is disappointing to learn from Christakis and
Lamont that doctors are still no better at predicting the length of
survival of our terminally ill patients than they were 27 years
ago.1 Experienced oncologists may be slightly less starry
eyed than the rest of us, but even they are overoptimistic about the
likely length of survival of their patients. If all predictions had
been divided by two they would have been marginally more accurate.
This failure has to be set against the recent success of research
instruments such as Morita's palliative prognostic
index2-4 and Maltoni's palliative prognostic
score,5-6 both of which have been shown to predict short
term survival reasonably well. These short and simple instruments make
use of a mixture of performance measures and systematic symptom
assessments rather than relying on intuition and clinical judgment alone.
In the long term it may be possible to extract from the
research those criteria that will enable us to make more reliable clinical predictions. Until that time arrives we would do better to stop guessing and, when predictions are needed, to make use of these indices.
Competing interests: None declared.
website extra: A table showing the results of regression
analysis is available on the BMJ's website. www.bmj.com
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References
1.
Stuart B, Alexander C, Arenella C.
Medical guidelines for determining prognosis in selected non-cancer diseases.
2nd ed.
Arlington, VA: National Hospice Organization, 1996.
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Footnotes
Commentary: Prognoses should be based on proved
indices not intuition
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References
1.
Parkes CM.
Accuracy of predictions of survival in later stages of cancer.
BMJ
1972;
ii:
29-31.
2.
Morita T, Tsunoda J, Inoue S, Chihara S, Ishimoto O, Hisaoka N, et al.
Prediction of survival of terminally ill cancer patients
a prospective study.
Jap J Cancer Chemother
1998;
25:
1203-1211.
3.
Morita T, Tsunoda J, Inoue S, Chihara S.
The palliative prognostic index: a scoring system for survival prediction of terminally ill cancer patients.
Supportive Care in Cancer
1999;
7:
128-133[CrossRef][Medline].
4.
Morita T, Tsunoda J, Inoue S, Chihara S.
Survival prediction of terminally ill cancer patients by clinical symptoms: development of a simple indicator.
Jap J Clin Oncol
1999;
29:
156-159 5.
Maltoni M, Nanni O, Pirovano M, Scarpi E, Indelli M, Martini C, et al.
J Pain Symptom Manage
1999;
7:
240-247.
6.
Pirovano M, Maltoni M, Nanni O, Marinari M, Indelli M, Zaninetta G, et al.
A new palliative prognostic score: a first step for the staging of terminally ill cancer patients.
J Pain Symptom Manage
1999;
17:
231-239[CrossRef][Medline].
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Footnotes
© BMJ 2000
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