Doctors Make Inaccurate, but Useful Predictions of Survival for Terminally Ill Patients
“How long do I have to live?” is often the first question patients ask when faced with the diagnosis of advanced disease. In response, doctors face two daunting challenges. They must formulate reasonably correct prognoses and then communicate this information to patients and their loved ones in a way that sounds hopeful but is still accurate. In addition, they need to consider how their patient’s presumed prognosis will affect the judicious use of medical treatments and palliative care. Significant prognostic inaccuracy can have a major impact on the quality of death for patients and their loved ones.
Several studies have suggested that doctors are overly optimistic when predicting the survival of patients with terminal cancer. In a new study published in the July 26, 2003 British Medical Journal (BMJ)—devoted entirely to care of the terminally ill—researchers looked at the diagnosis of dying. After conducting a systematic review, they found that although predictions by doctors correlate with actual survival (and therefore, are clinically useful), doctors consistently overestimate the time patients have left to live. This was especially true the longer patients survived.
About the Study
The researchers analyzed data from eight epidemiologic studies conducted in three countries (the United Kingdom, Italy, and the United States) between 1966 and 2000. All of the studies met the following criteria:
- The study involved patients with terminal cancer
- Outcomes of interest (the results section) included a clinical prediction of survival (CPS) in days or weeks and the duration of patients' actual survival (AS)
- Study authors explained in the methods section how death was determined
Papers that did not include CPS or AS were included in the study if the researchers were able to obtain that information by contacting the authors.
In all, the eight studies covered 1,563 survival predictions.
The researchers found that doctors consistently overestimated CPS; CPS was correct to within one week in 25% of cases, correct to within two weeks in 43% of cases, and correct to within four weeks in 61% of cases. Beyond six months, CPS had no predictive value.
Despite being inaccurate, predictions were seen to be clinically useful because CPS and AS were strongly correlated. That is, even though CPS was incorrect, for predictions of death up to six months, the median actual survival at least was proportional to median predicted survival.
Because of the limited data available, the researchers could not say whether demographics, training, or experience of the doctor made a difference in CPS. Furthermore, since there are no established criteria for reviewing studies of CPS, the ratings used by the researchers to assess the original studies may not be valid.
How Does This Affect You?
This study showed that while doctors have great difficulty predicting when a particular cancer patient is going to die, they do have a sense of when things are going wrong; the nearer the patient is to the date of death, the more accurate is the prediction.
In a related study, researchers from the Netherlands assessed how euthanasia in terminally ill cancer patients affects family and friends. They found that the bereaved family and friends of cancer patients who died by euthanasia coped significantly better than the bereaved of comparable cancer patients who died a natural death—suggesting that knowing the exact time of death eases the transition for the dying patient’s family.
What might be useful, then, is for doctors to consider the possibility that death may be closer than they think. If doctors are better able to predict death, they will be more likely to make judicious use of medical treatments and optimize use of palliative care. Family and friends will also be better prepared for the death of their loved one. All of this, in turn, will help patients to achieve a “good” death.
Glare P, Virik K, Jones M, Eychmuller S, Simes J, Christakas N. A systematic review of physicians’ survival predictions in terminally ill cancer patients. BMJ . 2003;327:195-8.
Swarte NB, van der Lee ML, van der Bom JG, van den Bout J, Heintz APM. Effects of euthanasia on the bereaved family and friends: a cross-sectional study. BMJ . 2003;327:189-92.
Clark, J. Patient centered death. Editorial. BMJ . 2003;327:174-175.
Smith R. Death, come closer. Editorial. BMJ . 2003;327.
Last reviewed July 31, 2003 by
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