Introduction
Prognostication, along with diagnosis and treatment, is one of the most central issues in palliative care [
1] and is a key factor in decision making for caregivers, patients, and their families in all medical settings. “One of the key roles for palliative care services is to initiate discussions on prognosis and goals of care” [
1]. On the other hand, prognostication in palliative care may be challenged as irrelevant for patients with restricted life expectancy or even as unethical, as communication of a definite and limited time frame may burden the patient.
However, indications of specific treatments, choice of medication, and decisions on care and discharge planning are usually based on a balance of potential burden and benefit of available options [
2]. This balance may shift considerably in relation to the estimated survival time. Estimation of survival time and prognostic uncertainty were named as major factors in decision making on antibiotic treatment in palliative care [
3].
The rationale of the estimations by health care professionals is rarely defined, even though it forms the basis of these important decisions. In a study by Fallowfield et al., 88% of terminally ill patients ask for information about their remaining life span while less than 8% are willing to receive only good or no detailed information [
4]. The question “How long do I have?” addresses patients’ needs and wishes for the residual life span, such as setting up a proxy for decision making, putting financial and social affairs in order, or organizing funeral details [
5].
Communicating prognostic information may raise ethical problems and cause tense dilemmas. It is challenging for physicians to balance between realistic information without increasing anxiety and reducing trust, on one hand, and allowing hope and optimism without creating unrealistic expectations, on the other hand [
6].
Professionals are not generally willing to provide prognostic information and do not feel adequately prepared for this task, even though they are expected to know from their clinical experience. More than half feel poorly trained and report difficulty in formulating and communicating prognosis to patients [
1].
Some studies on prognostication report mean ratios of predicted to observed survival time with a factor of 3–5 [
7], showing overoptimistic estimations of the physicians. Sex, years of medical practice, board certification, cultural background, or self-rated optimism have been investigated as possible bias toward optimism, but no homogenous results could be found [
4,
7].
To improve assessment of prognosis and alleviate communication with terminally ill patients, several workgroups have developed prognostic scoring systems on survival time in palliative care [
1,
8]. To our knowledge, these scores have not been tested in a head-to-head comparison yet. There is also no information whether the prognostic scores can be used in German palliative patients.
This study compared the Palliative Prognostic Index (PPI) and Palliative Prognostic Score (PaP-S) with physicians’ estimation and survival time in palliative care patients in Germany and investigated how appropriate, specific, and sensitive the prognostic scores were in this setting.
Discussion
Discussion of survival time is one of to the most sensitive and ethically challenging issues in palliative care. Patients may be torn between anxiety and fear on one side and hope for survival or a chance to manage their remaining life span despite the worst prognosis on the other side.
Relatives and carers may need accurate information on prognosis, as important decisions may depend on it. As an example from our experience, the son of a patient was asking for the expected time of survival, as he wanted to use his accumulated holiday leave for the time his father died, and was afraid that if he took his leave too soon, he would have to work at the time of his father’s death. Other examples include a visiting relative from Canada asking whether she should reschedule her return flight in 3 weeks time, or a patient asking whether he should cancel the holiday trip planned in 2 months.
Information on prognosis influences the patients’ own conceptions of their future and the ideas on maintaining quality of life for the remaining lifetime as well as their choices in medical technologies and treatments. Patients prefer an “individualized and realistic disclosure from a confident and supportive cancer specialist” [
6] which is understood as hope giving. Physicians, on the other hand, are reluctant to communicate prognosis unless asked and try to be unspecific, but optimistic [
5]. These ideas are slightly contradictory. Additionally, there is a discrepancy between the formulated prognosis (as discussed in the team) and what is communicated to patient and family. However, there can be no doubt that it is the patient’s right to make plans for the residual life span. In consequence, he can also expect a prognosis as precise as possible.
Currently, the estimation of survival at the palliative care units participating in this study depends mostly on “gut feeling” as results of clinical observation and experience of the teams. Patients and their families get information about the prognosis as far as they want to know. However, as shown by the results of this study, estimations of survival times often were incorrect, and most were often too optimistic. This confirms other trials showing overoptimistic prognosis by clinicians. Christakis et al. reported that only 20% of predictions were accurate and 63% overoptimistic by a factor of 5.3 in the physicians’ estimation of survival time [
7]. Similar results are found by Gripp et al. who found 71–96% of estimates of survival on patients who died within 1 month to be overoptimistic [
15].
Christakis et al. observed the effect that a stronger physician–patient relationship is associated with lower prognostic accuracy and that more experienced physicians were more accurate. Considering the conflict between experience and relationship, a trend toward second opinion among colleagues seems meaningful as a more neutral source of opinion without personal investigation into the outcome for the patient [
7].
Prognostic scores would offer additional accuracy for prognostication and thus could facilitate ethical decision making and communication with patient and family. However, even if prognosis scores provide meaningful results for groups of patients with satisfactory specificity and sensitivity, results should be considered carefully for the individual patient, as considerable variation from default is possible.
To our knowledge, available prognostic scores have not been tested in a head-to-head comparison yet. Results from this study show no advantage between PaP-S and PPI. As the PaP-S and the PPI correlate highly in their prognostication, any one of them should be adequate for clinical use in addition to the physicians’ estimation. As both only have a moderate correlation with survival time, clinicians should not rely only on them as the only or main instrument of prognosis. The PPI correlated better with survival time than the PaP-S; however, sensitivity for bad and moderate prognosis was lower than for the PPI.
Physicians’ estimation of survival time reached the lowest correlation with the actual survival. This may be due to the form of this specific question, which was included as an item in the PaP-S. Physicians had to estimate life time in two weekly steps, which seemed to be difficult. The single item on physician estimation correlated closely with both prognostic instruments. This leads to the conclusion that this single item may replace the test. However, the degree of overestimation in the single item and the low correlation with survival time call for additional input for prognostication.
Detailed analysis showed that clinicians were able to score poor or good prognosis more accurately than intermediate prognosis. In line with this finding, the PPI and the PaP-S were as well suited to predict which patients had the poorest survival, but they were less adequate to distinguish between good and intermediate prognosis. This points toward a huge uncertainty with intermediate prognosis. Prognostic assessment tools seem to be most needed for intermediate prognosis. However, in our study, both instruments were not suited for intermediate prognosis.
Regarding the limitations of scoring systems, Henderson et al. tried to establish a best statistical model for prediction which surprisingly included the clinicians’ prediction as an additional risk factor as well, although not accurate [
16].
However, the inclusion of the physicians’ estimate of survival as on the items of the PaP-S seems to produce a dilemma. A prognostic index would be most useful for those occasions where the physician is uncertain of the patient’s survival and relying on a score which give large weighting to the clinicians estimate may be a major drawback [
5]. Following the results of our study, scoring systems on prognosis of survival time seem to be least useful for those patients [
5] with neither a good nor a poor prognosis because here both physicians’ estimates as well as the existing prognostic instruments lack precision.
Physicians’ estimations may have been biased by the format of the item, requiring them to differentiate steps of 2 weeks survival time which demands a very specific estimate. Using broader categories might have resulted in less overestimation. However, clinical practice frequently requires prognostication with this accuracy, for example, if family leave, travel, or holiday schedules or care plans have to be realized.
Limitations of this study are a rather small sample size, and correlations may have been masked by outliers in the restricted sample. However, methodological considerations restricted the number of participating centers and the sample size should have been large enough to demonstrate the usefulness of the scores in clinical practice.
The parallel consideration of the physicians’ estimate as an item of one of the scores (PaP-S), on one hand, and as a comparator for clinical prognostication, on the other hand, may have confounded the evaluation. Using another scale for the physicians’ estimate of survival and not the small-step scoring system of the PaP-S item on the physicians’ estimate could have given more insight into the derivation and determination of their clinical prognostication.
Our results demonstrate the need for more robust and better fitting prognostic tools that can be used in clinical palliative care practice to supplement the clinical estimation of survival. Whereas poor scores in both prognostic scales adequately identified patients with poor prognosis, patients with good scores often did not have longer survival times. Both scores are constructed to differentiate prognostic chances for several weeks. In clinical practice, it would be valuable to have a set of different scores with different time frames. More specifically, a sensitive prognostic score with a shorter time frame, allowing identification of patients in the final days of life, would be helpful for decision making in the terminal phase.
Prognostication with adequate sensitivity and specificity is only the first step in the care of patients with short life expectancy. Not only using prognosis carefully in ethical decision making but also communication strategies with patients and families on prognosis and on the best course of therapy have to supplement prognostication.
Using the available prognostic scores in clinical practice, with due consideration of the shortcomings, will train clinicians in these skills and will facilitate discussion and communication on prognosis.