A Systematic Review of Predictions of Survival in Palliative Care: How Accurate Are Clinicians and Who Are the Experts?

Abstract

Background: Prognostic accuracy in palliative care is valued by patients, carers, and healthcare professionals. Previous reviews suggest clinicians are inaccurate at survival estimates, but have only reported the accuracy of estimates on patients with a cancer diagnosis.

Objectives: To examine the accuracy of clinicians' estimates of survival and to determine if any clinical profession is better at doing so than another.

Data sources: MEDLINE, Embase, CINAHL, and the Cochrane Database of Systematic Reviews and Trials. All databases were searched from the start of the database up to June 2015. Reference lists of eligible articles were also checked.

Inclusion criteria: patients over 18, palliative population and setting, quantifiable estimate based on real patients, full publication written in English.

Exclusion criteria: if the estimate was following an intervention, such as surgery, or the patient was artificially ventilated or in intensive care.

Study appraisal and synthesis methods: A quality assessment was completed with the QUIPS tool. Data on the reported accuracy of estimates and information about the clinicians were extracted. Studies were grouped by type of estimate: categorical (the clinician had a predetermined list of outcomes to choose from), continuous (open-ended estimate), or probabilistic (likelihood of surviving a particular time frame).

Results: 4,642 records were identified; 42 studies fully met the review criteria. Wide variation was shown with categorical estimates (range 23% to 78%) and continuous estimates ranged between an underestimate of 86 days to an overestimate of 93 days. The four papers which used probabilistic estimates tended to show greater accuracy (c-statistics of 0.74-0.78). Information available about the clinicians providing the estimates was limited. Overall, there was no clear "expert" subgroup of clinicians identified.

Limitations: High heterogeneity limited the analyses possible and prevented an overall accuracy being reported. Data were extracted using a standardised tool, by one reviewer, which could have introduced bias. Devising search terms for prognostic studies is challenging. Every attempt was made to devise search terms that were sufficiently sensitive to detect all prognostic studies; however, it remains possible that some studies were not identified.

Conclusion: Studies of prognostic accuracy in palliative care are heterogeneous, but the evidence suggests that clinicians' predictions are frequently inaccurate. No sub-group of clinicians was consistently shown to be more accurate than any other.

Implications of key findings: Further research is needed to understand how clinical predictions are formulated and how their accuracy can be improved.

Fig 1. PRISMA study flowchart.

Fig 2. Summary data from studies in which clinicians provided categorical survival estimates (grouped by number of categories).

The data represented is the percentage of accurate estimates given out of the total number of estimates given. Note: The study by Gwilliam et al (2013) included doctor, nurse and MDT estimates. However, since the estimates were not independent of each other, only the MDT estimates have been presented here.

Fig 3. Professional Error Score (PES) of clinicians’ estimates of survival those studies where clinicians were asked to provide a continuous temporal estimate of survival.

The black bar in this figure indicates the overall accuracy of the clinicians’ estimates (0 indicates perfect accuracy, positive values indicate over-estimates and negative values indicate under-estimates).