Integrated Models

Integrated models combine clinical predictors together through analytically determined weights to yield a single patient score that can be mapped to an expected survival.

For example, Morita and colleagues developed the Palliative Prognostic Index (PPI) through creating a regression model that predicted patient survival from performance status and certain clinical signs and symptoms among a sample of 150 patients enrolled in palliative care programs. They then tested the approach on a second sample of 95 patients, finding that the PPI predicted 3-week survival with sensitivity of 83% and a specificity of 85% and 6-week survival with sensitivity of 79% and a specificity of 77%. The table below contains a description of the PPI scoring system and the following table , a summary of predictive relevance of PPI scores.

Description of the Components of the Palliative Prognostic Index: a Scoring System for Survival Predication of Terminally Ill Cancer Patients

Prognostic domains

Partial score value

Performance status
10-20 4.0
30-50 2.5
(Epsilon)60 0
Clinical symptoms

Oral intake

Moderately reduced

1.0

Severely reduced

2.5

Normal

0
Edema 1.0
Dyspnea at rest 3.5
Delirium 4.0
The scores from each prognostic domain are added, and the sum total is associated with a likelihood of survival as described in the next table: Median Survival of Patients According to Palliative Prognostic Index Score.

Morita T, Tsundoa J, Inoue S, et al. The Palliative Prognostic Index: a scoring system for survival prediction of terminally ill cancer patients. Support Care Cancer 1999;7:128-133.

Several other groups have developed similar scoring systems that rely on integration of all or some of the previously described classes of prognostic indicators of patients with advanced cancer and under palliative care (Shimozuma 2000, Tamburini 1996, Maltoni 1999). Such scoring systems need to be sensitive to a variety of methodological concerns including whether or not they are applicable to patients different from the population in whom it was developed and validated (e.g., patients not yet enrolled in palliative care programs)

 

Median Survival of Patients According to Palliative Prognostic Index Scorea.

Palliative Prognostic Index score

Median survival (d)

0.0-2.0 90
2.1-4.0 61
>4.0 12
a Median survival value was estimated from survival curve in paper.

From Morita T, Tsundoa J, Inoue S, et al. The Palliative Prognostic Index: a scoring system for survival prediction of terminally ill cancer patients. Support Care Cancer 1999;7:128-133.

 

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