Palliative prognostic index in end-of-life cancer care: A comparative study of different cut-off scores.

Abstract

258 Background: Accurate prognostication of survival in terminally ill cancer patients, particularly those with a life expectancy of less than three weeks, is critical to palliative care. It facilitates tailored care and enhances communication with patients and their families. The Palliative Prognostic Index (PPI) is a commonly used approach. However, a comprehensive examination of PPI's utility and predictive accuracy remains largely unexplored, particularly at different cut-off scores, compared to other prognostic tests. This study aims to determine and compare the predictive utility of PPI (at cut-off scores >4, >5, and >6) in estimating survival of less than three weeks in terminally ill cancer patients. Methods: A systematic search of MEDLINE, Embase, and Cochrane databases was conducted until November 2022, focusing on studies evaluating the predictive utility of PPI and other prognostic tests for cancer patients with a survival prognosis of less than three weeks. Statistical analyses were carried out using R software (version 4.0.3) and the mada package, enabling the aggregation of sensitivity, specificity, false-positive rate estimates, diagnostic odds ratio, and both positive and negative Likelihood Ratios (LRs). All outcomes are reported with a 95% Confidence Interval (CI) and I2 statistic to measure heterogeneity among the studies. Results: The meta-analysis included 16 studies with 9,839 patients. At a PPI cut-off score >4, the pooled sensitivity was 83.3% (95% CI: 79.6-86.5%, I2=78.1%), specificity was 58.5% (95% CI: 52.4-64.4%, I2=83.6%), false-positive rate was 41.5% (95% CI: 35.6-47.6%), diagnostic odds ratio was 7.04 (95% CI: 4.95-9.98), positive LR was 2.01 (95% CI: 1.73-2.34), and negative LR was 0.29 (95% CI: 0.23-0.36). At a PPI cut-off score >5, the pooled sensitivity decreased to 65.9% (95% CI: 54-76%, I2=96.2%), but specificity increased to 70.2% (95% CI: 57-80.7%, I2=97.3%), false-positive rate was 29.8% (95% CI: 19.3-43%), diagnostic odds ratio was 4.54 (95% CI: 2.13-9.71), positive LR was 2.21 (95% CI: 1.43-3.42), and negative LR was 0.49 (95% CI: 0.34-0.70). At a PPI cut-off score >6, the pooled sensitivity was 68.6% (95% CI: 58.4-77.2%, I2=95%), specificity increased further to 79% (95% CI: 72.1-84.6%, I2=95.1%), false-positive rate was 21% (95% CI: 15.4-27.9%), diagnostic odds ratio was 8.24 (95% CI: 4.61-14.71), positive LR was 3.27 (95% CI: 2.36-4.55), and negative LR was 0.39 (95% CI: 0.29-0.54). Conclusions: This study evaluated the predictive utility of varying Palliative Prognostic Index (PPI) cut-off scores for short-term survival in terminally ill cancer patients, suggesting a higher cut-off score (>6) optimizes specificity and reduces false positives. Our findings offer practical insights for healthcare providers in tailoring PPI score selection and underscore the need for further research in diverse settings and populations.