Revisiting the Palliative Performance Scale: change in scores during disease trajectory predicts survival.

Abstract

The Palliative Performance Scale (PPS) on admission is a predictor of survival. However, it is not highly discriminating for mid-range scores. 'PPS Change' between two time points considers the disease trajectory, and may improve the scale's utility. The aim of this study is to determine if a change in PPS scores between two significant time points predicts survival. This prospective cohort study examined 'Change on Admission', 'Change at Week 1', and 'Change at Week 2'. We followed patients until death or 6 months, whichever was earlier. Cox regressions were used to determine if the Change scores were predictors of survival, adjusting for age, sex, diagnosis category, Charlson Index, and Do-Not-Resuscitate order. The sample consisted of patients referred to the palliative care service. All three Change scores were independent predictors of survival. The greater the change, the poorer the prognosis. At week 1, when compared to 'PPS Change ≤ 10%', 'Change 11% -30%' and 'Change > 30%' increased the hazard ratios by 1.70 (95% CI 1.10-2.63) and 3.14 (95% CI 1.77-5.59), respectively. At week 2, when compared to 'PPS Change ≤ 10%', 'Change 11% -30%' and 'Change > 30%' increased the hazard ratios by almost 3- and 8-fold, respectively. The same magnitude of Change scores also has higher hazard ratios as patients' hospitalization progressed. The magnitude of change in PPS score during the disease trajectory is associated with one's survival and is a potentially useful prognostication tool. Further research is needed to extend on our work.