Conversion of Karnofsky Performance Status (KPS) and Eastern Cooperative Oncology Group Performance Status (ECOG) to Palliative Performance Scale (PPS), and the interchangeability of PPS and KPS in prognostic tools

The aim of our study was to assess whether the Karnofsky Performance Status (KPS), the Eastern Cooperative Oncology Group (ECOG) Performance Status, and the Palliative Performance Scale (PPS) are interchangeable individually or within two prognostic tools: the Palliative Prognostic Score (PaP) and the Palliative Prognostic Index (PPI). We performed a subset analysis of a prospective comparative study of functional and prognostic tools and clinician prediction of survival. We studied 955 patients with advanced life-limiting illnesses (cancer and noncancer) in the acute care and community settings. We used a descriptive statistical model and Spearman's rank correlation to assess these interchangeabilities. There is a direct positive linear relationship between the KPS and the PPS, and a direct negative linear relationship between these tools and the ECOG. Exchange of the KPS and the PPS was possible within the PaP and the PPI. The PPS and the KPS can be used interchangeably as functional tools and within prognostic tools. The ECOG is interchangeable with the PPS and the KPS, but this interchangeability is population-specific.