This retrospective observational study was conducted on patients consecutively admitted to the hospice center of Yuebei People’s Hospital sponsored by the Li Ka Shing Foundation between January 2014 and December 2018. In this study, patients who satisfied the following criteria were included: (1) at least 18 years old; (2) must be diagnosed with locally extensive or metastatic advanced cancer in a ‘‘high-level hospital’’, including hematological neoplasm; (3) agree to participate in palliative home care service. Patients who terminated the services halfway or data missing were excluded. Patients’ demographic information (age, gender, site of primary cancer and metastatic disease and survival time) and clinical characteristics (performance status, symptoms, and signs) were assessed and recorded by a palliative care team, consisting of 2 physicians, 2 specialist nurses, and 1 social worker at the first consultation. All patients were followed up by home visits or phone calls on a regular basis until the end of the service when patients passed away. The calculation of the survival time was from the date of the first assessment until the date of death. The study was approved by the ethical review board of Yuebei People's Hospital Affiliated to Shantou University Medical College (SUMC-IRB-2019). Informed consent was waived because of the retrospective nature of the study.
Chinese Prognosis Scale
The ChPS was initially developed by Zhou et al. in 2009 to predict the survival of advanced cancer patients in the HPC setting. The ChPS score was calculated by summing the scores of ten prognostic factors: weight loss, nausea, dysphagia, dyspnea, edema, cachexia, dehydration, gender, KPS (Karnofsky Performance Status) scores, and QOL (Quality of Life) scores.  The range of ChPS scores is from 0 (no altered variables) to 124 (maximal altered variables). Patients were classified into 2 risk groups according to the original article: group A included patients with ChPS scores ≤28 and group B with ChPS scores >28. A ChPS score of more than 28 predicts survival of less than 90 days, and a score of less than or equal to 28 predicts survival of 90 to 180 days.
Palliative Prognostic Index
The PPI was initially developed by Morita et al. in 1999 to predict the survival of advanced cancer patients in palliative care units. The PPI score was calculated by summing the scores of five independently predictive variables: PPS scores, oral intake, edema, dyspnea at rest, and delirium. The PPS scores in the present study were transferred from the KPS scores. KPS scores of 10-100 corresponded to PPS scores of 10-100, respectively. The range of PPI scores is from 0 to 15. Patients were classified into 3 risk groups according to the original article: group A (0.0- 4.0), group B (4.1-6.0), and group C (6.1-15.0). Patients with a PPI score of more than 6 survive less than 21 days, and with a score of more than 4 survive less than 42 days.
Performance Status–Based Palliative Prognostic Index
Using the Eastern Cooperative Oncology Group (ECOG) PS to assess advanced cancer patients’ performance status instead of the Palliative Performance Scale (PPS), the PS-PPI was recently developed by Takeshi et al. in 2016 to predict the survival of advanced cancer patients. The PS-PPI score was calculated by summing the scores of the ECOG PS scores, oral intake, delirium, dyspnea at rest, and edema. The ECOG PS scores in the present study were transferred from the KPS scores. KPS scores of 100, 90-80, 70-60, 50-40, and 30-10 corresponded to ECOG PS scores of 0, 1, 2, 3, and 4, respectively. The range of PS-PPI scores is from 0 to 15. Patients were classified into 3 risk groups according to the original article: group A (0.0- 4.0), group B (4.1-6.0), and group C (6.1-15.0). A PS-PPI score of more than 6 predicts survival of less than 21 days, and a score of more than 4 predicts survival of less than 42 days.
General characteristics of patients and variables of the three prognostic tools were summarized and analyzed. Survival curves were estimated using the Kaplan-Meier method, and the log-rank test was used to compare survival times among each risk group of these three prognostic tools. The area under the receiver operating characteristic curve (AUROC) was calculated to determine the accuracy of the three prognostic tools for predicting survival time within 7, 14, 21, 30, 42, 60, 90, 120, 150, and 180 days. The AUROC of the PPI, PS-PPI and ChPS were compared respectively based on the DeLong method. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and overall accuracy (OA) were calculated for prediction of 21-day, 42-day, and 90-day survival using the best cutoff score, which was decided by Youden index. In all analyses, P <0.05 was defined as significance. Survival time was presented as median (95% CI, confidence intervals), and continuous data was presented as mean (SD, standard deviation). MedCalc version 18.2.1 (MedCalc Software, Ostend, Belgium) was used to compare the AUROC among the three prognostic tools. Additional statistical analyses were carried out with IBM SPSS Statistics Version 220.127.116.11 (SPSS Inc., Chicago, IL) and GraphPad Prism Version 8.0.2 (GraphPad Software, San Diego, CA).