Reliability and validity of the Arabic translation of the palliative performance scale

Objective The aim of this study was to translate the Palliative Performance Scale (PPSv2) into Arabic and to test the reliability and validity of the PPS Arabic translation (PPS-Arabic). Method The PPSv2 was translated into Modern Standard Arabic using a forward-backward method. Inter-rater and intra-rater reliabilities were tested in a pilot study that included 20 patients. The validation study included 150 cancer patients. Patients were divided according to their treatment plan into three groups (in-remission, palliative chemotherapy, and best supportive care) to perform hypothesis-testing construct validity. Validity was further evaluated by correlating PPS-Arabic with the Karnofsky Performance Scale (KPS), the Eastern Cooperative Oncology Group (ECOG) scale, and Physical Functioning (PF2) and Role Functioning (RF2) scales of the European Organization for Research and Treatment of Cancer quality of life questionnaire (EORTC QLQ-C30). Results The intraclass correlation coefficients for the intra-rater and inter-rater reliability were 0.935 (95% CI: 0.88-0.965; p < 0.001) and 0.965 (95% CI: 0.934-0.981; p < 0.001), respectively. The PPS-Arabic internal consistency Cronbach's alpha was 0.986. The average PPS-Arabic score differed significantly (p < 0.001) between the three groups of patients being 89 for in-remission, 58 for palliative chemotherapy, and 38 for best supportive care. The PPS-Arabic score correlated significantly (p < 0.001) with the KPS, ECOG performance scale, and the EORTC QLQ-C30 PF2 and RF2 scales. Conclusion The PPS-Arabic is a reliable and valid tool for the assessment of performance status of cancer patients.