Palliative Performance Scale: Cross cultural adaptation and psychometric validation for Polish hospice setting

Abstract Background: Measuring functional status in palliative care may help clinicians to assess a patient’s prognosis, recommend adequate therapy, avoid futile or aggressive medical care, consider hospice referral, and evaluate provided rehabilitation outcomes. An optimized, widely used, and validated tool is preferable. The Palliative Performance Scale Version 2 (PPSv2) is currently one of the most commonly used performance scales in palliative settings. The aim of this study is the psychometric validation process of a Polish translation of this tool (PPSv2-Polish). Methods: Two hundred patients admitted to a free-standing hospice were evaluated twice, on the first and third day, for test-retest reliability. In the first evaluation, two different care providers independently evaluated the same patient to establish inter-rater reliability values. PPSv2-Polish was evaluated simultaneously with the Karnofsky Performance Score (KPS), Eastern Cooperative Oncology Group (ECOG) Performance Status (ECOG PS), and Barthel Activities of Daily Living (ADL) Index, to determine its construct validity. Results: A high level of full agreement between test and retest was seen (63%), and a good intra-class correlation coefficient of 0.85 (P<0.0001) was achieved. Excellent agreement between raters was observed when using PPSv2-Polish (Cohen’s kappa 0.91; P<0.0001). Satisfactory correlations with the KPS and good correlations with ECOG PS and Barthel ADL were noticed. Persons who had shorter prognoses and were predominantly bedridden also had lower scores measured by the PPSv2-Polish, KPS and Barthel ADL. A strong correlation of 0.77 between PPSv2-Polish scores and survival time was noted (P<0.0001). Moderate survival correlations were seen between KPS, ECOG PS, and Barthel ADL of 0.41; -0.62; and 0.58, respectively (P<0.0001). Conclusion: PPSv2-Polish is a valid and reliable tool measuring performance status in a hospice population and can be used in daily clinical practice in palliative care and research.