Validity and reliability of the English and translated Chinese versions of the Integrated Palliative care Outcome Scale (IPOS) in Singapore

Research output: Contribution to journalArticlepeer-review

Authors

  • Victoria Jane En Long
  • Yin Bun Cheung
  • Debra Qu
  • Katherine Lim
  • Guozhang Lee
  • Alethea CP Yee
  • Richard Harding
  • Grace Meijuan Yang

Colleges, School and Institutes

External organisations

  • Duke-NUS Medical School, Singapore
  • National Cancer Centre, Singapore
  • Dover Park Hospice
  • Singapore General Hospital, Singapore
  • King's College London

Abstract

Context: Measurement of patient-centred outcomes enables clinicians to focus on patient and family priorities and enables quality of palliative care to be assessed. Objectives: This study aimed to evaluate the validity and reliability of the English and translated Chinese IPOS among advanced cancer patients in Singapore. Methods: IPOS was forward and backward translated from English into Chinese. Structural validity was assessed by confirmatory factor analysis; known-group validity by comparing inpatients and community patients; construct validity by correlating IPOS with Edmonton Symptom Assessment System-revised (ESAS-r) and Functional Assessment of Cancer Therapy–General (FACT-G); internal consistency by Cronbach’s alpha; inter-rater reliability between patient and staff responses; test-retest reliability of patient responses between two timepoints. Results: 111 English-responding and 109 Chinese-responding patients participated. The three-factor structure (Physical Symptoms, Emotional Symptoms and Communication and Practical Issues) was confirmed with Comparative Fit Index and Tucker-Lewis-Index >0.9 and Root Mean Square Error of Approximation <0.08. Inpatients scored higher than outpatients as hypothesised. Construct validity (Pearson’s correlation coefficient, r≥|0.608|) was shown between the related subscales of IPOS and FACT-G and ESAS-r. Internal consistency was confirmed for total and subscale scores (Cronbach's alpha≥0.84), except for the Communication and Practical Issues subscale (Cronbach’s alpha=0.29-0.65). Inter-rater reliability (Intra-class correlation coefficient [ICC]≤0.43) between patient and staff responses was insufficient. Test-retest reliability was confirmed with Intra-class correlation coefficient ICC=0.80 (English) and 0.88 (Chinese) for IPOS Total. Conclusion: IPOS in English and Chinese showed good validity, good internal consistency, and good test-retest reliability, except for the Communication and Practical Issues subscale. There was poor inter-rater reliability between patients and staff.

Details

Original languageEnglish
Article number40
JournalBMC Palliative Care
Volume20
Publication statusPublished - 9 Mar 2021