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

Victoria Jane En Long,Grace Meijuan Yang,Ping Guo,Debra Qu,Katherine Lim,Guozhang Lee,Yin Bun Cheung,Richard Harding,Alethea C P Yee

doi:10.1186/s12904-021-00737-y

Abstract

ContextMeasurement of patient-centred outcomes enables clinicians to focus on patient and family priorities and enables quality of palliative care to be assessed.ObjectivesThis study aimed to evaluate the validity and reliability of the English and translated Chinese versions of the Integrated Palliative care Outcome Scale (IPOS) among advanced cancer patients in Singapore.MethodsIPOS 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.ResultsOne hundred eleven 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.ConclusionIPOS 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.

Highlights

Patient reported outcome measures (PROMs) are patient-centred questionnaires that measure perceived functional status and wellbeing [1]
Key message This article demonstrates that the Integrated Palliative care Outcome Scale (IPOS) and its translated Chinese version is a valid tool to measure palliative care outcomes in advanced cancer patients in Singapore
86 and 79 participants who answered the English and Chinese questionnaires respectively had a staff member in their healthcare team respond at baseline; 70 English questionnaire responders and 62 Chinese questionnaire responders had a staff IPOS response at follow-up (Table 1)

Summary

Introduction

Patient reported outcome measures (PROMs) are patient-centred questionnaires that measure perceived functional status and wellbeing [1]. PROMs facilitate clinical practice by promoting patient-centred communication, screening for unmet needs and monitoring the severity of problems related to disease or treatment toxicity [3]. Such patient-centred data is useful in palliative care, improving awareness of unmet need, enabling professionals to act to address patients’ needs, and benefitting patients’ emotional and psychological quality of life [4]. Palliative care involves comprehensive assessment and management of problems in multiple domains. A brief measure is needed for the context of palliative care

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