Validity and Reliability of the Integrated Palliative Care Outcome Scale in Asian Heart Failure Patients

BACKGROUND: The Integrated Palliative Care Outcome Scale (IPOS) was developed in the United Kingdom for health assessment in advanced illness. OBJECTIVES: To evaluate the validity and reliability of a culturally adapted IPOS (both patient and staff versions) for heart failure (HF). DESIGN/SETTING: We recruited HF patients and staff from a tertiary hospital in Singapore. We collected patient IPOS, New York Heart Association (NYHA) status, Edmonton Symptom Assessment System (ESAS) and Minnesota Living with Heart Failure (MLHF) scores at baseline, and patient IPOS at follow-up. Each baseline patient IPOS was matched with a staff IPOS. MEASUREMENTS: Pearson correlation coefficient (r) between ESAS, MLHF, and patient IPOS was calculated to assess construct validity. The two-sample T-test assessed difference in patient and staff IPOS scores across NYHA status and care settings for known-group validity. Internal consistency of patient and staff IPOS was assessed using Cronbach's alpha (α). Intraclass correlation coefficient (ICC) was used to assess test-retest reliability of patient IPOS and inter-rater reliability between patient and staff IPOS. RESULTS: Ninety-one patients and 12 staff participated. There was strong convergent validity of total patient IPOS with MLHF (r = 0.78) and ESAS (r = 0.81). There were statistically significant differences in total IPOS across care settings (patient-IPOS: 8.05, staff-IPOS 13.61) and NYHA (patient-IPOS: 7.52, staff-IPOS 12.71). There was high internal consistency of total patient (α = 0.83) and staff IPOS (α = 0.88) and high test-retest reliability of patient IPOS (ICC 0.81). Inter-rater reliability (ICC) ranged between 0.82 and 0.91. CONCLUSION: The IPOS was valid and reliable for HF patients in Singapore.