Quality of Care for Patients With Advanced Illness Scale: Development, Preference Elicitation, and Evaluation of Measurement Properties

Abstract

Objectives: To develop the Quality of Care for Patients with Advanced Illness (QCPAI) scale, derive preference-weighted scoring, and evaluate measurement properties for comprehensively assessing advanced care quality from the patient's perspective. Methods: A 15-item QCPAI scale, including self-administered and caregiver proxy versions, was developed through a 5-step process (scoping review, item development, translation, cognitive debriefing, and reconciliation) in English and Chinese. A study was conducted among 200 advanced cancer patients and their caregivers, with baseline and 1-week follow-up surveys. A preference-weighted scoring system was derived using best-worst scaling among patients. Measurement properties evaluated included criterion validity, known-group validity, test-retest reliability, equivalence of self-administered and proxy responses, and equivalence between language versions. Results: Respondents ranked medical treatment, symptom control, and cost as the most important aspects of care. Criterion validity was supported by a strong correlation (ρ > 0.5) between the QCPAI score and satisfaction with overall care. Known-group validity based on patients with varying levels of quality of life demonstrated significantly different mean QCPAI scores. Test-retest reliability was confirmed with an intraclass correlation coefficient exceeding 0.75. Equivalence was demonstrated between English and Chinese versions and between patient self-reports and caregiver proxy responses (standardized effect size ≤ 0.2). Conclusions: The QCPAI scale exhibits robust validity and reliability in measuring the quality of advanced illness care. Healthcare organizations and policy makers are encouraged to adopt the QCPAI scale as a standard tool for systematically evaluating and enhancing care quality.