Abstract

Objectives

This study explored health-related quality of life (HRQoL) among Malaysians with heart failure (HF) and compared self-reported and proxy-reported HRQoL to assess the presence, direction, and magnitude of proxy response bias.

Methods

HF outpatients across Malaysia completed the Assessment of Quality of Life (AQoL-6D) questionnaire, either personally or via a caretaker-proxy, adopting a proxy-proxy perspective. Sociodemographic and clinical data were collected. Propensity score matching was used to ensure comparability between self- and proxy-reported HRQoL. Sensitivity analyses were conducted to examine results across various matching algorithms.

Results

Among 419 HF outpatients (mean age: 57 years, New York Heart Association class II-IV 48%) who provided AQoL-6D data, 28% were proxy-reported. The mean overall AQoL-6D score was 74.7, with the Relationships and Coping dimensions scoring lowest. Proxy-reported HRQoL was consistently worse than self-reports, with small-to-moderate differences observed across most dimensions (standardized mean difference: 0.41-1.03) and items (relative risk of reported problems in proxy-reports compared with self-reports: 1.25-3.46). These discrepancies persisted in propensity-score-matched pairs (n = 97), indicating proxy response bias, although the differences were reduced in magnitude (standardized mean difference: 0.33-0.76; relative risk: 1.22-3.00). Differences were most pronounced in items related to physical and functional limitations.

Conclusion

This study provides insights into HRQoL and the high prevalence of proxy responses among Malaysians with HF. Although proxy reporting can be informative, clinicians should interpret proxy-reported HRQoL cautiously, particularly in physical and functional domains, because of small-to-moderate deviations from self-reports.