Korean version of the Caregiver Quality of Life Index Cancer (CQOLC-K)

Objective: The aim of this study was to develop and evaluate the internal consistency and construct validity of a Korean version of the Caregiver Quality of Life Index - Cancer (CQOLC-K). Methods: The CQOLC-K was administered to 270 caregivers, along with the Medical Outcomes Study Short Form-36 (SF-36) and the Beck Depression Inventory (BDI). Results: Internal consistency of the CQOLC-K (0.90) and all inter-scale correlations were significant in the expected direction (p < 0.001). Convergent validity was supported with moderate to strong correlations between the CQOLC-K and the mental component scores of the SF-36 (r = 0.39-0.58), and between the CQOLC-K and the two BDI scores (r = 0.50 and 0.60). Divergent validity was supported by weaker or negligible correlations between the CQOLC-K and the physical component scores of the SF-36 (r = 0.16-0.30). Contrasting groups validity showed that the CQOLC-K was able to distinguish clearly between patients differing in treatment history (p < 0.005), performance status (p < 0.005), care area (p < 0.005), and length of time after diagnosis (p < 0.005). Conclusion: These findings support the internal consistency reliability and construct validity of the Korean version of the CQOLC-K. The instrument can be used to measure quality of life in caregivers of cancer patients in clinical and epidemiological research.