Development of the quality of life of family caregivers of advanced cancer patients scale in Japan: Psychometric properties

Objective: We aimed to develop a new scale for use in Japan, called the "Quality of Life of Family Caregivers of Advanced Cancer Patients Scale (QFCS)" and to examine its psychometric properties.

Methods: A draft scale was extracted based on qualitative inductive and deductive analyses, and its content validity and surface validity were investigated. Its psychometric properties were examined.

Results: The QFCS consists of 30 items comprising four factors. Cronbach's α was 0.92 and the intraclass correlation coefficient was 0.90. Correlation coefficients between the total QFCS score and eight subscale scores of the revised Medical Outcomes Study 12-Item Short Form Survey Instrument were rs ​= ​0.22-0.65 (P ​< ​0.01-0.05). The Physical Component Summary was r ​= ​0.29 (P ​< ​0.01), and the Mental Component Summary was r ​= ​0.67 (P ​< ​0.01). Correlation coefficients between the QFCS total score and four subscale scores of the Caregiver Quality of Life Index-Cancer (CQOLC) were r ​= ​0.27-0.59 (P ​<0 ​.01) and the CQOLC total score was r ​= ​0.65 (P ​<0 ​.01).

Conclusions: Our results suggest that the QFCS exhibited acceptable psychometric properties in measuring the quality of life of family caregivers of patients with advanced cancer. Future research is needed to evaluate the effectiveness and quality of family support using the QFCS.