Validation of the COmprehensive Score for Financial Toxicity (COST) in Vietnamese patients with cancer

• Published in: PloS one 2024-06, Vol.19 (6), p.e0306339
• Main Authors: Tran, Binh Thang, Le, Dinh Duong, Nguyen, Thanh Gia, Nguyen, Minh Tu, Nguyen, Minh Hanh, Dang, Cao Khoa, Tran, Dinh Trung
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; Analysis; Breast cancer; Cancer; Cancer patients; Chi-square test; Colorectal cancer; Confidence intervals; Cost of Illness; Cross-Sectional Studies; Economic aspects; Education; Factor analysis; Female; Gastric cancer; Health insurance; Hospital patients; Humans; Liver cancer; Local culture; Male; Medical care, Cost of; Medical colleges; Medical research; Medicine, Experimental; Middle Aged; Neoplasms - economics; Patients; Public health; Quality of life; Regression analysis; Reliability; Reproducibility of Results; Southeast Asian People; Statistical analysis; Statistical tests; Surveys and Questionnaires; Toxicity; Validation studies; Validity; Variables; Vietnam
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0306339

The COmprehensive Score for Financial Toxicity (COST) has proven to be a reliable tool for quantifying the impact of financial toxicity (FT) in patients with cancer in clinical and public health settings. However, the COST has not yet been validated in Vietnam. Therefore, we aimed to evaluate its reliability and validity among Vietnamese patients with cancer. A cross-sectional study was conducted in a sample of 300 patients with cancer aged 27-95 years (mean: 58.5±11.2) in a tertiary hospital. The COST was translated into Vietnamese and English and adjusted to suit the local culture. Reliability was evaluated using Cronbach's alpha and McDonald's omega coefficients. The construct and convergent validities were also assessed. The COST demonstrated good internal consistency and reliability (Cronbach's alpha = 0.913; McDonald's omega = 0.915). The exploratory factor analysis revealed two factors that explained 64.9% of the variance. The adjusted fit indices indicated a good fit of the model (χ2 (39) = 67.78, p = 0.003; standardized root mean squared residual = 0.042; Tucker-Lewis index = 0.971; comparative fit index = 0.979; root mean square error of approximation = 0.061, 90% confidence interval = 0.035-0084). Higher COST scores were significantly correlated with higher health-related quality of life (EQ-5D-5L utility score: r = 0.21, p = 0.002; EQ VAS: r = 0.28, p < 0.001). Multivariate quantile regression analysis revealed that female sex, rural residence, and unstable job/unemployment were associated with lower COST scores. There was no statistically significant difference in other factors, including clinical factors (types of cancer, staging, and treatment modalities). The COST is reliable and valid, making it suitable for assessing FT severity in Vietnamese patients with cancer.