Identifying a cut-off score for the COST measure to indicate high financial toxicity and low quality of life among cancer patients

Purpose To identify a cut-off score for the COmprehensive Score for financial Toxicity (COST) to predict a clinical implication of a high level of financial toxicity (FT). Methods A total of 640 cancer patients were recruited from three regional hospitals in Hong Kong. They completed a questionnaire comprising the COST measure and the Functional Assessment of Cancer Therapy - General (FACT-G) instrument. The cut-off score for the COST that predicts the lowest quartile of the FACT-G total score was identified by receiver operating characteristic (ROC) analysis. The sample was then stratified by this cut-off score, and characteristics were compared using Fisher’s exact, chi-squared or independent sample t-test. Results The mean scores were 20.1 ± 8.8 for the COST and 71.6 ± 15.5 for the FACT-G. The ROC analysis suggested that the cut-off of 17.5 yielded an acceptable sensitivity and specificity. Characteristics of patients with a higher level of FT included being younger, having a monthly household income of