Measuring financial toxicity in Australian cancer patients – Validation of the COmprehensive Score for financial Toxicity (FACT COST) measuring financial toxicity in Australian cancer patients

Aim/Background: The FACT COST is a patient-rated measure of financial toxicity, developed and validated in a North American population. We aimed to confirm the validity and reliability of the FACT COST in Australian cancer patients, because the Australian healthcare funding structure is different to that in North America. Methods: A single center, cross-sectional study design investigated financial toxicity in oncology outpatients. Eligible adults had current malignancy, with or without active cancer treatment. The primary endpoint was the degree of financial toxicity experienced via the COST questionnaire; secondary endpoints included health-related quality of life (Functional Assessment of Cancer Therapy-General), anxiety, and depression (Hospital Anxiety and Depression Scale). Clinical and demographic data were recorded. Statistical analysis determined the internal consistency, test-retest reliability and validity of COST, and correlations between COST score and secondary endpoints. Results: A total of 257 patients participated (79% response rate). Fifty-three percent were female; median age 63 years (range 19-88). COST scores were skewed toward less financial toxicity, median 26 (SD 10.3, range 1-43), lower scores indicating higher toxicity. High internal consistency (Cronbach's α = 0.884), test-retest reliability (ICC = 0.801), and convergent validity were demonstrated. Financial toxicity was greatest in younger participants, those with more inpatient admissions, those with a change in employment status following diagnosis, and those in the lowest income quintile. Financial toxicity was associated with worse health-related quality of life, and greater depression and anxiety. Conclusion: The COST measure of financial toxicity demonstrated acceptable validity parameters in an Australian outpatient population. Greater financial toxicity was associated with worse psychological well-being and with certain patient demographics.