Background: A cancer diagnosis has been associated with financial stress, or ‘financial toxicity’. The COmprehensive Score for financial Toxicity (COST) questionnaire is a patient-reported outcome measure from the Functional Assessment of Cancer Therapy (FACT) suite of tools that has been validated in American cancer patients, but not in the Australian setting.
Aim: To demonstrate the validity and reliability of the COST questionnaire in assessing financial toxicity amongst Australian cancer patients.
Methods: A single centre, cross-sectional study design was used to investigate financial toxicity in oncology outpatients. Eligible adults had current malignancy, with or without active anti-cancer treatment. The primary endpoint was the degree of financial toxicity experienced via the COST questionnaire; secondary endpoints include health related quality of life (QOL) (FACT-General), anxiety, and depression (Hospital Anxiety and Depression Scale, HADS). Clinical and demographic data including cancer type, treatment, visit history, age, gender, postcode, income and employment status were recorded. Statistical analysis determined the internal consistency, test-retest reliability and validity of COST, and correlations between COST score and secondary endpoints.
Results: 324 patients were approached, 257 (79%) returning completed questionnaires. 53% of participants were female; median age 63 (range 19-88). COST scores were skewed towards less financial toxicity, median 26 (SD 10.2, range 3- 44), lower scores indicating higher toxicity. High internal consistency (Cronbach’s alpha =0.884) and convergent validity were demonstrated. Financial toxicity was greatest in participants who were younger (≤50), single, non-home owners, unemployed, on short or long-term disability or working part-time; and in the lowest income quintile. Financial toxicity was associated with worse QOL and emotional wellbeing, and with greater depression and anxiety.
Conclusions: The COST measure of financial toxicity demonstrated acceptable validity parameters in an Australian outpatient population. Greater financial toxicity was associated with worse psychological wellbeing and with certain patient demographics. Further multivariate analyses will be presented.