The effects of financial toxicity on health-related quality of life and treatment adherence in cancer patients

The aim of this study is to determine the level of financial toxicity in cancer patients, to identify the risk factors (socio-demographic characteristics of the patient and patient's family, financial condition and employment related characteristics and disease and treatment related characteristics) associated with this level and reveal the effect of it on treatment non-adherence and health-related quality of life by adapting the COST Measure (v2), which was developed to measure the financial toxicity of cancer patients, into Turkish. In this context, data obtained from 316 patients aged 18 and over, who received chemotherapy for at least 3 months and who received inpatient treatment in an oncology hospital in Ankara, were evaluated. The data were collected by the researcher through a face-to-face interview with the patients via a questionnaire. In the questionnaire, besides the COST Measure, the FACT-G Scale (v4) was used to evaluate health-related quality of life, and a questionnaire created by reviewing the literature was used to measure treatment adherence. Factor analysis and Cronbach's alpha coefficient were used in the adaptation of the COST Measure into Turkish, and univariate analysis and multiple logistic regression analysis were also used to determine the risk factors associated with the financial toxicity. Correlation, multiple linear and multiple logistic regression analysis were used to evaluate the impact of financial toxicity on patient outcomes. As a result of the analysis, it was determined that the Turkish version of the COST Measure is valid and reliable, cancer patients experience higher than moderate financial toxicity, and younger age, being married, having a low level of education and low monthly household income, and receiving social/economic support from an institution for treatment were determinants of financial toxicity. It was also found that as the perceived financial toxicity level increased, patients' probability of treatment non-adherence increased and their health-related quality of life decreased.