Validation of the comprehensive score for financial toxicity for Brazilian culture

Abstract

Financial toxicity is a side effect of cancer treatment showing the financial burden experienced by cancer patients for funding their treatment. An instrument for its evaluation can contribute towards the creation of coping strategies. In Brazil, a developing country, cancer patients certainly feel the effects of this serious adverse event, however, the discussion on the theme and research concerning these issues is scarce and an instrument for evaluation can help in the promotion of coping strategies. Thus, the study objective was to: 1) translate and adapt the COmprehensive Score for financial Toxicity (COST) questionnaire to Brazilian culture and 2) evaluate the COST psychometric properties in Brazil. Thus, a methodological study was developed in two stages. In the first stage, the translation and cross-cultural adaptation were performed, and in the second stage, two groups of participants were recruited to evaluate the psychometric properties. In the first stage, 21 individuals participated, including translators and cancer patients, and in the second stage, 126 patients participated who were undergoing cancer treatment. For validation, exploratory factor analysis (EFA), confirmatory factor analysis (CFA) and Cronbach’s alpha coefficient were performed to verify internal consistency. For the first stage’s outcome, the pre-test Cronbach’s alpha was 0.83. The EFA and CFA carried out in the second stage of the study revealed that the COST Brazilian version measures a single construct with a value of—χ2/gl = 179.78, comparative fit index = 0.00, Parsimony goodness of fit index = 0.302, root mean square error of approximation = 1.196 and p-value of close fit = 0.000. When comparing the average of the COST score and the standard deviation of the two samples, the significance value was p = 0.001. Therefore, it is possible to confirm that the COST is a valid and reliable questionnaire to measure the financial toxicity of cancer patients in Brazil.

Assessing the reliability and validity of comprehensive score for financial toxicity (COST) among radiation oncology patients in India: a cross-sectional pilot study

“…The results of our pilot study show that internal consistency of COST measure was excellent with a Cronbach's α of 0.92 and no increase in Cronbach's α values was observed if any individual items were deleted, corroborating with the results of the original COST development study (Cronbach's α = 0.92) [16]. The Cronbach's α coefficient was higher in this study as compared to validation studies in Japanese, Italian and Brazilian studies which reported a Cronbach's α of 0.87, 0.83 and 0.82, respectively [23][24][25].…”

“…Again, these results were comparable with the original COST development study which reported a KMO of 0.9 [ 16 ]. The KMO value observed in this study (0.87) was higher as compared to the KMO values of Italian (0.82), and Brazilian (0.81) validation studies [ 24 , 25 ]. The suitability of data for EFA was also demonstrated using multivariate normality, factorability and multicollinearity analysis.…”

“…COST validation studies conducted in Italy and Brazil reported a two-factor model; however, one factor model best represents the COST measure, and that factor was designated as FT [16,24,25]. The %age variance explained was lower in this study as compared to the parent COST study (89%) and Italian version (63%) but higher than the Brazilian version (51.6%) [16,24,25].…”

“…A total of 70/110 correlation combinations were significant based on p- value indicating 63.6% significant correlation. These results were lower as compared to Brazilian version of COST which showed 78.2% significant correlations on Spearman’s correlation test [ 25 ]. However, this study showed higher number of large effect size correlations combinations (31) in all items as compared to Brazilian version which reported only three stronger correlation combinations in all items.…”

“…The COST measure has already been validated for assessment of FT in different cancer care settings across the USA including advanced solid tumours [ 17 ], radiation oncology [ 18 ], gynaecologic oncology [ 19 ], multiple myeloma [ 20 ], lung cancer [ 21 ] and surgery [ 22 ]. COST measure has also been translated and adapted for use in different healthcare systems by other countries including Japan [ 23 ], Italy [ 24 ] and Brazil [ 25 ].…”