Development and Validation of Subjective Financial Distress Questionnaire (SFDQ): A Patient Reported Outcome Measure for Assessment of Financial Toxicity Among Radiation Oncology Patients

Abstract

BackgroundFinancial toxicity is a consequence of subjective financial distress experienced by cancer patients as a result of treatment expenditures. Financial toxicity has been associated with poor quality of life, early mortality, and non-adherence. It is evident from the literature that the currently available instruments for the assessment of financial toxicity do not measure coping and support seeking domains. The aim of this study was to develop an instrument for the assessment of financial toxicity among radiation oncology patients that captures and integrates all the relevant domains of subjective financial distress.Materials and MethodsThe study was conducted among Head & Neck cancer (HNC) patients (age ≥18 years) who have completed the radiotherapy either as stand-alone or part of a multimodal treatment. Literature review, expert opinion, and patient interviews were used for scale item generation. The validity and underlying factor structure were evaluated by Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA). The reliability and internal consistency of the final scale was assessed using Cronbach’s alpha coefficient.ResultsA total of 17 items were identified for scale development. The preliminary 17-item instrument was administered to 142 HNC patients. Among 142 participants, 85.9% were male and 98.6% were from rural areas. EFA was performed on 17 items and three items were removed (factor loadings <0.5). The remaining 14 items loaded onto three factors (eigenvalue >1) explaining 62.0% of the total variance. The Chi-square goodness of fit test in CFA and the values of other model fit indices, namely, RMSEA = 0.045, SRMR = 0.014, GFI = 0.92, CFI = 0.98, and TLI=0.97 indicate a good model fit suggesting the three-factor model adequately fits the data. The Cronbach’s α for the final 14-item scale was 0.87 indicating excellent reliability and the Cronbach’s α coefficient of all the individual 14 items was ≥0.85 (range 0.85–0.88).ConclusionThe SFDQ showed excellent validity and reliability. SFDQ captures and integrates all the relevant domains of financial toxicity. However, the provisional SFDQ instrument warrants further larger sample studies for validation and psychometric evaluation in different primary cancer subsites and treatment modalities from multiple cancer centers to improve the generalizability of this instrument.

Psychometric properties of self-reported financial toxicity measures in cancer survivors: a systematic review

“…After duplications were removed, a total of 11 731 articles were retained, 11 669 articles were deleted after reading the title and abstract, and 39 were deleted after full-text reading. Finally, a total of 23 articles (21 PROMs) were eligible for inclusion in this study 12 14 16 23–42…”

“…All included studies were published from 2005 to 2022. Eight studies were conducted in the USA,12 14 23 27 30 37 39 41 four in the UK,16 29 35 38 two in Canada31 36 and two in China (mainland and Hong Kong),25 39 India26 34 and Italy 33 42. One study was conducted in 12 countries in Europe and North America 22 23.…”

“…Among the 21 PROMs, 7 were FT-related domains of quality of life PROMs and 14 were independent PROMs focusing on FT. All PROMs were validated in cancer survivors. Fifteen PROMs were in English,12 14 16 23 25–31 35 37 38 40–42 and two were in Chinese 24 39. Other languages included French,36 Portuguese,32 Italian,33 42 Hindi25 26 and Persian 34.…”

“…Fifteen PROMs were in English,12 14 16 23 25–31 35 37 38 40–42 and two were in Chinese 24 39. Other languages included French,36 Portuguese,32 Italian,33 42 Hindi25 26 and Persian 34. The number of items evaluating FT ranged from 340 to 23 36.…”

“…Table 3 shows the quality of the psychometric properties retrieved from 21 PROMs. Only the Persian version of the COST-v2 and Subjective Financial Distress Questionnaire (SFDQ) were rated as ‘+’ in structural validity 26 34. There were 17 PROMs rated as ‘+’ in internal consistency 12 14 16 23 24 26–29 31 32 34 35 37–39 41 42.…”