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Measuring financial toxicity incurred after treatment of head and neck cancer: Development and validation of the Financial Index of Toxicity questionnaire
Author(s) -
Hueniken Katrina,
Douglas Catriona M.,
Jethwa Ashok R.,
Mirshams Maryam,
Eng Lawson,
Hope Andrew,
Chepeha Douglas B.,
Goldstein David P.,
Ringash Jolie,
Hansen Aaron,
Martino Rosemary,
Li Madeline,
Liu Geoffrey,
Xu Wei,
Almeida John R.
Publication year - 2020
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.33032
Subject(s) - intraclass correlation , exploratory factor analysis , medicine , cronbach's alpha , test (biology) , psychology , psychometrics , clinical psychology , paleontology , biology
Background The treatment of head and neck cancer (HNC) may cause significant financial toxicity to patients. Herein, the authors have presented the development and validation of the Financial Index of Toxicity (FIT) instrument. Methods Items were generated using literature review and were based on expert opinion. In item reduction, items with factor loadings of a magnitude <0.3 in exploratory factor analysis and inverse correlations (r < 0) in test‐retest analysis were eliminated. Retained items constituted the FIT. Reliability tests included internal consistency (Cronbach α) and test‐retest reliability (intraclass correlation). Validity was tested using the Spearman rho by comparing FIT scores with baseline income, posttreatment lost income, and the Financial Concerns subscale of the Social Difficulties Inventory. Responsiveness analysis compared change in income and change in FIT between 12 and 24 months. Results A total of 14 items were generated and subsequently reduced to 9 items comprising 3 domains identified on exploratory factor analysis: financial stress, financial strain, and lost productivity. The FIT was administered to 430 patients with HNC at 12 to 24 months after treatment. Internal consistency was good (α = .77). Test‐retest reliability was satisfactory (intraclass correlation, 0.70). Concurrent validation demonstrated mild to strong correlations between the FIT and Social Difficulties Inventory Money Matters subscale (Spearman rho, 0.26‐0.61; P < .05). FIT scores were found to be inversely correlated with baseline household income (Spearman rho, −0.34; P < .001) and positively correlated with lost income (Spearman rho, 0.24; P < .001). Change in income was negatively correlated with change in FIT over time (Spearman rho, −0.25; P = .04). Conclusions The 9‐item FIT demonstrated internal and test‐retest reliability as well as concurrent and construct validity. Prospective testing in patients with HNC who were treated at other facilities is needed to further establish its responsiveness and generalizability.