FIT Instrument Shows Promise for Measuring Patient-Reported Financial Toxicity

An analysis published in Cancer demonstrated that the Financial Index of Toxicity (FIT) instrument is a reliable and accurate tool for measuring patient-reported financial toxicity in patients with head and neck cancer (HNC).

However, the researchers indicated that prospective testing in patients with HNC who were treated at other facilities is necessary to further establish the responsiveness and generalizability of the test.

“The FIT demonstrates content validity with items that cover both subjective and objective measures of toxicity and can be used in conjunction with out-of-pocket cost measurement tools to comprehensively measure financial toxicity,” the authors wrote.

FIT is intended to capture subjective psychological distress associated with finances (financial strain), objective financial burden (financial stress), and lost productivity after cancer treatment. Five instruments were identified that measured at least 1 of these constructs and served as the basis for a preliminary item pool. These included the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire, the Social Difficulties Inventory (SDI), the Personal Finance Wellness Scale, the Social Wellbeing Scale, and the Breast Cancer Finances Survey (BCFS).

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. Ultimately, researchers generated a total of 14 items for FIT, which were subsequently reduced to 9 items.

Overall, the FIT was administered to 430 patients with HNC from a single institution in a publicly funded, single-payer health care system at 12 to 24 months after treatment. Internal consistency of the test was found to be good (α = .77) and test-retest reliability was deemed satisfactory (intraclass correlation, 0.70). Notably, concurrent validation demonstrated mild to strong correlations between the FIT and Social Difficulties Inventory Money Matters subscale (Spearman rho, 0.26-0.61; P < 0.05).

FIT scores were found to be inversely correlated with baseline household income (Spearman rho, -0.34; P < 0.001) and positively correlated with lost income (Spearman rho, 0.24; P < 0.001). Even further, change in income was negatively correlated with change in FIT over time (Spearman rho, -0.25; P = 0.04).

“The FIT demonstrated good internal consistency, satisfactory test-retest reliability, and good construct and concurrent validity,” the authors wrote. “The FIT’s final length of 9 items may make this instrument conducive to patient compliance and easy administration in routine clinical practice, although more research is needed with patient feedback to validate its use in clinical settings.”

Importantly, the investigators highlighted the need for further testing of FIT. Specifically, further analysis was recommended in patients with more advanced cancer, those undergoing palliative treatment, and/or patients with non-HNC primary cancer sites to improve generalizability. In addition, researchers indicated that prospective research is needed to establish responsiveness to changing treatment costs over time and future multicenter studies would ensure generalizability in different health care systems and different socioeconomic climates.

“The FIT accurately identifies patients experiencing greater financial toxicity; further prospective research would establish the validity of the FIT in other disease sites,” the authors concluded. “The FIT is a valuable tool for oncology research and clinical care that can provide guidance for health care decision making.”

Reference:

Hueniken K, Douglas CM, Jethwa AR, et al. Measuring Financial Toxicity Incurred After Treatment of Head and Neck Cancer: Development and Validation of the Financial Index of Toxicity Questionnaire. Cancer. doi:10.1002/cncr.33032.