Short-form adaptive measure of financial toxicity from the Economic Strain and Resilience in Cancer (ENRICh) study: Derivation using modern psychometric techniques

Objectives This study sought to evaluate advanced psychometric properties of the 15-item Economic Strain and Resilience in Cancer (ENRICh) measure of financial toxicity for cancer patients. Methods We surveyed 515 cancer patients in the greater Houston metropolitan area using ENRICh from March 2019 to March 2020. We conducted a series of factor analyses alongside parametric and non-parametric item response theory (IRT) assessments using Mokken analysis and the graded response model (GRM). We utilized parameters derived from the GRM to run a simulated computerized adaptive test (CAT) assessment. Results Among participants, mean age was 58.49 years and 278 (54%) were female. The initial round factor analysis results suggested a one-factor scale structure. Negligible levels of differential item functioning (DIF) were evident between eight items. Three items were removed due to local interdependence (Q3>+0.4). The original 11-point numerical rating scale did not function well, and a new 3-point scoring system was implemented. The final 12-item ENRICh had acceptable fit to the GRM (p<0.001; TLI = 0.94; CFI = 0.95; RMSEA = 0.09; RMSR = 0.06) as well as good scalability and dimensionality. We observed high correlation between CAT version scores and the 12-item measure (r = 0.98). During CAT, items 2 (money you owe) and 4 (stress level about finances) were most frequently administered, followed by items 1 (money in savings) and 5 (ability to pay bills). Scores from these four items alone were strongly correlated with that of the 12-item ENRICh (r = 0.96). Conclusion These CAT and 4-item versions provide options for quick screening in clinical practice and low-burden assessment in research.