Psychometric properties of the Chinese version of the PROMIS-Cancer-Anxiety item bank assessed using a graded response model

Objective: This study aimed to examine the psychometric properties of the Chinese version of the Patient-Reported Outcome Measurement Information System (PROMIS)-Cancer-Anxiety item bank using a graded response model in a sample of patients with cancer.Methods: A cross-sectional study was conducted and the Chinese version of the PROMIS-Cancer-Anxiety item bank was used to measure anxiety in patients with cancer. The unidimensional structure of the item bank was evaluated using principal component analysis. Residual correlations and the graphs of item mean scores conditional on the rest scores were examined to evaluate the local independence and monotonicity of the items, respectively. Item characteristics were described using item parameter estimates and item information. Operating characteristic curves (OCCs) and test information curve (TIC) were also plotted. Measurement invariance across age, gender, and education level was assessed to identify possible differential item functioning (DIF).Results: A total of 1075 patients with cancer were enrolled. Under the assumptions of unidimensionality, local independence, and monotonicity, the discrimination parameters a ranged from 2.30 to 5.47, and the threshold parameters b ranged from b1 = -2.87 to b4 = 3.21 with proper intervals. Completely overlapped category curves were not observed among the OCCs of any items. Item information and TIC showed that the item bank had a wide measurement range. The DIFs for age, gender, and education level for all items were not remarkable.Conclusions: The results supported using the Chinese version of the PROMIS-Cancer-Anxiety item bank to measure anxiety and develop a computerized adaptive testing (CAT) system for anxiety in patients with cancer.