Development of the Short Form of the Specific Module of QLICD-BPH (V2.0) for Assessing Quality of Life with Benign Prostatic Hyperplasia by Classical Test Theory, Item Response Theory, and Generalizability Theory

Background Brief measuring instruments for benign prostatic hyperplasia (BPH) that can be implemented in clinical practice are scarce in China, highlighting the need for shorter and more precise instruments. The Quality of Life Instrument for Chronic Diseases–Benign Prostatic Hyperplasia version 2.0 (QLICD-BPH V2.0) has previously demonstrated good validity for reporting BPH. Objective This paper aimed to establish and validate a short form of the BPH-specific module (SPD-16) domain in the QLICD-BPH V2.0 using classical test theory (CTT), generalization theory (GT), item response theory (IRT), and core panel discussion. Design, setting, and participants A total of 141 patients with BPH were recruited to complete the cross-sectional survey at the hospital. Outcome measurements and statistical analysis The QLICD-BPH V2.0 was used, and an ideal structural model for the short form was initially identified through the core panel. The optimal length was then determined as the minimal one that accepted the reliability through the GT analysis of the scale. CTT, IRT, and core panel were used to select a subset of items for the short form. A short form was determined based on qualitative and quantitative analyses, and the internal evaluation was conducted simultaneously. Results The seven-item (SPD-7), which was able to distinguish individuals with BPH traits, was deemed sufficient for use in the short form. Cronbach a for the SPD-7 was 0.854. The SPD-7 had good item-total ( r = 0.600–0.802) and item-item correlation (mean r = 0.445). The coefficient of correlation between the facet scores of the SPD-7 and the SPD-16 ranged from 0.783 to 0.979 ( p < 0.01), indicating good convergent validity. Significant correlations between the SPD-7 and the SPD-16 ( r = 0.910, p < 0.01) supported convergent validity. Conclusions The SPD-7 showed good reliability and validity and can be used as an effective tool to evaluate the quality of life of patients with BPH.