A multicenter longitudinal study on development and validation of the quality of life scale QLICD-DM (V2.0) for diabetes mellitus based on classical test theory and generalizability theory.

Quality of life (QOL) research in diabetes has long been a concern with many specific instruments being developed, but no scale for diabetes has been developed based on the modular approach. This study aimed to develop and validate the Diabetes Mellitus Scale of the System of Quality of Life Instruments for Chronic Diseases QLICD-DM (V2.0) by a modular approach and mixed methods.