Abstract: Objective: To analyze the decision-making process of health behaviors in patients with type 2 diabetes mellitus using bounded rationality decision theory, and to provide a reference for improving health behaviors in patients with type 2 diabetes mellitus. Methods: A purposive sampling method was used to conduct semi-structured interviews with 17 patients with type 2 diabetes mellitus in a tertiary grade A hospital and community medical center in Lanzhou from May to October 2023. The themes were summarized and distilled by deductive content analysis. Results: A model of decision-making bias in health behavior of type 2 diabetes mellitus patients was developed, which included 4 periods of information reception, option analysis, option selection and outcome evaluation, 9 types of decision-making bias in health behavior, and 14 types of manifestations of decision-making bias affecting health behavior. Conclusion: Decision-making of health behaviors in type 2 diabetes mellitus patients is a multifactorial process. It is recommended that healthcare professionals reconstruct correct health information during the information reception period, overcome misinformation interference during the option analysis period, facilitate health option selection during the option selection period, and quantify decision evaluation criteria during the outcome evaluation period.

Key words: type 2 diabetes mellitus; bounded rationality; health behavior; decision-making bias; qualitative research