To analyze the differences in inpatient cost structure and variation between patients discharged against medical advice (DAMA) and those discharged per medical advice (DC) under the DRG payment model, aiming to support resource optimization and risk communication strategies.

Front-page medical records of all DAMA and DC inpatients from a tertiary general hospital between 2020 and 2024 were collected. Descriptive statistics and univariate analysis were used to compare cost differences. Cluster analysis and structural variation degree analysis were conducted to examine cost composition and annual variation trends.

Significant differences were found between the two groups in total and itemized inpatient costs. DAMA patients exhibited a “majority low-cost, minority high-expenditure” pattern, dominated by drug expenses and relatively low treatment costs. In contrast, DC patients showed more balanced cost distribution with stable proportions of diagnostic, treatment, and drug costs. Structural variation analysis indicated greater variation among DC patients, driven by changes in treatment and general medical service fees, while DAMA patients were mainly affected by diagnostic cost fluctuations.

Medical institutions should prioritize optimizing the cost structure of DAMA patients to enhance resource allocation and cost control, promoting standardized clinical practice and effective use of medical insurance funds under DRG reform.