ZHANG Jiawei, WANG Jianqiang, WANG Xiaokang, CHEN Haoze, HOU Wenhui, LIU Ye
Accepted: 2026-08-13
With the deepening of medical insurance payment system reforms, some medical institutions engage in fraudulent practices by upcoding disease diagnosis codes to illicitly obtain medical insurance funds, seriously undermining the equity and sustainability of the fund. Existing methods suffer from insufficient utilization of heterogeneous textual data and limited model interpretability. To address these challenges, this study proposes an intelligent identification framework integrating three-way decision theory and hybrid supervised machine learning. For heterogeneous insurance data comprising numerical, textual, and temporal types, a multi-type feature construction strategy is developed: statistical aggregation captures cost distribution characteristics, Skip-gram and BioBERT models transform diagnosis codes and clinical texts into semantic vector representations, and sliding-window statistics encode temporal dynamics. Guided by the three-way decision framework, features are partitioned into acceptance, rejection, and boundary domains; granular-ball attribute reduction is subsequently applied to the boundary domain for refined feature selection. An improved osprey optimization algorithm (IOOA) incorporating chaotic mapping, elite opposition-based learning, Gaussian mutation, and adaptive nonlinear convergence factors is proposed to jointly optimize the Bayesian network (BN) structure and the regularization and kernel-width parameters of the least squares support vector machine (LSSVM). Prior and posterior probabilities derived from the BN are incorporated as augmented inputs to the LSSVM, simultaneously enhancing interpretability and classification performance. Experiments on a real desensitized medical insurance dataset comprising 28,231 records from 5,000 patients show that the proposed IOOA-BN-LSSVM model achieves an accuracy of 0.9565, recall of 0.9440, precision of 0.9557, and F1-score of 0.9498, outperforming six benchmark methods including logistic regression, random forest, and LightGBM. The proposed method offers medical insurance regulatory authorities an efficient, accurate, and interpretable intelligent audit tool with strong practical application value.