Who determines nasopharyngeal carcinoma inpatients' medical expenditure? Importance factor ranking using the random forest model.

Background: Nasopharyngeal carcinoma (NPC) is a malignant epithelial tumor most commonly in China. In 2013, NPC incidence and mortality in China were also at high levels worldwide, which poses a great health burden in China. This study analyzes the medical expenditure and influencing factors of inpatients with NPC and aims to provide reference suggestions for reducing medical expenditure for NPC. Methods: Based on the data from one of the western China hospitals, we use the random forest model to identify the important factors in total medical expenditure, out-of-pocket costs, and the rates of out-of-pocket costs. Results: Total medical expenditure, out-of-pocket costs, and the rates of out-of-pocket costs were decreased. According to the indicators of InNodePurti and %IncMSE, the top three influencing factors of total medical expenditure and out-of-pocket costs are Length of stay, Medical payment method, and Readmission status; the top three influencing factors of the rates of out-of-pocket costs are Medical payment method, Occupation, and Age. Conclusion: Length of stay was an important factor in total medical expenditure and out-of-pocket costs, and the medical payment method was an important factor in the rates of out-of-pocket costs. To reduce the burden of NPC patients' medical expenditure, (1) we can reduce the length of stay by improving the level of medical technology; (2) increasing government medical expenditures and improving the level of medical security; (3)promoting smoking bans, and strengthening screening in high-risk areas.