Both excessive utilization and underutilization of medical services affect the fairness in the use of medical services. Therefore, studying the concentration of healthcare expenditures on chronic diseases, and analyzing the characteristics of patients with high and low medical expenditures could assess the fairness of the essential medical insurance system.

To analyze the concentration of healthcare expenditures in type 2 diabetes mellitus (T2DM) patients with essential medical insurance coverage.

Data of patients with a first diagnosis of T2DM and coverage of essential medical insurance were collected from the information system of a municipal medical insurance center in Jiangsu Province in July 2019, involving 24 107 cases with urban resident basic medical insurance (URBMI) and 109 265 cases with urban employee basic medical insurance (UEBMI) . Patients in each group were subgroup by the level of personal healthcare expenditure from high to low (percentile subgroups 1-5: top 1%, top 1%-5%, top 5%-10%, top 10%-50% and the remaining 50%) , and inter-percentile subgroup comparisons of the healthcare expenditure, medical insurance reimbursements, health service utilization, and population features were performed.

Both healthcare expenditures and medical insurance reimbursements were highly concentrated in each group of T2DM patients: the healthcare expenditure of patients with URBMI in subgroups 1 and 2 accounted for 66.12% of the total healthcare expenditures, and medical insurance reimbursements of those with URBMI in subgroups 1, 2 and 3 accounted for 82.97% of the total medical insurance reimbursements. The healthcare expenditure of patients with UEBMI in subgroups 1 and 2 occupied 43.12% of the total healthcare expenditure, and medical insurance reimbursements of those with UEBMI in subgroups 1, 2 and 3 occupied 61.62% of the total medical insurance reimbursements. Gender, age and the perferred medical institutions were significantly different between patients in subgroups 1 and 2 and those in other three subgroups, and between patients in subgroups 1, 2, 3, and 4, and those in subgroup 5 regardless of the type of medical insurance (URBMI or UEBMI) (P<0.05) .

The healthcare expenditures and medical insurance reimbursements in insured T2DM patients were highly concentrated. In particular, the level of concentration of medical insurance reimbursements in those with URBMI was higher than that of those with UEBMI. The high concentration of healthcare expenditures indicates that T2DM patients with high healthcare expenditures may have excessive medical utilization and moral risk. Policy effort should be paid to the reimbursements level of those with low-to-moderate healthcare expenditures, and to improve their access to healthcare services.

过度医疗和医疗服务未利用均影响医疗服务利用的公平性，研究慢性病人群医疗支出集中性，分析高医疗支出和低医疗支出患者的人群特征可以反映基本医疗保障制度的公平性。

了解基本医疗保险制度下2型糖尿病患者医疗支出的集中性。

于2019年7月从江苏省某市医保中心信息系统2017年医保数据中，抽取参加基本医疗保险且第一诊断为2型糖尿病患者的数据资料进行分析，最终纳入参加城镇居民基本医疗保险（简称居民医保）者24 107例、参加城镇职工基本医疗保险（简称职工医保）者109 265例。将不同医保参保患者按照医疗支出高低排序，并分为前1%、前>1%~5%、前>5%~10%、前>10%~50%、余下50%的5分位组，分析不同分位组患者的医疗支出、医保补偿、卫生服务利用情况及人群特征。

2型糖尿病患者的医疗总费用和医保补偿费用均具有高度集中性：在参加居民医保的患者中，前5%分位患者的医疗支出占总医疗支出的66.12%，前10%分位患者的医保补偿费用占全部补偿费用的82.97%；在参加职工医保的患者中，前5%分位患者的医疗支出占总医疗支出的43.12%，前10%分位患者的医保补偿费用占总医保补充费用的61.62%。无论是居民医保还是职工医保，前5%分位与其余95%分位参保患者、前50%分位和后50%分位患者的性别、年龄、就诊医疗机构级别比较，差异均有统计学意义（P<0.05）。

2型糖尿病患者的医疗总费用和医保补偿费用均具有高度的集中性，且居民医保患者医保补偿费用的集中性高于职工医保患者。医疗支出的高度集中性说明现行基本医保制度下高费用段2型糖尿病患者可能存在过度就医、道德风险等问题。同时，应关注2型糖尿病患者中低医疗支出人群的医疗保障，提高卫生服务可及性。