2.1 Demographic analysis
2.1.1Data source and demographic analysis
The study used data from China Health and Retirement Longitudinal Survey (CHARLS) in 2015, which involved 150 counties and 450 communities (villages) in 28 provinces (autonomous regions and municipalities directly under the Central Government) in China, with a sample of 23,000 respondents from 12,400 households. The survey objects are mainly microdata of families and individuals aged 45 and above in China. The participants were interviewed face-to-face in their homes through computer-assisted personal interviewing (CAPI) technology.The CHARLS datasets can be downloaded at the CHARLS home page at http://charls. pku.edu.cn/en.
To study CRP as a screening tool for diabetes patients at high risk of complications in the community, we limited the sample to respondents who underwent physical examination in 2015, including 20,967 people, and screened patients from the subject sample who were required to meet the following conditions: Detailed data were collected via a standard questionnaire including completion of a complete questionnaire, participation in laboratory examinations, and demographic characteristics. A total of 216 subjects meet the criteria (Fig. 1), underwent serum C-reactive protein detection; Deleted data included no serum C-reactive protein test, heart disease, stroke, and nephropathy disease, and missing data.
2.1.2 Analysis Method
Eligible samples were filtered by using Excel and SPSS25.0 . Using stepwise confirmatory procedure. We relied on self-report diabetes data from each participant. In the present study, 216 eligible subjects were divided into two groups based on CRP≥3mg/L and < 3mg/L [15], including 60 CRP≥3mg/L patients and 156 CRP<3mg/L patients. Table 1 shows the baseline characteristics of patients in the two groups.
Table 1 Characteristic distribution of patients with CRP≥3mg/L and CRP < 3mg/L.
Characteristic
|
CRP≥3mg/L
(n=156)
|
CRP<3mg/L
(n=60)
|
t/X²
|
P-value
|
Age
|
57.88±9.9
|
60.06±10.6
|
1.434
|
>0.05
|
Gender,n(%)
Male
Female
|
58(37.2)
98(62.8)
|
24(40)
36(60)
|
0.146
|
>0.05
|
BMI,n(%)
<18.5
18.5-23.9
>23.9
|
1(0.6)
55(35.3)
100(64.1)
|
1(1.6)
19(31.7)
40(66.7)
|
0.699
|
>0.05
|
CRP serum C-reactive protein
2.2 Economic burden analyses
To keep the analysis concise and stable, the study only analyzed the cost of serum C-reactive proteins screening and direct medical cost to measure financial burden.
2.2.1 Design of health economy model
Patients were divided into an experimental group (CRP screening) and a control group (no CRP screening). According to the natural history Markov state transition model for diabetes (Fig.2), in this study, we analyzed the economic health feasibility of using CRP screening as a tool for high risk groups of diabetic complications patients in China community. In order to ensure correlation between the individual attributes , Tree Pro2019 software is used to establish Markov models. Six different health states were in the model: diabetes, stroke, myocardial infarction, diabetic nephropathy, diabetic foot, and death. At the end of the model (one year), an individual either transitions to a different health state or stays in the same one . The initial state assumes that the target patients entering the model are diabetes with no complications from heart disease, stroke , or nephropathy . Based on the average annual probability of transfer of various disease states in different health states (diabetes, multiple complications, death, etc.) , we calculated the distribution of the various health states throughout the next cycle (by year) (Fig.S1), as well as the value of the screening costs and direct medical expenditures of patients with different health states throughout this cycle. We compared the potential to reduce the economic burden of serum C-reactive protein as a routine screening method for community residents.
2.2.2 Model parameters
This cycle was combined with patients' average age and life expectancy at baseline to determine the total simulation time. The mean age of CHARLS2015 sample patients was 58.4 years, and based on the analysis of the China Statistical Yearbook [16],the average life expectancy of Chinese residents is projected to rise to 80.88 years by 2030, the simulation cycle for this model is therefore set to 20 years. According to the [17]2021 National Development and Statistics Bulletin of the People's Republic of China, we suggest using a discount rate of 5%, and choosing a discount rate in the range of 3%-8% for the sensitivity analysis. Information on the likelihood of metastasis among various medical conditions in patients with diabetes was obtained from the published literature (see TableS1).
2.2.3 Calculation of economic burden of disease
The cost of each diagnosis and treatment in the model was collected in 2003 [22] , and calculated according to the 2015 Consumer Price Index [23] , the cost of C-reactive protein screening was ¥10 per time [24]. The costs of each item are shown in TableS2.
According to Markov cost analysis, after 20 years, the cumulative cost of the experimental group is ¥109,849, the cumulative cost of the control group is ¥160,338, and the incremental cost is -¥50,488, indicating that the experimental group can reduce the economic burden (see TableS3).