| Objective:We used the indirect method to establish and verify the reference interval of homocysteine(HCY)for serum sample in our laboratory.The method was used to establish the reference interval in this city and understand the distribution of HCY in healthy population in a quick way.We also explored the correlation between HCY and Diabetic Retinopathy(DR),and established the diagnostic range of HCY in the diagnosis of DR by drawing the Receiver Operating Characteristic Curve(ROC).In this way we want to provide reference for the diagnosis and treatment of clinical type 2 Diabetic retinopathy.Methods:The test data were stored in the Laboratory Information System(LIS)of our hospital from January 1,2016 to February 20,2020.Those data were used and screened according to the inclusion criteria and exclusion criteria by the Physical Examination System.The reference interval of serum HCY was established and verified after the analysis of the excluded reasons.And we used clinical data and laboratory test results which hospitalized patients with type 2 diabetes from January 1,2018 to 31 December 2019 to group the patients.The patients who with diagnosed type 2 diabetes and accompanied by DR were observation group,the patients who without DR were control group.Then we used statistical methods to study the correlation between HCY and DR and its diagnostic value on the DR.Results:Part I:(1)After we analyzed the reasons of exclusion in the initial screening of the physical examination,we found that for males,hyperuricemia(43.2%)was the most reason for aged 20-39 group who were excluded,followed by obesity(15.5%).In the 40 to 59 years old male group,the hyperuricemia(27.6%)was the highest reason,followed by hyperlipidemia(18.0%).which 24 cases were excluded.In the?60 years old male group the mainly reason was hypertension(23.8%),followed by atherosclerosis(20.8%),which 41 cases were not included.In the female group the thyroid dysfunction(31.1%)was the highest reason for females aged 20 to 39,followed by hyperuricemia(27.8%),which 8 cases were excluded.And in the 40 to 59 years old female group the most case was hyperlipidemia(26.0%),followed by thyroid dysfunction(23.6%),among which 13 cases were not included in the proportion.In the?60 years old female group,the mainly reason was hypertension(28.1%),followed by diabetes(21.1%),among which 21 cases were not included in the proportion.(2)HCY was correlated with gender and age.The reference interval established for the grouping were:for males,20-39 years old:?13.88 mol/L;40?59 years:?14.00 mol/L;?60 years:?14.53 mol/L;for females,20-39 years old:?11.80 mol/L;40?59 years:?12.50 mol/L;?60 years:?4.53 mol/L.After be proven.those data were applicable for the local laboratories.Part ?:Patients in the observation group(DR group)had significantly higher levels of HCY,HbA1c,FBG,postprandial blood glucose,uric acid and diabetes course than those in the control group(DM group),with statistically significant differences(P<0.05).Logistic multivariate regression analysis showed that HCY and HbAlc levels and the course of diabetes were still closely related to DR after excluding confounding factors(OR>1,P<0.05).Multivariate regression analysis of the same disease duration and years showed that HCY was still a risk factor for DR(OR>1,P<0.05).After the ROC curves of HCY,HbA1C,course of diabetes and combine these factor were drawn and analyzed,the diagnostic sensitivity of HCY was 62.55%,the specificity was 74.8%,the Youden index was 0.37,and the area under the curve(AUC)was 0.756(P<0.05).The diagnostic sensitivity of HbA1c was 64.72%,the specificity was 85.4%,the Youden index was 0.50,and the area under the curve(AUC)was 0.830(P<0.05).The diagnostic sensitivity of the disease course was 46.55%,the specificity was 74.6%,the Youden index was 0.21,and the area under the curve(AUC)was 0.640(P<0.05).The diagnostic sensitivity of the combine test was 74.9%,the specificity was 86.4%,the Youden index was 0.61,and the area under the curve(AUC)was 0.879(P<0.05).The diagnostic threshold corresponding to the maximum point of the Youden index was 14.8 mol/L for HCY,9.3%for HbA1c,and 6.5 years for disease course.Conclusions:The indirect method is a simple and feasible method to establish and validate the biological reference interval of the project when using big data.The initial screening of the included data by using multiple systems can improve the accuracy of the biological reference interval and has a good clinical application value.High HCY,HbA1c and long course of disease are risk factors for DR.They are closely related to the occurrence and development of DR,and have certain diagnostic value for DR,with medium diagnostic sensitivity and specificity.The reference value for diagnosis is:HCY:14.8 mol/L,HbA1c:9.3%,and course of disease:6.5 years. |
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