| Background: It was at the 2010 ADA's conference that HbAlc was officially confirmed as the diabetes diagnosis standard,when it would be greater than or equal to 6.5%.However,the current diabetes diagnosis standard in China is still based on the 1999-WHO criteria.Objective: This study aims to compare the diagnostic efficiency of using FPG,HbAlc and their combination to screen diabetes(DM)out of high-risk groups.It is also aimed at investigating and evaluating the best diagnostic threshold of HbAlc in screening type-2 diabetes.Methods: Relying on the Clinical Medicine Research Platform Construction and Promotion of the Early Screening and Control of Diabetes,a Shandong Science and Technology Demonstration Project(Project NO.: 2014kjhm0112),a cross-sectional survey was conducted among the high-risk groups of diabetes recruited in Jinan from May 2015 to February 2017.Detailed questionnaire,physical examination and laboratory examination were carried out among the experimental subjects,including FPG,HbAlc,TG,TC,LDL-C,HDL-C,ALT,AST,sUA and Cr.The subjects without diabetes history were examined using OGTT.Based on this,the study diagnosed the glucose metabolism of the experimental subjects and analyzed the prevalence of diabetes among the high-risk groups of diabetes.The receiver-operating characteristic curve(ROC)was applied to find out the best diagnostic threshold of HbAlc and to evaluate the diagnostic efficiency of FPG,HbAlc as well as their combination.Results: The study completed the survey of 2822 people in all.Ruling out those diagnosed as diabetes as well as those lacking important data for a total of 383 people,we eventually analyzed 2100 cases,including 827 men and 1273 women.The mean age of the samples was 53.01 years old.The results were as follows.(1)Using OGTT as the gold standard,the study diagnosed 279 patients with type-2 diabetes mellitus out of the high-risk group without diabetes,which accounts for 14.46% of the total sample size.(2)The number of IGR was 708,accounting for 33.71% of the total sample.Among the pre-diabetic subjects,the glucose tolerance decreased(IGT)accounted for 68.30% and the fasting glucose anomaly(IFG)accounted for 15.66%.(3)The number of NGR was 1113,accounting for 53.00% of the sample.(4)Among the NGR group,IGR group and DM group,the indices are on the rise,such as age,body mass index(BMI),waist circumference(wc),average mean systolic blood pressure(SBP),diastolic blood pressure(DBP),FPG,2h-PG,HbAlc,total cholesterol(TC),triglyceride(Tg)and low density lipoprotein cholesterol(LDL-C).However,high density lipoprotein cholesterol(HDL-C)showed a downward trend and there was no correlation between the glucose metabolism and the level of serum creatinine(Cr).(5)According to ROC,this study found out that the cut point of HbAlc was 6.1%.The area under ROC curve was 0.898.The 95% credibility interval was between 0.876 and 0.919.(6)Compared with the existing international standard of HbA1c?6.5%,the cut point of 6.1% we found obtained higher sensitivity but less specificity.The false positive rate and false negative rate were both lower than ADA tangency in the diagnosis of diabetes.Both the positive predictive value and the negative predictive value were higher than the HbAlc tangency recommended by ADA).(7)When only FPG was used to screen DM,the sensitivity value was 57.28%,the rate of missed diagnosis 42.72%,the negative predictive value 93.26% and the Jordan index 57.28%.Based on our experimental subjects and ROC,it was found that the best cut point was 6.4mmol/L for using FPG to predict OGTT diabetes.The area under ROC curve was 0.93.The 95% credibility interval was between 0.912 and 0.949.When FPG was over or equal to 6.7 mmol/L,the positive predictive value was 99%.When FPG was less than 4.8 mmol/L,the negative predictive value was 98.7%.(8)For the experimental subjects in this study,when only the standard of HbA1c?6.5% was used,the sensitivity value was 46.69%,the specificity 98.26%,the misdiagnosis rate 1.74%,the missed diagnosis rate 53.31%,the positive predictive value 81.98%,the negative predictive value 91.60% and the Jordan index 44.95%.When HbAlc was lower than 5.0%,the negative predictive value was 98.7%.(9)When combining FPG with HblAc,the study showed that the sensitivity value was 67.22%,the specificity 98.26%,the missed diagnosis rate 32.78% and the Jordan index 65.48%.192 patients could be diagnosed directly and 102 patients could not be diagnosed.Among the 1908 experimental subjects who couldn't be diagnosed directly,the number of the impaired fasting blood glucose was 537 and that of the normal fasting blood glucose was 1371(FPG<5.6mmol/L).Conclusion:(1)Based on the OGTT gold standard,the prevalence rate of newly diagnosed type 2 DM patients is 13.28% among the high-risk groups of diabetes in Jinan city.53.00% of the high-risk groups of diabetes have completely normal glucose metabolism state and 39.85 % of them have no idea of their abnormal metabolic state.Taking the low awareness rate into consideration,the prevalence situation of diabetes is not optimistic.(2)The diagnostic standard recommended by ADA(HbAlc?6.5%)is not suitable for the local population.According to ROC,this study found that the cut point was 6.1%,which is lower than the ADA standard,but similar to the value found in the relevant literature in China.(3)Neither FPG nor HbAlc can provide satisfactory screening efficiency when either of them is used individually.The reason is that the missed diagnosis rate was high.It seems that utilizing a combination method(HbA1c and FPG)for diabetes screening can diagnose and rule out more diabetes patients,making the screening of diabetes easy and operable.(1)Diabetes can be diagnosed when FPG is higher than or equal to ?7.0mmol/L or HbAlc is higher than or equal to 6.5%.(2)The patients have no diabetes when FBG is less than 4.8mmol/L or HbAlc is less than 5.0%.When FPG is less than 5.6mmol/L and HbAlc is between 5.5% and 5.0%,diabetes can also be ruled out directly.(3)When FPG is between 5.6 mmol/L and 6.9mmol/L and HbAlc is between 5.6% to 6.4%,OGTT needs to be done.(4)When IFG or HbAlc is between 5.6% and 6.4%,the more risk factors for reference,the higher possibility for having diabetes. |
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