| Objective Recent years, some scholars have proposed that the current diagnostic criteriafor diabetes, fasting glucose7mmol L is not a sensitive early screening for diabetes, thisstudy aims to explore a reasonable cut-off point for fasting glucose screening.Method From2007to2013, a total of5,759patients (25to75years old,3,417men and2,342women) who accepted75g orally glucose tolerance test (OGTT) in Kailuan generalhospital affiliated of Hebei united university were evaluated in our study, including theinitial outpatients, in-patients and healthy population. The average age of the cases was52.12±10.53years. All subjects have underwent a standard OGTT test (the carbohydrateintake was no less than200g/day three days before the test, no acute complicationsoccurred before the test, after fasting8~10h before the test, all the patients take75gglucose), and the venous plasma glucose were measured in0h,0.5h,1h,2h and3h. Thevenous plasma glucose (PG2h)≥11.1mmol/L2h after OGTT were as the newlydiagnosed diabetic group (3,915cases,2,289men and1,626women, with an average ageof52.76±10.43years old). While the cases whose PG2h＜11.1mmol/L were the non-diabetic group (1,844cases,1,128cases were male, female716cases, average age50.75±10.61years old).The carbohydrate intake was no less than200g/day three daysbefore the test, no acute complications occurred before the test, after fasting8to10hoursbefore the test, the venous blood (3ml) was taken in the morning from the patients’ elbow,and after venous plasma glucose has done, the blood sample was examed on everWednesday immediately. The measurement of OGTT test was hexokinase method, aJapanese HITACHI7600automatic biochemical analyzer was used in the test, thereagent was supplied by China Bio-Technology Co. Ltd. PG2h≥11.1mmol/L was thegold standard for the diagnosis of diabetes. The SPSS13.0software was used forstatistical analysis to explore the reasonable fasting glucose screening cut-off point ofdiabetes.Result1) After the study of frequency distribution of fasting blood glucose levels, wefound there are34.4%cases whose fasting blood glucose＜7.00mmol/L in the diabeticgroup, and the fasting blood glucose＜6.13mmol/L was approximately86.3%in the non-diabetic group, indicating that, in using the existing diagnostic criteria for screeningdiabetes,34.4%of the patients will be missed diagnosis.2) Fasting blood glucose levels will rise when diabetes occurs, the difference was statistically significant (P＜0.05).3)We found in the correlation analysis with the whole population that, fasting glucose hadno correlation with gender and age (r-values were0.001and-0.025respectively, P＞0.05); fasting glucose was significantly positively correlated with2-hour postprandialglucose (r-values:0.853, P＜0.05).4) In the diabetic group, the2-hour postprandialglucose was significantly positively correlated with fasting plasma glucose (r-value:0.793＞0.5, P＜0.05); age has a weak negative correlation with fasting plasma glucosevalues (r-value:-0.151＜0.5, P＜0.05); gender has no correlation with fasting glucosevalues (P＞0.05).5) In the non-diabetic group, the2-hour postprandial glucose, genderand age all has a weak negative correlation with fasting plasma glucose valuesrespectively (r-value：0.077,0.061and0.406, P＜0.05).6) A linear regression analysisin the whole population showed that, the strongest correlation was the fasting bloodglucose≥6.13mmol/L with the venous plasma glucose≥11.1mmol/L two hours afterOGTT (P＜0.0001). The optimal cut-off point was also for fasting glucose6.13mmol/Lthrough the receiver operating characteristic curve (ROC).7) After testing the sensitivityand specificity, we found that, in the specificity, fasting blood glucose≥6.13mmol/L isbetter than fasting plasma glucose≥5.60mmol/L (86.23%and69.96%, respectively),while the sensitivity of fasting blood glucose≥6.13mmol/L is better than fasting plasmaglucose≥7.00mmol/L and fasting glucose≥7.80mmol/L (81.97%,65.62%and53.23%,respectively). This suggests that the fasting plasma glucose≥7.0mmol/L is not asensitively cut-off point in early screening for diabetes.8) In evaluation of differentfasting blood glucose screening values, we found that, with the fasting glucose elevated,the positive predictive value increased gradually, while the negative predictive valuedecreased. When the fasting plasma glucose≥6.13mmol/L, the positive predictive valueis92.67%.Conclusion FPG≥6.13mmol/L is far superior in the sensitivity of screening for diabetesthan FPG≥7.0mmol/L, so that the rate of misdiagnosis decreased by16.35%, and theaccuracy of screening diabetes was92.67%, and it’s suitable for early screening fordiabetes as a fasting glucose cut-off point. |
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