Exploration and Validation of the Performance of Hemoglobin A1c in Detecting Diabetes in Community-Dwellers With Hypertension.

backgroundDiabetes can complicate hypertension management by increasing the risk of cardiovascular disease (CVD) and all-cause mortality. Studies targeting diabetes detection in hypertensive individuals demonstrating an increased risk of diabetes are lacking. We aimed to assess the performance of hemoglobin A1c (HbA1c) and its cut-off point in detecting diabetes in the abovementioned population.

methodsData from 4,096 community-dwellers with hypertension but without known diabetes were obtained from the Study on Evaluation of iNnovated Screening tools and determInation of optimal diagnostic cut-off points for type 2 diaBetes in Chinese muLti-Ethnic (SENSIBLE) study; these data were randomly split into exploration (70% of the sample) and internal validation (the remaining 30%) datasets. The optimal HbA1c cut-off point was derived from the exploration dataset and externally validated using another dataset from 2,431 hypertensive individuals. The oral glucose tolerance test was considered the gold-standard for confirming diabetes.

resultsThe areas under the ROC curves for HbA1c to detect diabetes were 0.842, 0.832, and 0.829 for the exploration, internal validation, and external validation datasets, respectively. An optimal HbA1c cut-off point of 5.8% (40 mmol/mol) yielded a sensitivity of 76.2% and a specificity of 74.5%. Individuals who were not diagnosed as having diabetes by HbA1c at 5.8% (40 mmol/mol) had a lower 10-year CVD risk score than those diagnosed as having diabetes (P=0.01). HbA1c≤5.1% (32 mmol/mol) and ≥6.4% (46 mmol/mol) could indicate the absence and presence of diabetes, respectively.

conclusionsHbA1c could detect diabetes effectively in community-dwellers with hypertension.