Comparison of diagnostic screening methods for diabetes in patients with heart failure

The objective of the study was to compare screening performances of HbA1c, fasting plasma glucose (FPG), and two-hour plasma glucose (2hPG) in heart failure (HF) patients. We included 237 HF patients aged >20 years without history of diabetes, using National Health and Nutrition Examination Survey data (2005–2016). American Diabetes Association diabetes screening criteria were used: (1) HbA1c ≥6.5%, (2) FPG ≥126 mg/dL, and (3) 2hPG ≥200 mg/dL. Sensitivity, specificity, predictive values, and Receiver Operating Characteristic (ROC) curves for HbA1c and FPG were examined against reference methods. N = 50 patients (20.5%) met at least 1 of 3 clinical criteria for diabetes. 2hPG alone identified 70.5% of patients, whereas HbA1c alone identified only 27.0% of patients. Sensitivity and specificity using a HbA1c cutoff at ≥6.5% were 24.4% and 97.6%, respectively. The Youden's J statistic for HbA1c was maximized at 6.1%. The area under the ROC curve of HbA1c against 2hPG was significantly lower compared to FPG (0.79, 95% CI 0.70-0.88; 0.89, 95% CI 0.84-0.94, respectively; p = 0.04). Blood glucose criteria are more sensitive than HbA1c when screening HF patients for diabetes. Future studies should test performance of a HbA1c cutoff at 6.1% when FPG or 2hPG cannot be completed.