Random blood glucose: a robust risk factor for type 2 diabetes.

CONTEXT Although random blood glucose (RBG) values are common in clinical practice, the role of elevated RBG values as a risk factor for type 2 diabetes is not well described. OBJECTIVE This study aimed to examine nondiagnostic, RBG values as a risk factor for type 2 diabetes DESIGN This was a cross-sectional study of National Health and Nutrition Examination Surveys (NHANES) participants (2005-2010). PARTICIPANTS Nonfasting NHANES participants (n = 13 792) without diagnosed diabetes were included. PRIMARY OUTCOME The primary outcome was glycemic status (normal glycemia, undiagnosed prediabetes, or undiagnosed diabetes) using hemoglobin HbA1C as the criterion standard. ANALYSIS Multinomial logistic regression examined associations between diabetes risk factors and RBG values according to glycemic status. Associations between current U.S. screening strategies and a hypothetical RBG screening strategy with undiagnosed diabetes were examined. RESULTS In unadjusted analyses, a single RBG ≥ 100 mg/dL (5.6 mmol/L) was more strongly associated with undiagnosed diabetes than any single risk factor (odds ratio [OR], 31.2; 95% confidence interval [CI], 21.3-45.5) and remained strongly associated with undiagnosed diabetes (OR, 20.4; 95% CI, 14.0-29.6) after adjustment for traditional diabetes risk factors. Using RBG < 100 mg/dL as a reference, the adjusted odds of undiagnosed diabetes increased significantly as RBG increased. RBG 100-119 mg/dL (OR 7.1; 95% CI 4.4-11.4); RBG 120-139 mg/dL (OR 30.3; 95% CI 20.0-46.0); RBG ≥ 140 mg/dL (OR 256; 95% CI 150.0-436.9). As a hypothetical screening strategy, an elevated RBG was more strongly associated with undiagnosed diabetes than current United States Preventative Services Task Force guidelines (hypertension alone; P < .0001) and similar to American Diabetes Association guidelines (P = .12). CONCLUSIONS A single RBG ≥ 100 mg/dL is more strongly associated with undiagnosed diabetes than traditional risk factors. Abnormal RBG values are a risk factor for diabetes and should be considered in screening guidelines.