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

J Clin Endocrinol Metab. 2015 Apr;100(4):1503-10. doi: 10.1210/jc.2014-4116. Epub 2015 Feb 4.


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.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Blood Glucose / analysis*
  • Cross-Sectional Studies
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / diagnosis*
  • Female
  • Glycated Hemoglobin A / analysis
  • Humans
  • Male
  • Mass Screening / methods
  • Middle Aged
  • Nutrition Surveys
  • Prediabetic State / blood
  • Prediabetic State / diagnosis
  • Predictive Value of Tests
  • Prognosis
  • Risk Factors


  • Blood Glucose
  • Glycated Hemoglobin A
  • hemoglobin A1c protein, human