Glucose challenge test screening for prediabetes and early diabetes

• Published in: Diabetic medicine Vol. 34; no. 5; pp. 716 - 724
• Main Authors: Jackson, S. L., Safo, S. E., Staimez, L. R., Olson, D. E., Narayan, K. M. V., Long, Q., Lipscomb, J., Rhee, M. K., Wilson, P. W. F., Tomolo, A. M., Phillips, L. S.
• Format: Journal Article
• Language: English
• Published: England Wiley Subscription Services, Inc 01-05-2017
• Subjects: Adult; Aged; Blood Glucose - analysis; Blood Glucose - metabolism; Cost-Benefit Analysis; Diabetes; Diabetes Mellitus, Type 2 - blood; Diabetes Mellitus, Type 2 - diagnosis; Early Diagnosis; Female; Glucose; Glucose - pharmacology; Glucose Tolerance Test - economics; Glucose Tolerance Test - methods; Hospital administration; Humans; Male; Mass Screening - economics; Mass Screening - methods; Middle Aged; Plasma; Prediabetic State - blood; Prediabetic State - diagnosis; Primary care; ROC Curve
• ISSN: 0742-3071; 1464-5491
• DOI: 10.1111/dme.13270

Aims
To test the hypothesis that a 50‐g oral glucose challenge test with 1‐h glucose measurement would have superior performance compared with other opportunistic screening methods.
Methods
In this prospective study in a Veterans Health Administration primary care clinic, the following test performances, measured by area under receiver‐operating characteristic curves, were compared: 50‐g oral glucose challenge test; random glucose; and HbA1c level, using a 75‐g oral glucose tolerance test as the ‘gold standard’.
Results
The study population was comprised of 1535 people (mean age 56 years, BMI 30.3 kg/m2, 94% men, 74% black). By oral glucose tolerance test criteria, diabetes was present in 10% and high‐risk prediabetes was present in 22% of participants. The plasma glucose challenge test provided area under receiver‐operating characteristic curves of 0.85 (95% CI 0.78–0.91) to detect diabetes and 0.76 (95% CI 0.72–0.80) to detect high‐risk dysglycaemia (diabetes or high‐risk prediabetes), while area under receiver‐operating characteristic curves for the capillary glucose challenge test were 0.82 (95% CI 0.75–0.89) and 0.73 (95% CI 0.69–0.77) for diabetes and high‐risk dysglycaemia, respectively. Random glucose performed less well [plasma: 0.76 (95% CI 0.69–0.82) and 0.66 (95% CI 0.62–0.71), respectively; capillary: 0.72 (95% CI 0.65–0.80) and 0.64 (95% CI 0.59–0.68), respectively], and HbA1c performed even less well [0.67 (95% CI 0.57–0.76) and 0.63 (95% CI 0.58–0.68), respectively]. The cost of identifying one case of high‐risk dysglycaemia with a plasma glucose challenge test would be $42 from a Veterans Health Administration perspective, and $55 from a US Medicare perspective.
Conclusions
Glucose challenge test screening, followed, if abnormal, by an oral glucose tolerance test, would be convenient and more accurate than other opportunistic tests. Use of glucose challenge test screening could improve management by permitting earlier therapy.
What's new?
Optimum screening procedures for diabetes and prediabetes are not established.
We tested the performance of a 50‐g oral glucose challenge test (GCT) with 1‐h glucose measurement against other common screening methods, including HbA1c and plasma and capillary random glucose, using the oral glucose tolerance test as the ‘gold standard’.
Our findings in a Veterans Health Administration primary care setting show that GCT screening for high‐risk prediabetes and early diabetes is more accurate and less expensive than alternative opportunistic methods.
Accordingly, a policy of systematic GCT screening could be a major opportunity to improve the health of veterans.