October 21, 2016
2 min read

Glucose challenge test accurate, convenient in primary care setting

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Glucose challenge test screening, paired with oral glucose tolerance testing where appropriate, is less expensive and more accurate than other opportunistic tests for diabetes and prediabetes, data from a prospective study show.

Detection of diabetes early in the natural history of the disease is critical for preventive management with lifestyle change or medication, and the U.S. Preventive Services Task Force has created recommendations for systematic screening,” Sandra L. Jackson, PhD, of the Atlanta VA Medical Center in Decatur, Georgia, and Emory University in Atlanta, and colleagues wrote. “In the present study, we investigated whether the glucose challenge test would be an accurate, convenient and inexpensive screen in high-risk participants in a primary care setting.”

Researchers studied data from 1,535 patients in a Veterans Health Administration primary care clinic to compare the performance of oral glucose challenge, random glucose testing and HbA1c level testing with glucose tolerance testing. Median age was 56 years, 94% of patients were men, and 74% were black. Glucose tolerance testing indicated 10% had diabetes and 22% had high-risk prediabetes.

The area under receiver-operating characteristic curve (AUC) to detect diabetes was 0.85 (95% CI, 0.78-0.91) for the plasma glucose challenge test and 0.82 (95% CI, 0.75-0.89) for the capillary glucose challenge test. To detect high-risk dysglycemia, AUC was 0.76 (95% CI, 0.72-0.80) for the plasma glucose challenge and 0.73 (95% CI, 0.69-0.77) for the capillary glucose challenge.

Plasma glucose challenge testing outperformed HbA1c testing, random plasma glucose testing and random capillary glucose testing for the detection of both diabetes and high-risk dysglycemia (P < .05). Additionally, capillary glucose challenge testing was more accurate than HbA1c and random capillary glucose testing to detect diabetes and high-risk dysglycemia (P < .05), the researchers reported.

In terms of cost, Jackson and colleagues estimated that each case of dysglycemia detected via plasma glucose challenge would cost Veterans Affairs $42 and Medicare $55.

“A two-step screening approach, consisting of a 50-g glucose challenge test followed, if positive, by an oral glucose tolerance test, has long been a standard of care for gestational diabetes screening,” Jackson and colleagues wrote. “It is possible that a similar approach would be beneficial in a general population setting or among high-risk populations, such as in the VA health system. Further studies could investigate patient health and health care system impacts of such a strategy.” – by Andy Polhamus

Disclosure: Jackson reports receiving support from Amylin outside of the submitted work. Please see the full study for a complete list of all other authors’ relevant financial disclosures.