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Mixed-meal tolerance, arginine stimulation tests reproducible
Standardized mixed-meal tolerance and arginine stimulation tests are useful for providing measurements of beta-cell function that are reproducible and complementary, according to data from a recently published study.
“The ability to simply and reproducibly test [beta-cell function] is critical,” Sudha S. Shankar, MD, of Lilly Research Laboratories, Indianapolis, and colleagues wrote. “Quantification of [beta-cell function] would enable evaluation of interventions tailored to specific functional beta-cell defects in multiple populations, as well as their potential to alter disease progression.”
The researchers administered mixed-meal tolerance and arginine stimulation tests to 62 participants with obesity, 23 of whom had normal glucose tolerance. Of those who did not have normal tolerance, 17 had prediabetes and 22 had type 2 diabetes. Each participant underwent both tests twice, as well as one frequently sampled IV glucose tolerance test.
Compared with patients with normal glucose tolerance and those with prediabetes, insulin secretion was more than 86% lower among patients with type 2 diabetes, according to results of the mixed-meal tolerance test (P < .0001). Additionally, insulin sensitivity among patients with type 2 diabetes was 78% and 52% lower than patients with normal glucose and prediabetes (P < .001).
Reproducibility was “generally good” for the mixed-meal tolerance test, researchers wrote, having intraclass correlation coefficients between 0.3 and 0.8. The researchers described reproducibility for the arginine stimulation test as “very good,” with intraclass correlation coefficient values greater than 0.8, and concluded that both tests were useful for “large, longitudinal intervention studies.” Researchers added that both tests are simple enough to be administered at most clinical centers.
“We report that the [mixed-meal tolerance test] and [arginine stimulation test] are able to detect differences in [beta-cell function] across the metabolic spectrum,” the researchers wrote. “It should be noted that despite these tests having been in use for quite some time, this is the first report of within- and between-subject variability for outcome parameters from the standardized [mixed-meal tolerance test] and [arginine stimulation test], especially in subjects across the metabolic spectrum.” – by Andy Polhamus
Disclosure: Shankar reports being an employee and shareholder of Eli Lilly. Please see the full study for a list of all authors’ relevant financial disclosures.