Profound defects in β-cell function in screen-detected type 2 diabetes are not improved with glucose-lowering treatment in the Early Diabetes Intervention Program (EDIP)

Abstract

Background: Few studies have measured the ability of interventions to affect declining β-cell function in screen-detected type 2 diabetes. The Early Diabetes Intervention Programme (ClinicalTrials.gov NCT01470937) was a randomized study based on the hypothesis that improving postprandial glucose excursions with acarbose would slow the progression of fasting hyperglycaemia in screen-detected type 2 diabetes. In the Early Diabetes Intervention Programme, the effect of acarbose plus lifestyle advice on progression of fasting hyperglycaemia over a 5-year period was not greater than that of placebo. However, there was an early glucose-lowering effect of the trial. The objective of the current secondary analysis was to describe β-cell function changes in response to glucose lowering.

Methods: Participants were overweight adult subjects with screen-detected type 2 diabetes. β-cell function was measured using hyperglycaemic clamps and oral glucose tolerance testing. The primary outcome was the change in β-cell function from baseline to year 1, the time point where the maximal glucose-lowering effect was seen.

Results: At baseline, participants exhibited markedly impaired first-phase insulin response. Despite significant reductions in weight, fasting plasma glucose (PG) and 2-h PG, there was no clinically significant improvement in the first-phase insulin response. Late-phase insulin responses declined despite beneficial glycaemic effects of interventions.

Conclusions: Insulin secretion is already severely impaired in early, screen-detected type 2 diabetes. Effective glucose-lowering intervention with acarbose was not sufficient to improve insulin secretion or halt the decline of β-cell function.

Keywords: acarbose; hyperglycaemic clamp; insulin; obesity; oral glucose tolerance test.

Copyright © 2014 John Wiley & Sons, Ltd.

Figures

Figure 1

Glucose and insulin excursions in response to OGTT and hyperglycemic clamp testing at baseline (solid squares), after 1 year of treatment (open squares), and after 2 years of treatment (open circles). Change in OGTT FPG, 2-hr PG, and 2-hr insulin values from baseline to year 1, p

Figure 2

Measures of first-phase insulin secretion adjusted for insulin sensitivity (oDI and cDI) and second-phase insulin secretion (AUCins and phase 2 insulin) by treatment group during treatment. P values indicate comparisons across 1 or 2 years of intervention, as indicated by the horizontal bars; in all instances there was no significant treatment-specific effect.