Islet β-cell function preservation by different anti-diabetic treatments in Chinese elderly patients with type 2 diabetes mellitus

BACKGROUND The preservation of islet beta-cell function in elderly patients with type 2 diabetes mellitus (T2DM) is a top priority for diabetic control. AIM To assess the preservation of islet beta-cell function among elderly Chinese patients with T2DM after different anti-diabetic treatments. METHODS In this longitudinal observational study, elderly patients with T2DM treated with insulin, oral antidiabetic drugs or a combination of both were enrolled to disclose their islet beta-cell function between baseline and follow-up. Islet beta-cell function was determined by the plasma Homeostasis Model for beta-cell function (HOMA-beta), C-peptide and area under the curve (AUC) based on oral glucose tolerance test. Changes in beta-cell function (decrement or increment from baseline) between different therapy groups were the outcomes. RESULTS In total, 745 elderly patients (>= 60 years) with T2DM [insulin monotherapy, n = 105; oral anti-diabetic drugs (OAD) monotherapy, n = 321; insulin plus OAD, n = 319] had their baseline and follow-up beta-cell function assessed during a median observation period of 4.5 years (range, 3.0-7.2 years). Overall, islet beta-cell function (HOMA-beta, fasting C-peptide, fasting insulin, AU(Cc-pep), AUC(ins), AUC(c-pep)/AUC(glu), AUC(ins)/AUC(glu)) consistently deteriorated over time regardless of the three different antidiabetic treatments. No statistical differences in decrement were observed among the three groups regarding the islet beta-cell function indices. All three groups showed an increased ratio of delayed insulin secretion response after 4.5 years of observation. CONCLUSION In Chinese elderly patients with T2DM, islet beta-cell function progressively declines regardless of insulin supplement or insulin plus OAD treatments.