OBJECTIVE: Methods to assess beta-cell function in clinical studies are limited. The aim of the current study was to compare a direct measure of insulin secretion with fasting surrogate markers in relation to glucose tolerance status. RESEARCH DESIGN AND METHODS: In 1,380 individuals from the Insulin Resistance Atherosclerosis Study, beta-cell function was assessed using a frequently sampled intravenous glucose tolerance test (first-phase insulin secretion; acute insulin response [AIR]), homeostasis model assessment of beta-cell function (HOMA-B), proinsulin levels, and the proinsulin-to-insulin ratio. Beta-cell function was cross-sectionally analyzed by glucose tolerance categories (normal glucose tolerance [NGT], n = 712; impaired glucose tolerance [IGT], n = 353; newly diagnosed diabetes by 2-h glucose from an oral glucose tolerance test [OGTT] [DM2h], n = 80; newly diagnosed diabetes by fasting glucose [DMf], n = 135; or newly diagnosed diabetes by fasting and 2-h glucose and established diabetes on diet/exercise only [DM], n = 100). RESULTS: In Spearman correlation analyses, proinsulin and the proinsulin-to-insulin ratio were only modestly inversely related to AIR (r values from -0.02 to -0.27), and AIR was strongly related to HOMA-B (r values 0.56 and 0.58). HOMA-B markedly underestimated the magnitude of the beta-cell defect across declining glucose tolerance, especially for IGT and new DM by OGTT compared with AIR. Analyses adjusting for insulin sensitivity showed that beta-cell function was compromised in IGT, DM2h, DMf, and DM, relative to NGT, by 13, 12, 59, and 62% (HOMA-B) and by as much as 40, 60, 80, and 75%, using AIR. CONCLUSIONS: Subjects with IGT and early-stage, asymptomatic type 2 diabetic patients have more pronounced beta-cell defects than previously estimated from epidemiological studies using homeostasis model assessment.
OBJECTIVE: Methods to assess beta-cell function in clinical studies are limited. The aim of the current study was to compare a direct measure of insulin secretion with fasting surrogate markers in relation to glucose tolerance status. RESEARCH DESIGN AND METHODS: In 1,380 individuals from the Insulin Resistance Atherosclerosis Study, beta-cell function was assessed using a frequently sampled intravenous glucose tolerance test (first-phase insulin secretion; acute insulin response [AIR]), homeostasis model assessment of beta-cell function (HOMA-B), proinsulin levels, and the proinsulin-to-insulin ratio. Beta-cell function was cross-sectionally analyzed by glucose tolerance categories (normal glucose tolerance [NGT], n = 712; impaired glucose tolerance [IGT], n = 353; newly diagnosed diabetes by 2-h glucose from an oral glucose tolerance test [OGTT] [DM2h], n = 80; newly diagnosed diabetes by fasting glucose [DMf], n = 135; or newly diagnosed diabetes by fasting and 2-h glucose and established diabetes on diet/exercise only [DM], n = 100). RESULTS: In Spearman correlation analyses, proinsulin and the proinsulin-to-insulin ratio were only modestly inversely related to AIR (r values from -0.02 to -0.27), and AIR was strongly related to HOMA-B (r values 0.56 and 0.58). HOMA-B markedly underestimated the magnitude of the beta-cell defect across declining glucose tolerance, especially for IGT and new DM by OGTT compared with AIR. Analyses adjusting for insulin sensitivity showed that beta-cell function was compromised in IGT, DM2h, DMf, and DM, relative to NGT, by 13, 12, 59, and 62% (HOMA-B) and by as much as 40, 60, 80, and 75%, using AIR. CONCLUSIONS: Subjects with IGT and early-stage, asymptomatic type 2 diabeticpatients have more pronounced beta-cell defects than previously estimated from epidemiological studies using homeostasis model assessment.
Authors: J M Luther; P Luo; M T Kreger; M Brissova; C Dai; T T Whitfield; H S Kim; D H Wasserman; A C Powers; N J Brown Journal: Diabetologia Date: 2011-04-26 Impact factor: 10.122
Authors: Kevin S C Hamming; Daniel Soliman; Nicola J Webster; Gavin J Searle; Laura C Matemisz; David A Liknes; Xiao-Qing Dai; Thomas Pulinilkunnil; Michael J Riedel; Jason R B Dyck; Patrick E Macdonald; Peter E Light Journal: Diabetes Date: 2010-04-22 Impact factor: 9.461
Authors: Myrlene A Staten; Michael P Stern; W Greg Miller; Michael W Steffes; Scott E Campbell Journal: Diabetes Care Date: 2010-01 Impact factor: 19.112