One‐hour post‐load plasma glucose level during the OGTT predicts mortality: observations from the Israel Study of Glucose Intolerance, Obesity and Hypertension

Abstract

The relationship between 1- and 2 h glucose levels following an oral glucose tolerance test (OGTT) and long-term mortality was evaluated.Over a 33 year period, 2138 individuals were followed for all-cause mortality. Fasting and post-OGTT glucose parameters categorized the cohort according to baseline glycaemic status. Four categories were established according to 1- and 2 h glucose levels (in mg/dl): group A = 1 h ≤ 155 and 2 h < 140; group B = 1 h > 155 and 2 h < 140; group C = 1 h ≤ 155 and 2 h = 140-199 (impaired glucose tolerance); group D = 1 h > 155 and 2 h = 140-199 (impaired glucose tolerance). Individuals with diabetes at baseline were excluded from the cohort.By August 2013, 51% of the study cohort had died. The worst prognosis occurred in group D (73.8%), followed by groups C (67.5% mortality), B and A (57.9% and 41.6%, respectively). When the 2 h glucose value is 'normal' (155mg/dl is an important predictor of mortality (28% increased risk) compared with group A, controlling for sex, age, smoking, BMI, systolic and diastolic blood pressures. A gradual increased hazard for mortality was seen by study group(hazard ratio = 1.28, 1.60 and 1.76, for groups B, C and D, respectively; group A = reference).A 1 h glucose value > 155 mg/dl predicts mortality even when the 2 h level is < 140 mg/dl. However, when the 2 h level is in the impaired glucose tolerance range, the hazard for mortality rises significantly independent of the 1 h value. Individuals at risk for developing diabetes could be identified earlier using the 1 h threshold value of 155 mg/dl, which could avert progression to diabetes and increased mortality. This article is protected by copyright. All rights reserved.