Glycated haemoglobin predicts progression to diabetes mellitus in Pima Indians with impaired glucose tolerance
Little, R.R.; England, J.D.; Wiedmeyer, H.M.; Madsen, R.W.; Pettitt, D.J.; Knowler, W.C.; Goldstein, D.E.
Diabetologia 37(3): 252-256
ISSN/ISBN: 0012-186X PMID: 8174838 DOI: 10.1007/bf00398051
Glycated haemoglobin could offer several practical advantages over the OGTT for assessing glucose metabolism. Initial cross-sectional studies (19831985) on 381 subjects (mostly Pima Indians) described the relationship between HbA-1c (a specific glycated Hb) and the OGTT. We performed follow-up OGTTs and HbA-1c measurements on 257 of these same subjects 1.6-6.1 years later. Subjects were again grouped according to both the result of the OGTT (normal, IGT or diabetes, by WHO criteria) and HbA-1c result (normal or elevated based on mean +- 1.96 SD of normal). Of 66 subjects with IGT at baseline, 47 (71%) had nor- mal HbA 1, and 19 (29%) had elevated HbA-1c. Twenty-six (39%) of these subjects had diabetes at follow-up. Of these subjects with IGT, a significantly greater percentage of subjects with elevated HbA-1c at baseline (68%) showed worsening to diabetes than those with a normal HbA-1c (28%); (chi-square= 7.8, df = 1, p lt 0.01). Thus, in subjects with IGT, glycated Hb may be a useful predictor of progression to diabetes.