Diagnosis of hyperglycemia in a cohort of Brazilian subjects: fasting plasma glucose- and oral glucose tolerance test-based glycemic status are associated with different profiles of insulin sensitivity and insulin secretion.

Impaired fasting glucose (IFG) and impaired glucose tolerance (IGT) represent intermediate states between normal fasting glucose (NFG) or normal glucose tolerance (NGT), respectively, and diabetes (1). The regulation of fasting and glucose concentrations after an oral glucose load is dependent on different physiological mechanisms (2), and current evidence suggests that IFG and IGT have different pathophysiologies (3,4). Measurement of fasting plasma glucose (FPG) is the most frequently used screening test for diabetes. However, the oral glucose tolerance test (OGTT) might be a preferable test because FPG underestimates the severity of glucose intolerance (5,6) and because IFG and IGT define two distinct populations with only partial overlap (5,7,8). The present study was undertaken to compare insulin sensitivity and insulin secretion profiles associated with different stages of hyperglycemia as assessed by FPG only or by FPG and 2-h plasma glucose during an OGTT.