Impaired fasting plasma glucose and long-term cardiovascular risk: still a foggy relationship

Abstract

This editorial refers to ‘Fasting plasma glucose in non-diabetic participants and the risk for incident cardiovascular events, diabetes, and mortality: results from WOSCOPS 15-year follow-up’[†][1], by D. Preiss et al. , on page 1230. Current definitions of diabetes1–3 all include the finding of an elevated fasting plasma glucose ≥7.0 mmol/L (126 mg/dL). In the World Health Organization (WHO) definitions diabetes can also be diagnosed in the presence of an elevated (≥11.1 mmol/L; 200 mg/dL) 2 h plasma glucose after an oral glucose tolerance test (OGTT).1 The National Diabetes Data Group4 and the WHO5 coined the term impaired glucose tolerance (IGT), an intermediate category between normal glucose tolerance and diabetes. The American Diabetes Association (ADA)2 and the WHO Consultation6 proposed some changes to the diagnostic criteria for diabetes and introduced a new category called impaired fasting glucose/glycaemia (IFG). The ADA more recently decreased the lower threshold for IFG from 6.1 to 5.6 mmol/L,3 but this has been criticized7,8 and has not yet been adopted by the WHO expert group that rather recommended to keep the previous cut-off points as shown in the WHO consultation report in 1999.6 These criteria were reviewed and retained by a new WHO expert group in 2005. Much of the dispute revolves around the prognostic implications of IFG. In other words, all experts agree that elevated plasma glucose above the currently agreed threshold levels to define diabetes carries an important prognostic implication,9,10 but what about lower levels? Fasting blood glucose is closely linked to an increased prevalence of microvascular complications—nephropathy, neuropathy, and retinopathy—this last probably the easiest to diagnose and a close correlate of hyperglycaemia.1–3,11 Originally thought to be negligible for ‘below-threshold’ levels,3,11 more … *Corresponding author. Tel: +39 0871 41512, Fax: +39 0871 402817, Email: rdecater{at}unich.it [1]: #fn-2