Metabolic syndrome and its single traits as risk factors for diabetes in people with impaired glucose tolerance: the STOP-NIDDM trial

The STOP-NIDDM trial was an international, double-blind, placebo-controlled randomised study in people with impaired glucose tolerance (IGT). They were treated with an alpha-glucosidase inhibitor, acarbose, to prevent diabetes; the overall number needed to treat (NNT) was 11. In a secondary analysis, we considered the impact of single traits and overall metabolic syndrome (MetS) respectively on risk of diabetes and NNT respectively. In all, there were 1,368 patients. They were followed up for 3.3 years, and the prevalence of MetS was 61%. Multivariate analysis revealed treatment group 2-hour (post-challenge) plasma glucose, glycosylated haemoglobin (HbA(1C)), triglycerides and leukocyte count as independent predictors. The annual incidence of diabetes in the placebo group with MetS was 18.7% vs. 11.2% in patients without MetS; the corresponding figures in the acarbose group were 13.5% and 9.4%, respectively. The NNT in patients was 5.8 in patients with MetS and 16.5 in those without Mets. In conclusion, most single traits and overall MetS label a very high-risk group in people with IGT. People with MetS reach a NNT to prevent development of new diabetes with acarbose of 5.8.