Risk factor assessment for new onset diabetes: literature review

Metabolic syndrome (MS), typified by hypertension, abdominal obesity, dyslipidaemia and impaired glucose metabolism, is a precursor of type 2 diabetes. Thiazide diuretics (TD) and beta-blockers are associated with increased risk of diabetes in patients with hypertension; however, the role of these agents in development of diabetes in MS patients is unknown. We reviewed the literature regarding risk factors for diabetes development and compared this with data from the Study of Trandolapril/Verapamil SR And Insulin Resistance (STAR), which investigated the effects of two fixed-dose combinations (FDCs) [trandolapril/verapamil SR and losartan/hydrochlorothiazide (L/H)] on glucose control and new diabetes in MS patients. In STAR, logistic regression modelling identified haemoglobin A1c [odds ratio (OR) 4.21 per 1% increment; p = 0.003), L/H treatment (OR 4.04; p = 0.002) and 2-h oral glucose tolerance test glucose levels (OR 1.39 per 10 mg/dl increments; p < 0.001) as baseline predictors of diabetes. These data support prior analyses and suggest that choice of antihypertensive agent is important. Patients with MS may be at lower risk of diabetes when using a FDC calcium channel blocker + angiotensin-converting enzyme inhibitor compared with an angiotensin receptor blocker + TD.