Outcome studies in type 2 diabetes

Outcome studies are used to measure clinically meaningful primary end points, such as mortality and cardiovascular morbidity. However, few outcome trials have been conducted exclusively in people with diabetes; the majority of conventional diabetes trials use surrogate end points that may or may not translate into clinical benefits. Our current knowledge of the effects of pharmacotherapies on cardiovascular risk in patients with diabetes has been gained from subgroups included in large-scale studies. Several trials with lipid-modifying, antiplatelet and/or antihypertensive therapy, for example the recent Collaborative AtoRvastatin Diabetes Study, have included sufficient numbers of patients with diabetes to indicate that effective management can reduce cardio vascular risk in this patient population. The United Kingdom Diabetes Study and the Diabetes Control and Complications Trial provide important, but inconclusive data on the impact of glucose-lowering therapy on the incidence of cardiovascular complications in diabetes. Thiazolidinediones have only become available during the past few years, thus their effects were not assessed in these landmark trials. Ongoing studies in diabetic populations at high risk for further macrovascular events, such as the PROspective pioglitAzone Clinical Trial In macroVascular Events, have been designed to assess the effect of thiazolidinediones on cardiovascular outcome in patients with diabetes and should help to reinforce the importance of broad-based treatment of the multiple metabolic risk factors for cardiovascular disease in people with diabetes.

This paper (based upon MEDLINE and EMBASE literature searches in the year range 1990-2005) reviews what we have learned from outcome studies up to the end of 2004 and looks at what we hope to learn from ongoing studies.