The 'Old' Anti-Diabetic Agents: A Systematic Inventory.

An array of oral agents is available for the treatment of hyperglycaemia in type 2 diabetes. This systematic inventory focuses on 'old' oral agents, including metformin, sulfonylureas (SUs), thiazolidinediones, alpha glucosidase inhibitors, and meglitinides. Twelve meta-analyses and six randomized controlled trials that used patient-relevant outcomes as primary endpoints were critically reviewed. Guidelines recommend the use of metformin or an SU as the first-line pharmacotherapeutic options. Beneficial effects of metformin have been demonstrated for 'any diabetes-related endpoint' and 'all-cause mortality' in small study groups of overweight and obese patients with newly manifested type 2 diabetes. Various SU agents are available, for which a class effect has clearly been disproven. Beneficial effects have only been demonstrated for glyburide in preventing microvascular complications. Thiazolidinediones have been withdrawn from the markets in some countries. Meta-analyses found an increased coronary risk for rosiglitazone. The benefit-to-risk ratios of alpha glucosidase inhibitors and meglitinides regarding hard endpoints remain uncertain. Diabetes treatment is complex and individualised. We identified several studies focusing on the efficacy of treatment policies rather than on single drug effects. However, as long as the efficacy of single agents regarding hard clinical endpoints is unclear, interpretation of study results on treatment policies remains speculative.