Results of these trials give health care providers useful and heartening information to share with patients at risk for diabetes. The challenge remains to find feasible and cost-efficient methods to identify people at risk and to deliver effective lifestyle interventions.

Findings from trials of pharmacologic agents such as metformin, acarbose, and troglitazone are encouraging; however, the ADA recommends that drug therapy should not be used routinely to prevent diabetes until more information regarding the cost-effectiveness of such intervention is known.

Results from trials that found a lower incidence of diabetes among those randomly assigned to angiotensin-converting enzyme inhibitors, statins, or hormone therapy are intriguing but must be viewed with caution because they are based on post hoc analyses. Because it is difficult to conduct randomized controlled trials of major operative procedures such as bariatric surgery, observational studies that compare surgical interventions for weight loss with traditional weight-loss management may be the best evidence available. These studies have the potential for healthy-person bias in that people who choose bariatric surgery may have other healthy behaviors that are often difficult to measure and control for; such behaviors could account for their lower incidence of diabetes.

Undeniably, the best test to diagnose those at high risk for diabetes is not yet known. New strategies that identify those with pre-diabetes and that overcome the limitations of the current tests, particularly the 2-hour post-challenge glucose test, are needed.