Prevention of type 2 diabetes mellitus with angiotensin-converting-enzyme inhibitors.

PURPOSE: The physiological and clinical data for using angiotensin-converting- enzyme (ACE) inhibitors to prevent new-onset type 2 diabetes mellitus are reviewed.
SUMMARY: ACE inhibitors have established their role in hypertension, primary and secondary prevention of cardiovascular events, and prevention of progression to and worsening of renal function. However, their ability to preserve pancreatic function and prevent new-onset diabetes is also coming to the forefront. Secondary analyses of large-scale clinical trials, such as the Captopril Prevention Project, the Heart Outcomes Prevention Evaluation, and the Studies of Left Ventricular Dysfunction trial, are revealing the potential benefits of these agents in diabetes prevention. However, the results of such studies have limited application because they are secondary analyses and, in some cases, were conducted 10 or more years after the original study. Enrollees were evaluated using different diagnostic guidelines for diabetes or not formally evaluated at all. Even in the most recent of the trials, the validity of the results is questionable because researchers coadministered a disease-modifying drug with the ACE inhibitor, potentially blunting the results. While intense lifestyle modifications are still superior in the prevention of new-onset diabetes, patients and providers will continue to investigate new options for preventing the progression of impaired fasting glucose to diabetes, though this delay does not correlate with a decrease in morbidity and mortality.
CONCLUSION: ACE inhibitors may preserve pancreatic function and prevent new-onset diabetes, especially for patients who are hypertensive with impaired glucose tolerance. Large studies investigating the effect of ACE inhibitors on the prevention of diabetes as a primary outcome are needed to determine the use for this indication.