occur over time during TZD treatment. Patients with type 2 diabetes who have significant underlying asymptomatic heart disease may also be prescribed these drugs, even though their safety in such patients has not been fully established. The package inserts for both rosiglitazone and pioglitazone indicate that patients with more advanced heart disease (class III or IV) were excluded in premarketing clinical trials, and hence, these drugs are not recommended in such patients. At present, there are no guidelines on the use of TZDs in patients with diabetes who have any degree of heart disease or for those already on a TZD who develop CHF. Because edema is a more frequent side effect of TZD therapy and by itself is often a perplexing clinical dilemma with multiple causes, 14 clinicians may need guidance when edema (or unexpected weight gain) is encountered in a patient on a TZD. For these reasons, the American Diabetes Association and the American Heart Association assembled a workgroup to evaluate the use of TZDs in patients with preexisting heart disease and in those who develop edema or unexpected weight gain during the course of TZD therapy. This Statement is a summary of the workgroup’s findings and recommendations.