Thiazolidinedione Use, Fluid Retention, and Congestive Heart Failure

Diabetes is a chronic, progressively worsening disease associated with a variety of microvascular and macrovascular complications. Cardiovascular disease (CVD) is the main cause of death in these patients (1,2). During the past decade, numerous drugs have been introduced for the treatment of type 2 diabetes that, used in monotherapy or in combination therapy, are effective in lowering blood glucose to achieve glycemic goals and in reducing diabetes-related end-organ disease. Two such drugs, rosiglitazone and pioglitazone, belong to the class called thiazolidinediones (TZDs) (3). Troglitazone, the first agent of this class to be approved, was effective in controlling glycemia but was removed from the market because of serious liver toxicity. Both rosiglitazone and pioglitazone are indicated either as monotherapy or in combination with a sulfonylurea, metformin, or insulin when diet, exercise, and a single agent do not result in adequate glycemic control (4) (package insert Avandia rosiglitazone maleate; GlaxoSmithKline and Actos (5) pioglitazone hydrochloride; Takeda Pharmaceuticals). In addition to lowering blood glucose, both drugs may benefit cardiovascular parameters, such as lipids, blood pressure, inflammatory biomarkers, endothelial function, and fibrinolytic status (6,7). These beneficial effects of TZDs on glycemia and cardiovascular risk factors have made them attractive agents in patients with type 2 diabetes who are at high risk for CVD. There is a growing recognition, however, that edema can occur in patients treated with either drug. Because people with diabetes are at increased risk for CVD and many have preexisting heart disease, the edema that sometimes accompanies the use of a TZD can be cause for concern, as it may be a harbinger or sign of congestive heart failure (CHF). An analysis of Medicare beneficiaries hospitalized with the diagnosis of diabetes and CHF indicated that the number of these patients discharged on TZDs had increased from …