There is not enough evidence to sug- gest that HbA1c targets should be dif- ferent from the targets described above. Particularly relevant to patients with HF is that less stringent goals of HbA1c <7% may be more appropriate, particularly in patients with conditions that are difficult to control (hypoglycemia, adverse effects of medications, variable blood glucose). Antihyperglycemic Medications in Patients With HF and Diabetes Mellitus Metformin Randomized, clinical trials of metformin therapy, includ- ing a subset of the UKPDS 34 study182 and a trial of 390 diabetic patients receiving background insulin ther- have demonstrated metformin-associated reduc- tions in macrovascular events, including MI and all-cause mortality. A potential reduction in macrovascular events in patients with ischemic HF may improve outcomes in a high-risk population. However, no prospective stud- ies assessing the safety and efficacy of metformin in patients with HF have been published. A large number of observational data support its safety and potential benefit, but residual confounding may be present (ie, patients with advanced illness do not receive metfor- min). The American Diabetes Association Standards of Medical Care in Diabetes statement has specified, In patients with stable CHF, metformin may be used if re- nal function is normal but should be avoided in unstable or hospitalized patients with HF. 13 One of the concerns about the use of metformin in patients with HF is the potential risk of developing lactic acidosis, which may be particularly relevant in patients with renal disease. Current US prescribing guidelines state that metformin should not be used in men with a creatinine level 1.5 mg/dL and in women with a creatinine level 1.4 mg/dL because metformin is renally eliminated. The threshold of renal insufficiency at which to restrict metformin is controversial. 