YOU'RE CARING for a patient who's just had a myocardial infarction (MI). You note that she has a 10-year history of Type 2 diabetes and takes glimepiride (Amaryl), 4 mg every day. When you check her blood glucose level, it's 240 mg/dl. Previous readings ranged from 290 to 310 mg/dl. What research findings can you draw on to best support this patient's recovery?

Examining the evidence

Research shows that aggressive blood glucose control significantly reduces the risk of MI in patients with diabetes. Several recent studies should guide your practice decisions during your patient's recovery from an MI.

* In the Diabetes Mellitus Insulin-Glucose Infusion in Acute Myocardial Infarction study, intensive insulin treatment reduced both the 1-year mortality rate and the long-term all-cause mortality rate by 28% in patients with Type 1 and Type 2 diabetes who'd had an acute MI. Treatment involved an insulin-glucose infusion given for at least 24 hours, followed by a closely monitored multidose insulin regimen. Benefits were most pronounced in patients who hadn't previously been treated with insulin.

* The United Kingdom Prospective Diabetes Study, a clinical trial of optimal blood glucose and blood pressure control after diagnosis of Type 2 diabetes, showed that each 1% drop in hemoglobin A1C corresponded to a 14% to 16% reduction of risk for MI.

* Now in progress, the Action to Control Cardiovascular Risk in Diabetes study is a multicenter trial supported by the National Institutes of Health. Its purpose is to identify the best ways to lower the risk of cardiovascular disease in patients with Type 2 diabetes. For example, it will help to determine if lowering the A1C, low-density lipoprotein level, and systolic blood pressure prevents progression of cardiovascular disease in these patients. This is the first study to examine all three factors and to explore whether patients can feasibly keep A1C at 6.0 for a prolonged period (5 to 8 years).

What you learn from A1C

The A1C (also known as glycosylated hemoglobin, glycated hemoglobin, or glycohemoglobin) is an accurate, objective gauge of chronic glycemia in diabetes. You need to know your patient's A1C for two reasons: It indicates how successful her diet/exercise/medication regimen was before the MI, and it provides a baseline with which to evaluate progress in the future.

In most labs, the normal reference range is 4% to 6%. The goal for patients with diabetes is below 7%, which correlates to an average daily blood glucose below 170 mg/dl. In this case, your patient's A1C is 9%, which indicates that her average daily blood glucose level has been around 240 mg/dl. Both values are much higher than the goal for these indicators.

Because the physiologic stress of an MI raises blood glucose levels, maintaining her blood glucose levels in the normal range will be especially challenging during her recovery. After consulting with the endocrinologist and certified diabetes educator, you initiate an I.V. insulin infusion as ordered. Based on hourly bedside blood glucose checks, you titrate the rate to achieve a blood glucose level of less than 200 mg/dl, possibly less than 150 mg/dl, depending on the patient's condition and response to treatment. Later, she'll make the transition from an I.V. infusion to multiple daily S.C. injections.

Before discharge, her health care provider will assess her blood glucose readings and psychosocial situation to determine what insulin regimen or oral drug she should use at home. Teach her to see her health care provider regularly for ongoing care and stress the importance of maintaining her A1C at less than 7% to protect her health and prevent cardiovascular and other diabetic complications.

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