STUDY

1. Randomized over 600 patients (mean age 68) with diabetes who had an acute MI to: 1) Standard treatment in the coronary care unit or 2) Standard treatment plus insulin-glucose infusion for at least 24 hours followed by multidose insulin treatment.
2. All had a blood glucose on admission of over 11 mmoL/L (200 mg/L).
3. The treatment group received an insulin-glucose infusion according to a predefined protocol for at least 24 hours followed by subcutaneous insulin 4 times daily for at least 3 months. [See references 15-17 p 1515 for details.]
4. Control patients did not receive any insulin unless clinically indicated.
5. Follow-up-3 1/2 years.
6. At randomization mean blood glucose was 15 mmoL/L (270 mg/L); HbA1c 8.0% with no difference between groups.
7. At 24 h mean glucose was 210 mg/dL (11.7 mmoL/L) in the control group vs 173 mg/dL( 9.6 mmol/L) in the treatment group; glucose at discharge 162 (9.0) vs 148 (8.2).

RESULTS

1. At 3 1/2 years, 33% of the treatment group died vs 44% of the controls. (Difference = 11%; NNT to prevent one death = 9)
2. The benefit was most pronounced in those who had no previous insulin treatment and those at low cardiovascular risk (age under 70, no congestive failure, no previous MI, no treatment with digitalis).
3. Survival curves separated after one year. This tended to increase with time.

DISCUSSION

1. A previous study by this group of investigators ( "Diabetes Mellitus, Insulin Glucose Infusion in Acute Myocardial Infarction —DIAGAMI study group) reported that mortality in one year in diabetic patients after an acute MI could be reduced by 30% with intensive treatment. This report extends the benefit to over 3 years.
2. Metabolic control is of utmost importance in macrovascular death.
3. Benefit was most evident in low risk patients without previous insulin treatment.
4. Previous primary prevention studies have reported that metabolic control reduces likelihood of future development of coronary heart disease in patients with non-insulin-dependent diabetes.

CONCLUSION
Insulin-glucose infusion followed by intensive subcutaneous insulin in diabetic patients with acute myocardial infarction improved long term survival. The effect continues for over 3 years. (NNT = 9.)
BMJ May 24, 1997; 314:1512-15 Original investigation from the DIAGAMI Group reported by Karolinska Hospital, Stockholm, Sweden.
An editorial in this issue (pp 1497-98 —"Managing Diabetes After Myocardial Infarction: Time for a more aggressive approach" comments: In diabetics, thrombolysis has been withheld because of vague fears of its impact on diabetic retinopathy, and beta-blockers have not been used because they alter the lipid profile or mask hypoglycemia. Both are minor considerations when set against mortality. ACE inhibitors, aspirin, and cholesterol-lowering drugs form part of more aggressive care. "Hopefully the findings of this present study do not flounder on a reluctance on the part of either patients or doctors to introduce insulin." RTJ