Intensive insulin improved MI survival for patients with diabetes

Intensive insulin treatment was associated with an extra 2.3 years of survival after MI in patients with diabetes, according to new findings from the DIGAMI 1 trial.

However, the effect may be due in part to the age of the study, which was initiated at a time when treatments for glycemic control, hypertension and hyperlipidemia were fewer and less effective, according to the researchers.

The DIGAMI 1 trial included 620 patients hospitalized for MI with previously diagnosed diabetes or with blood glucose concentrations >11 mmol/L between 1990 and 1993. One group (n=306) was randomly assigned intensified insulin-based glycemic control, and received an insulin-glucose infusion for at least 24 hours followed by subcutaneous insulin four times daily for at least 3 months. The other group (n=314) was randomly assigned standard care and did not receive insulin unless decided by the attending physician.

The primary outcome was mortality. Follow-up was until death or Dec. 31, 2011. Mean follow-up was 7.3 years and no patients were lost to follow-up.

Survival difference

During follow-up, 89% of patients in the intensified-insulin group and 91% of patients in the control group died, according to Viveca Ritsinger, MD, of Karolinska University Hospital, Stockholm, Sweden, and colleagues.

The median survival time in the intensified-insulin group was 7 years (interquartile range, 1.8-12.4), while the median survival time in the control group was 4.7 years (interquartile range, 1-11.4) (HR=0.83; 95% CI, 0.7-0.98).

“The effect of the intensified glycemic control was apparent during 8 years after randomization, increasing survival by 2.3 years,” Ritsinger and colleagues wrote.

Because fewer antihypertensive and lipid-lowering drugs were available at baseline in the early 90s compared with today, the effect of intensive insulin treatment might not be quite so dramatic if a study were begun today, but it might still have a benefit, they wrote.

“Although the effect of glucose lowering might be less apparent with presently available, more effective lipid-lowering and [BP]-lowering drugs, improved glycemic control might still be important for longevity after acute [MI],” they wrote.

Practice should not be changed

In a related editorial, Denise E. Bonds, MD, MPH, from the National Heart, Lung and Blood Institute, noted that the findings differ from more recent studies which found no improvement or higher mortality in those randomized to intensive insulin therapy and that doctors should not change clinical practice based on them.

“Instead, the value of the paper lies in its history,” she wrote. “First, it points to the benefit of good glucose control even when other factors such as lipids or [BP] cannot be or are not modified. Second, and perhaps most importantly, it provides an important reminder of how quickly medicine is advancing.”

For more information:

Bonds DE. Lancet Diabetes Endocrinol. 2014;doi:10.1016/S2213-8587(14)70106-8.

Ritsinger V. Lancet Diabetes Endocrinol. 2014;doi:10.1016/S2213-8587(14)70088-9.

Disclosure: The original DIGAMI trial was funded in part by Sanofi. One researcher is an employee of Hoffman-La Roche and another reports consulting income from AstraZeneca, Pfizer and Roche. The other researchers and Bonds report no relevant financial disclosures.