Diabetic/cardiac patients can up your mortality stats
Regimens increase risk threefold after angioplasty
Keep a close eye on your cardiac patients with diabetes. They could negatively impact your mortality stats as well as your bottom line.
A recent clinical trial has shown that oral sulfonylurea drugs increase mortality risk following angioplasty.1 Previous laboratory tests have shown that the diabetes drugs have potentially adverse cardiovascular effects, including impairment of the heart’s ability to handle injury and of the capacity of blood vessels to relax.
The clinical implications of this study are uncertain — "the data are more provocative than definitive," says Kirk N. Garratt, MD. The Mayo Clinic (Rochester, MN) investigator compared the outcomes of 67 diabetic patients taking sulfonylurea drugs with those of 118 diabetic patients not taking the drugs. All have undergone direct balloon angioplasty. By the end of the hospital stay, the death rate was higher in the group taking the sulfonylurea drugs than in the non-sulfonylurea group (24% vs. 11%).
Biguanides are easier on the heart
After adjusting for baseline differences between the two groups, the Mayo investigators determined that sulfonylurea drugs increases the risk of death almost threefold. They suggest that a possible approach is to prescribe alternative drugs for angioplasty patients, such as biguanides, which appear to have less of a deleterious effect on the heart.
Adding to the troubles of your cardiac patients with diabetes, intensive insulin treatment results in weight gain and changes in lipid levels and blood pressure — factors that may increase the risk of coronary artery disease (CAD) and add to your facilities’ costs.
Investigators recently randomized 1,168 patients with Type 1 diabetes to either intensive — insulin — or conventional treatment and followed their progress for six years to determine the effects of weight gain on their blood fat levels and blood pressure.2
The participants were divided into four groups of weight gain for purposes of comparison — those whose weights remained stable; those who gained approximately 10 pounds; those who gained approximately 20 pounds; and those who gained approximately 40 pounds.
Patients in the intensive insulin group gained the most weight and had the highest body mass index and blood pressure as well as the highest cholesterol, triglyceride, and apolipoprotein B levels:
• body mass index 31 kg/m vs. 24 kg/m;
• blood pressure 120/77 mmHg vs. 113/73 mmHg;
• apolipoprotein B .89 g/L vs. .78 g/L;
• higher waist-to-hip ratio;
• higher LDL levels;
• lower HDL and apolipoprotein A-1 levels.
Changes from weight gain may up risk
The study authors conclude the changes in lipid and blood pressure levels that occur with the excessive weight gain (that often goes with intensive therapy) are similar to those seen in the insulin resistance syndrome, and may increase the risk of coronary artery disease in that subset of patients.
Ralph R. Hall, MD, at the University of Missouri-Kansas City School of Medicine commented that the second study findings regarding insulin therapy indicate there is not only a need to lower LDL levels in diabetic cardiac patients, but to alter the quality of lipoproteins.
Dense lipoproteins, he says, derive their atherogenic properties because of their low-binding affinity for LDL receptors, a decreased resistance to oxidative stress, and a prolonged plasma half-life.
What to do with Type 1 diabetics who have a tendency to gain weight? The statins decrease LDL, but do not alter their dense quality. Metformin, fibrates, troglitazone, and exercise affect the changes in lipoproteins that increase their size and affinity for LDL receptors, rendering them less atherogenic. Combining insulin with metformin or the fibrates may prevent unfavorable changes, Hall says.
References
1. Garratt KN, Brady PA, Hassinger NL, et al. Sulfonylurea drugs increase early mortality in patients with diabetes mellitus after direct angioplasty for acute myocardial infarction. JACC 1999; 33:119-124.
2. Purnell JQ, Hokanson JE, Marcovina SM, et al. Effect of excessive weight gain with intensive therapy of Type 1 diabetes on lipid levels and blood pressure. JAMA 1998; 280:140-146.
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