Postprandial glucose control as important as fasting glucose

In the on going battle to lower glucose levels, researchers have a new weapon. "We now have evidence that shows very clearly that postprandial glucose elevations are a risk factor for cardiovascular disease," said Scott Drab, Pharm.D., CDE, BC-ADM, director of the University Diabetes Care Associates, a clinic in Greensburg, Pa., and assistant professor of pharmaceutical sciences at the University of Pittsburgh.

UDCA provides personalized diabetes care. Pharmacists work on a team with physicians, nurses, and dietitians where drug therapy is coordinated with diet, exercise, and blood sugar monitoring to get patients to target goals.

Postprandial glucose (PPG) is important for another reason, continued Drab. Because the glycosylated hemoglobin level (HbA1c or A1c) measures glycemic control over the preceding two to three months, it is a reflection of both fasting glucose and PPG. If PPG is ignored, A1c can still be elevated and patients may not reach their A1c goals.

"I prefer drugs that do not continually stimulate the pancreas," said Edelman. The rapid-on, rapid-off effect of the meglitinides is more like a nondiabetic person's physiology. Unfortunately, these new drugs are more expensive than the longer-acting sulfonylureas, and many third parties won't pay for them. "I think managed care has killed these drugs," he said.

According to Edelman, a similar fate has befallen the AGIs (alpha-glucosidase inhibitors), another class that includes acarbose (Precose, Bayer) and miglitol (Glyset, Bayer/Pfizer). These drugs slow the absorption of carbohydrates from the intestines, thereby reducing PPG. However, like the meglitinides, they are also more expensive than the sulfonylureas.

Drab said there may be another reason oral drugs for PPG have not been widely embraced. He explained that as a diabetes patient's pancreas begins to fail, the glucose level that rises first is postprandial. As the disease progresses, fasting glucose levels also rise. Unfortunately, most people are not diagnosed with diabetes until this latter stage. "By the time fasting blood glucose levels are elevated, drugs like Starlix or Prandin don't work that well," he said. At this point, most patients need a sulfonylurea. The meglitinides can't be combined with the sulfonylureas because both stimulate the pancreas, and effects are not additive.

The meglitinides can be used with other antidiabetic medications, though. Both nateglinide and repaglinide may be added to metformin or a thiazolidinedione (TZD) such as rosiglitazone (Avandia, GlaxoSmithKline), or pioglitazone (Actos, Lilly/Takeda). As for the AGIs, miglitol is approved for use with sulfonylureas. Acarbose is approved for combination therapy with metformin, sulfonylureas, and insulin, and it has additive effects with these drugs.

Diabetes is a progressive disease, said Drab, and eventually almost all patients will need insulin. He usually recommends a basal insulin to start. A basal insulin, such as insulin glargine (Lantus, Aventis), can control both fasting glucose and PPG, at least up to a certain point. When the disease progresses further and PPG again begins to rise, a short-acting (bolus) insulin may be necessary to control postprandial spikes in glucose. Because other insulins cannot be mixed with insulin glargine, the bolus insulins must be added as separate injections.

Another solution is to give a combination product, a mixture of a basal insulin and a bolus insulin. A recent study found that one such product, Novolog Mix 70/30 by Novo Nordisk (containing 70% insulin aspart protamine suspension and 30% insulin aspart injection), was more effective at controlling PPG than insulin glargine.

But there are some disadvantages to using combination products. For instance, in the study comparing Novolog Mix with insulin glargine, there were more cases of hypoglycemia with Novolog Mix. Another problem is the mixture ratio just doesn't work for some patients, said Drab. Patients may need an adjustment of one insulin and not the other, but that can't be done with a fixed-dose combination.