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Simple Algorithm Method for
Insulin Dosing Safe, Effective

The traditional method of counting carbohydrates to determine
mealtime insulin dosing can be complicated and intimidating.

BY CONNI BERGMANN KOURY, EDITOR-IN-CHIEF

For many patients with type 2 diabetes, adjusting mealtime insulin glulisine (Apidra; Sanofi-Aventis, Paris) using a simple algorithm based on preprandial glucose is as safe and effective as using the traditional insulin-to-carbohydrate ratio.

According to a poster presented at the American Diabetes Association’s 66th Scientific Sessions in Washington, DC, the new algorithm may provide patients with an easier alternative to the more complicated carbohydrate counting method. Lead investigator Richard Bergenstal, MD, executive director of the International Diabetes Center in Minneapolis said the insulin-to-carbohydrate ratio is currently considered the gold standard, but it is a lot of work for the patient. “Some people get intimidated by [the counting carbohydrate method] and do not use it,” he said in an interview with Diabetic Microvascular Complications Today.

The open-label, multicenter, randomized trial evaluated starting patients on a fixed-dose of mealtime glulisine and using an algorithm to adjust the glulisine to target based on preprandial glucose patterns, compared with starting and adjusting glulisine to target using the insulin-to-carbohydrate ratio. In the 24-week study, 136 patients were assigned to the simple algorithm group and 137 were assigned to the insulin-to-carbohydrate group.

UNCONTROLLED DIABETES
All study patients had uncontrolled type 2 diabetes with two or more insulin injections. The mean age of the patients was 55.1 years, mean body mass index was 36.7 kg/m2 and the mean baseline HbA1c was 8.2%.

Patients were switched to basal:bolus therapy with daily glargine (Lantus; Sanofi-Aventis) titrated to achieve fasting plasma glucose <95 mg/dL and glulisine before meals with targets of <100 mg/dL before lunch and dinner and <130 mg/dL at bedtime (with or without metformin).

Dr. Bergenstal said premeal glulisine was adjusted weekly. The algorithm group added 1, 2 or 3 U/kg based on premeal patterns and the carbohydrate count group adjusted the insulin-to-carbohydrate ratio.

PATIENTS REACHED GOAL
After 24 weeks, patients using both methods of dosing were able to achieve mean HbA1c levels of 6.6% (Figure 1). There was no difference between the algorithm and the insulin-to-carbohydrate groups with regard to HbA1c decrease (-1.46% vs -1.59%, P=.24), the proportion of patients achieving HbA1c <7% (73.0% vs 69.2%, P=.7) and weight gain (3.7 kg vs 2.4 kg, P=.06).

Patients in the algorithm group had higher doses of glulisine (110.2 U vs 94.3 U, P=.04) and glargine (103.4 U vs 87 U, P<.0001) and less symptomatic hypoglycemia <50 mg/dL (4.9 vs 8.0 events/patients yr, P=.02) compared with the insulin-to-carbohydrate group.

Both groups ended with a basal:bolus ratio of 50:50 and used 1.8 to 2 U/kg of insulin per day.

“We found that physicians really need to keep an open mind and do what is best for the patient,” Dr. Bergenstal said. “If patients want to do the insulin-to-carbohydrate ratio, that’s fine, but if they want something simple with pattern control, that can work, too. The key thing is to have a target goal, do the blood sugars and adjust by either method.”

The researchers concluded that this simple approach may help patients learn to initiate and adjust bolus insulin, thereby improving the transition to basal-bolus regimens and their effectiveness. This may also encourage physicians to initiative insulin earlier in patients with type 2 diabetes who fail oral agents.

“This new dosing approach relies on a simple algorithm that allows patients to start with a fixed dose of mealtime glulisine and then adjust to target based on premeal glucose patterns,” Dr. Bergenstal emphasized. “This is an easy way to dose and adjust mealtime insulin that should meet the needs of many patients who are not prepared to undertake the equally effective but more complex carbohydrate counting method. Also, the HbA1c reductions seen in this study help further demonstrate that good glycemic control is possible and often associated with basal:bolus regimens.”

Richard M. Bergenstal, MD, has been an endocrinologist in practice for over 20 years and is the executive director of the International Diabetes Center and senior vice president of Park Nicollet Institute, Park Nicollet Health Services in Minneapolis. He is clinical professor in the department of medicine at the University of Minnesota and chief medical editor of Diabetic Microvascular Complications Today. He may be reached at bergerm@parknicollet.com.

Bergenstal R, Johnson M, Powers M, Wynne A, et al. Using a simple algorithm to adjust mealtime glulisine based on preprandial glucose patterns is a safe and effective alternative to carbohydrate counting. Presented at the American Diabetes Association’s 66th Scientific Sessions. June 9-13, 2006. Washington, DC.
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