Weekly basal-bolus adjustments may reduce HbA1c levels in patients with type 2 diabetes

The efficacy of a simple algorithm and an insulin-to-carbohydrate ratio to both deliver and adjust prandial insulin may increase physician and patient willingness to advance to basal-bolus insulin.

In a 24-week, multicenter, randomized, controlled trial, researchers from the International Diabetes Center at Park Nicollet in Minneapolis and other U.S. sites compared a standard algorithm for adjusting glargine with two algorithms for adjusting glulisine. The intent-to-treat trial included 273 patients with type 2 diabetes.

The researchers randomly assigned 136 patients to a simple algorithm group, which received set glulisine doses to be taken before each meal, and randomly assigned the remaining patients to a carbohydrate counting group, which received an insulin-to-carbohydrate ratio to use for each meal. Patients in the latter group based their glulisine dose on the amount of carbohydrates consumed.

Based on levels of self-monitored blood glucose, glulisine and glargine were adjusted weekly in both groups.

At the end of the trial, HbA1c levels were 6.70% for the simple algorithm group and 6.54% for the carbohydrate counting group. From baseline to week 24, mean changes in HbA1c were -1.46% for the simple group and -1.59% for the carbohydrate group (P=.24). More than half of patients in each group achieved an HbA1c level <7.0% (simple: 73.2% and carbohydrate: 69.2%; P=.70).

The researchers reported a trend toward less weight gain and a lower daily dose of insulin in the carbohydrate counting group. – by Stacey L. Adams

Diabetes Care. 2008;31:1305-1310.

This is an interesting study. This is, conceptually, a comparison of a sliding scale versus insulin-to-carbohydrate counting. In the clinic, when I treat people, I am basically deciding if I give them a sliding scale of dose, or if I take a more sophisticated approach and go to carbohydrate counting. So, this simple algorithm is really at one level a sliding scale, but with some slight differences in terms of how to go about making adjustments. Either way, the HbA1c levels went down and the numbers were almost identical, which is rather interesting. The question that comes out of this study is, how feasible is it to do this in a practical, clinical setting? As a clinician, that is my first question. Also, as a clinician, if I wanted to use a mechanism to adjust insulin to carbohydrate ratios, this might be a much better way of doing so than just taking a shot in the dark.

– Aaron Cypess, MD, PhD

Associate and Staff Physician, Joslin Diabetes Center, Boston