Efficacy and Safety of Colesevelam in Patients With Type 2 Diabetes Mellitus and Inadequate Glycemic Control Receiving Insulin-Based Therapy

BACKGROUND: Poor glycemic control is a risk factor for microvascular complications in patients with type 2 diabetes mellitus. Achieving glycemic control safely with insulin therapy can be challenging. METHODS: A prospective, 16-week, multicenter, randomized, double-blind, placebo-controlled, parallel-group study conducted at 50 sites in the United States and 1 site in Mexico between August 12, 2004, and December 28, 2005. Subjects had type 2 diabetes mellitus that was not adequately controlled (glycated hemoglobin level, 7.5%-9.5%, inclusive) receiving insulin therapy alone or in combination with oral antidiabetes agents. In total 287 subjects (52% men; mean age, 57 years; with a mean baseline glycated hemoglobin level of 8.3%) were randomized: 147 to receive colesevelam hydrochloride, 3.75 g/d, and 140 to receive placebo. RESULTS: Using the least squares method, the mean (SE) change in glycated hemoglobin level from baseline to week 16 was -0.41% (0.07%) for the colesevelam-treated group and 0.09% (0.07%) for the placebo group (treatment difference, -0.50% 0.09%; 95% confidence interval, -0.68% to -0.32%; P < .001). Consistent reductions in fasting plasma glucose and fructosamine levels, glycemic-control response rate, and lipid control measures were observed with colesevelam. As expected, the colesevelam-treated group had a 12.8% reduction in low-density lipoprotein cholesterol concentration relative to placebo (P < .001). Of recipients of colesevelam and placebo, respectively, 30 and 26 discontinued the study prematurely; 7 and 9 withdrew because of protocol-specified hyperglycemia, and 10 and 4 withdrew because of adverse events. Both treatments were generally well tolerated. CONCLUSIONS: Colesevelam treatment seems to be safe and effective for improving glycemic control and lipid management in patients with type 2 diabetes mellitus receiving insulin-based therapy, and it may provide a novel treatment for improving dual cardiovascular risk factors.