Primary Outcome Measures:
- percentage reduction in C-reactive protein (CRP) [ Time Frame: 14 weeks ] [ Designated as safety issue: No ]
Secondary Outcome Measures:
- insulin sensitivity and glycemic control [ Time Frame: 14 weeks ] [ Designated as safety issue: No ]
- change in lipids, specifically total cholesterol, LDL, HDL, triglycerides [ Time Frame: 14 weeks ] [ Designated as safety issue: No ]
- change in non-lipid biomarkers, specifically IL-6, TNF-alpha, RII, PAI-1 antigen, tPA antigen, adiponectin, leptin [ Time Frame: 14 weeks ] [ Designated as safety issue: No ]
- change in weight [ Time Frame: 14 weeks ] [ Designated as safety issue: No ]
- marked hypoglycemia [ Time Frame: 14 weeks ] [ Designated as safety issue: Yes ]
Study Rationale
Low-grade systemic inflammation as indicated by elevated levels of C-reactive protein (CRP) is often present in patients with type 2 diabetes. Individuals with type 2 diabetes represent a vulnerable population in which cardiovascular event rates are high and among whom CRP reduction may have the greatest impact. While several classes of oral hypoglycemic agents have been shown to lower CRP, data are not available for newer formulations of long-acting insulins such as Lantus (insulin glargine injection) and no study has comprehensively evaluated the relative merit of insulin-providing versus insulin-sensitizing strategies for this purpose.
Investigational Plan
This is a multicenter, community-based, randomized 2x2 factorial trial of Lantus and metformin among patients with type 2 diabetes treated with either diet or oral monotherapy (other than metformin) only who have poor glycemic control and elevated CRP. The primary endpoint is change in CRP. Secondary endpoints include improvement in insulin sensitivity, glycemic control, blood lipids, as well as selected inflammatory and prothrombotic markers, and adipokine levels.
Limited data suggest that short-term insulin administration in patients with poorly controlled type 2 diabetes may lower CRP, but the benefit of CRP reduction that is unique to insulin therapy and independent of glycemic control per se remains uncertain. The insulin-sensitizing agent metformin, a mainstay of anti-diabetic therapy, has been shown to reduce macrovascular complications among patients with type 2 diabetes and, in some but not all randomized clinical trials, also has a modest CRP-lowering effect. This study is designed to assess whether the use of Lantus either alone or in combination with metformin lowers CRP over a 14-week treatment period.
Eligible men and women age 18 to 79 years with early diabetes on diet only or oral monotherapy with baseline HbA1c 7.0-10% and CRP greater than or equal to 2.0 mg/l will be randomized in a 2X2 factorial fashion as follows. First, participants will be assigned at random to open-label Lantus or no insulin. Then, within these two categories, subjects will be assigned at random to metformin or placebo. Thus, the four resultant treatment groups are Lantus injection and placebo pill, Lantus injection and metformin pill, metformin pill alone, and placebo pill alone. All patients will receive diet and exercise counseling.
This study design will permit testing of the overall effect of Lantus as well as the effect of combination therapy with metformin for CRP reduction at a targeted level of glycemic control (fingerstick fasting blood glucose < 110 mg/dl). All participants will be provided with a glucometer for fingerstick glucose testing calibrated to report plasma-referenced values.
Purpose
