Impact of intensive lifestyle and metformin therapy on cardiovascular disease risk factors in the diabetes prevention program

Abstract

Objective: The Diabetes Prevention Program demonstrated the ability to delay or prevent type 2 diabetes in participants with impaired glucose tolerance (IGT). Participants with IGT are at high risk for cardiovascular disease (CVD), with a marked increase in the number and severity of CVD risk factors. We prospectively assessed the impact of our interventions on hypertension, dyslipidemia, and CVD events.

Research design and methods: The study group consisted of 3,234 individuals with IGT randomly assigned to receive intensive lifestyle intervention, metformin, or placebo. Annual assessment of blood pressure, lipids, electrocardiogram, and CVD events was undertaken.

Results: Hypertension was present in 30% of participants at study entry and then increased in the placebo and metformin groups, although it significantly decreased with intensive lifestyle intervention. Triglyceride levels fell in all treatment groups, but fell significantly more with intensive lifestyle intervention. Total cholesterol and LDL cholesterol levels were similar among treatment groups. Intensive lifestyle intervention significantly increased the HDL cholesterol level and reduced the cumulative incidence of the proatherogenic LDL phenotype B. At 3 years of follow-up, the use for pharmacologic therapy to achieve established goals in the intensive lifestyle group was 27-28% less for hypertension and 25% less for hyperlipidemia compared with placebo and metformin groups. Over an average of 3 years, 89 CVD events from 64 participants were positively adjudicated studywide, with no differences among treatment groups.

Conclusions: Lifestyle intervention improves CVD risk factor status compared with placebo and metformin therapy. Although no differences in CVD events were noted after 3 years, achieved risk factor modifications suggest that longer intervention may reduce CVD event rates.

Figures

Figure 1

Categorical changes in hypertension over time by treatment assignment. P represents the pairwise comparison from generalized estimating equation models.

Figure 2

Mean lipid levels by treatment assignment and year. A: Mean triglyceride levels. B: Mean HDL cholesterol levels. C: Percent with LDL phenotype B. P represents the pairwise comparisons of the treatment groups from repeated-measures models (A and B) and a general estimating equation model (C).

Figure 3

Prevalence of hyperlipidemia by treatment assignment. Hyperlipidemia was defined by either treatment with cholesterol or triglyceride-lowering pharmacologic therapy or by laboratory values meeting ATP II criteria for institution of drug terapy. P represents the pairwise comparison of treatment groups from generalized estimating equation models.