Long-term effects of the Diabetes Prevention Program interventions on cardiovascular risk factors: a report from the DPP Outcomes Study

Abstract

Aims: Whether long-term cardiovascular risk is reduced by the Diabetes Prevention Program interventions is unknown. The aim of this study was to determine the long-term differences in cardiovascular disease risk factors and the use of lipid and blood pressure medications by the original Diabetes Prevention Program intervention group.

Methods: This long-term follow-up (median 10 years, interquartile range 9.0-10.5) of the three-arm Diabetes Prevention Program randomized controlled clinical trial (metformin, intensive lifestyle and placebo), performed on 2766 (88%) of the Diabetes Prevention Program participants (who originally had impaired glucose tolerance), comprised a mean of 3.2 years of randomized treatment, approximately 1-year transition (during which all participants were offered intensive lifestyle intervention) and 5 years follow-up (Diabetes Prevention Program Outcomes Study). During the study, participants were followed in their original groups with their clinical care being provided by practitioners outside the research setting. The study determined lipoprotein profiles and blood pressure and medication use annually.

Results: After 10 years' follow-up from Diabetes Prevention Program baseline, major reductions were seen for systolic (-2 to -3) and diastolic (-6 to -6.5 mmHg) blood pressure, and for LDL cholesterol (-0.51 to -0.6 mmol/l) and triglycerides (-0.23 to -0.25 mmol/l) in all groups, with no between-group differences. HDL cholesterol also rose significantly (0.14 to 0.15 mmol/l) in all groups. Lipid (P = 0.01) and blood pressure (P = 0.09) medication use, however, were lower for the lifestyle group during the Diabetes Prevention Program Outcomes Study.

Conclusion: Overall, intensive lifestyle intervention achieved, with less medication, a comparable long-term effect on cardiovascular disease risk factors, to that seen in the metformin and placebo groups.

Trial registration: ClinicalTrials.gov NCT00038727.

Figure 1

Changes in cardiovascular disease risk factors from baseline by treatment group. Mean changes from baseline are adjusted for baseline level. For triglyceride changes, the means are calculated in the log scale and changes are calculated as (per cent change − 1) × mean at baseline. Data presented are based on number of participants with annual visits, which include: year 1 = 2711, year 2 = 2717, year 3 = 2698, year 4 = 2635, year 5 = 2584, year 6 = 2552, year 7 = 2519, year 8 = 2518, year 9 = 2473, year 10 = 1636.

Figure 2

Per cent change in (a) HDL cholesterol, (b) LDL cholesterol and (c) triglycerides by treatment group and statin use at visit. Per cent changes in mean (95% CI) are adjusted for baseline levels. The numbers represent participants included for the year and statin status. Statin status is based on reported concomitant medications at current year.

Figure 3

Proportion of each treatment group meeting guideline criteria by diabetes status at each visit. Data presented are percentage meeting guideline with 95% CI. The numbers represent participants included for the year and diabetes status. Diabetes status is current status for the year. Hypertension was defined as use of anti-hypertensive medications or systolic/diastolic blood pressure ≥ 140/90 for participants without diabetes or systolic/diastolic blood pressure ≥ 130/80 with diabetes. Dyslipidaemia is meeting any of the three criteria: triglyceride ≥ 1.7 mmol/l, LDL cholesterol ≥ 2.6 mmol/l or use of lipid-lowering medications.