Patients who revert from impaired to normal glucose tolerance, especially those who do so via intensive lifestyle modification, can significantly reduce their cardiovascular risk factors, according to an analysis of data from the Diabetes Prevention Program.
The Diabetes Prevention Program (DPP) was a landmark study that showed that intervention with intensive lifestyle (ILS) modification and, to a lesser degree, metformin could reduce or delay the progression to diabetes over a mean 3.2 years follow-up in patients who had impaired glucose tolerance (IGT) at baseline (N. Engl. J. Med. 2002;346:393–403).
The new analysis in those 3,234 DPP patients also showed a lesser improvement with metformin (Diabetes Care 2009 Jan. 26; doi:10.2337/dc08–0494). “Importantly, improvement of glucose tolerance is associated with a more favorable risk factor profile, with intensive lifestyle accompanied by larger improvements than metformin,” said DPP writing group chair Dr. Ronald B. Goldberg, of the University of Miami, and his associates.
Overall, deterioration of glucose tolerance was associated with a worsening of risk factor levels, whereas improvement in status was associated with a beneficial risk factor change. The relationship between changes from normal glucose tolerance (NGT) to IGT to diabetes and changes in risk factors for cardiovascular disease (CVD) were significant for all risk factors except LDL peak particle density (LDL-PPD) in the intensive lifestyle group and for HDL cholesterol in the placebo group, they reported.
The biggest changes in CVD risk factor profile occurred among the patients in the intensive lifestyle group who transitioned from IGT to NGT. Their systolic blood pressure and triglyceride levels fell by about 25% over the study period, whereas HDL cholesterol and LDL-PPD increased by about 8% and 17%, respectively, from baseline.
Among those whose glucose tolerance status didn't change throughout the study, risk factors also didn't change among those with IGT. For those who achieved NGT during the study, risk factor profiles improved slightly in the intensive lifestyle group: Systolic blood pressure fell by 7%, diastolic blood pressure by 9%, and triglycerides by 7% from baseline, while HDL cholesterol and LDL-PPD increased by 5% and 6%, respectively.
Among the patients who progressed from IGT to diabetes, there were small—but mostly insignificant—deteriorations in their cardiovascular risk factor profiles. In the ILS group, progression from IGT to diabetes was not associated with any significant change in risk factors.
“There is no unique effect of conversion to diabetes but rather a linear relationship between glycemic measures and risk factor levels,” the researchers said.
'Improvement of glucose tolerance is associated with a more favorable [CV] risk factor profile.' DR. GOLDBERG