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VADT: Intensive glucose control did not impact CVD risk
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Aggressive blood glucose control had no significant effect on cardiovascular disease reduction in patients with type 2 diabetes, according to recent findings from the Veterans Affairs Diabetes Trial.
The 7.5-year large-scale intervention trial studied the effects of intensive glucose control on CVD risk in 1,791 U.S. veterans (97% men; 62% non-Hispanic white; mean age, 60). Patients were assigned to two groups — intensive glucose control (HbA1c goal <7%) and standard glucose control.
While intensive glucose control suggested some benefits, it did not reach statistical significance for the primary endpoint, a composite of specific CVD events (P=.12), according to William C. Duckworth, MD, director, Diabetes Research, Carl T. Hayden VA Medical Center, Phoenix.
At baseline, “our glycemic control (mean, 9.5%) was the worst of all the three trials that have been presented here,” said Carlos Abraira, MD, professor of medicine, Miami VA Medical Center, referring to the ACCORD and ADVANCE trials. Forty percent of patients had prior cardiovascular events, 80% had hypertension, 50% had lipid abnormalities and the majority were obese.
“We found we could very tightly control blood glucose and risk factors (HDL, LDL, triglycerides) within two years in both arms,” Abraira said. The greatest improvement was change in blood pressure — from 131/77 mmHg at baseline to 127/70 mmHg within six months. HbA1c was reduced to 8.4% among standard control patients and 6.9% among intensive control patients also within six months.
Duckworth said the most important finding was that severe hypoglycemia (impairment/loss of consciousness within the previous three months) was a powerful predictor of cardiovascular events (HR=2.062; P=.018). It was reported in 21% of patients receiving intensive control and 10% receiving standard control.
Data in the VA Diabetes Trial regarding rosiglitazone (Avandia, GlaxoSmithKline) was noteworthy as well. Thomas E. Moritz, MS, presented data suggesting rosiglitazone was not associated with excess cardiovascular events.
“If anything, rosiglitazone showed a protective effect rather than a harmful effect,” said Moritz, a statistician at Hines VA Hospital, Ill.
Patients received two to three oral antidiabetes agents, including rosiglitazone, metformin and glimepiride, plus insulin. Rosiglitazone was the most commonly used — by more than 80% of patients in both groups. There were no reports of increased deaths and fewer cardiovascular events than expected, according to a case-control analysis and time-dependent analysis.
“We predicted ahead of time how many incidences we would have (650 to 700 events). We did not come anywhere near the number we predicted (standard group, 263; intensive group, 231),” Duckworth said.
The rosiglitazone analyses were conducted because “we felt obligated at the time to look at this as a safety issue in our patients,” though it was not included in the original study outline, Moritz said. – by Katie Kalvaitis
For more information:
- Abraira C, Moritz TE, Reaven P, et al. Glycemic control and cardiovascular outcomes – the VA Diabetes Trial. Presented at: ADA 68th Scientific Sessions; June 6-10, 2008; San Francisco.
Lack of effect of glucose control in the VADT, as with other major interventional trials, suggests that other proven predictors of cardiovascular risk be reemphasized in terms of patient management. A focus on lipid management, especially LDL and blood pressure management, seems highly appropriate in light of these findings. Nevertheless, glucose control should not be abandoned otherwise risk of microvascular complications will increase dramatically.
– Alan J. Garber, MD, PhD
Cardiology Today Editorial Board member
It is very important to the ADA that these three big trials — VADT, ADVANCE, ACCORD — be reported at the same time because without having the answer to these three trials at the same time it would be hard to move forward in the field with regards to how diabetes should be treated in the future.
– John Buse, MD
President-Elect, Medicine and Science, ADA