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Risks Associated With Low A1C Target

En Español (Spanish Version)

Poorly controlled diabetes can lead to significantly increased risk of heart disease (CVD), peripheral neuropathy , amputations , retinopathy, and kidney disease. The A1c blood test is considered a good indicator of overall blood glucose control. The current recommendation to decrease complications of diabetes is an A1c level less than 7%. Some medical professionals have looked into the benefit of aiming for A1c’s even lower, below 6%, commonly called intensive blood glucose control. There is conflicting information as to whether the lower rate is beneficial.

Two studies published in the New England Journal of Medicine looked at the benefits and risk of intensive blood glucose control therapy. The results of both studies suggest it may be more harmful than beneficial to target the A1c less than 6.5%.

A group called the Action to Control Cardiovascular Risk in Diabetes (ACCORD), investigated intensive therapies ability to decrease CVD risk. The study was stopped early because of higher rates of death in the intensive treatment group. The second study was conducted by the Action in Diabetes and Vascular Disease group (ADVANCE). Their study followed intensive therapy with drug interventions and found an increase in hospitalization and low blood sugar with intensive blood sugar lowering.

About the Studies

The ACCORD trial was a randomized control study that followed 10,251 patients with type 2 diabetes. Patients were assigned to a standard therapy group or an intensive therapy group. The patients were tracked for any significant cardiovascular event including death.

The study was halted at 3.5 years when the intensive therapy group was found to have a higher mortality rate. Also, at 3.5 years there were no significant reductions in cardiovascular events for the intensive therapy group.

The ADVANCE study followed 11,140 patients with type 2 diabetes. Participants were assigned to standard glucose control or intensive glucose control. The intensive glucose control used gliclazide and other drugs to reach an A1c level of 6.5% or less. While there was no difference is mortality between the groups, there was a significantly increased rate of hospitalization and hypoglycemia (dangerously low blood sugar), in the intensive glucose control group. The intensive glucose control group did benefit from slower progression of diabetic kidney disease but the long-term benefits of this are not known.

How Does This Affect You?

Lowering blood sugar is an important part of controlling diabetes along with exercise and diet. Work with your doctor to decide what level is safe and beneficial for you. Do not try to lower your blood sugar or change your medications without consulting your doctor. Low blood sugar can be very dangerous.




  • Gerstein HC, Miller ME, Byington RP, et al. Effects of intensive glucose lowering in type 2 diabetes. N Engl J Med . 2008 Jun 12;358(24):2545-59.
  • Patel A, MacMahon S, Chalmers J, et al. Intensive blood glucose control and vascular outcomes in patients with type 2 diabetes. N Engl J Med . 2008 Jun 12;358(24):2560-72.

Last reviewed July 2008 by Larissa J. Lucas, MD

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