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Tight glycemic control not recommended for all patients with diabetes
Variability, lack of consistency across four major trials that examined effects of tight glycemic control.
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Researchers suggested that evidence does not strongly support tight glycemic control as more beneficial than harmful for reducing the risk for diabetes complications in patients with type 2 diabetes.
In fact, current evidence from major trials “requires a change in emphasis in our care for patients with type 2 diabetes,” according to Victor M. Montori, MD, MSc, and Mercè Fernández-Balsells, MD.
The researchers reviewed and summarized findings from the UKPDS, ACCORD, ADVANCE and VADT trials to determine if tight glycemic control was appropriate for patients with type 2 diabetes. The results of the major trials “suggest that tight glycemic control may not reduce the risk for all-cause or CV mortality, stroke, amputations or even microvascular complications,” they wrote in Annals of Internal Medicine.
Although data indicate a 16% reduction in risk for nonfatal myocardial infarction, intensive glycemic control demonstrated a twofold to threefold increased risk for severe hypoglycemia. The highest incidence of hypoglycemia was observed in trials with the lowest HbA1c targets, according to the researchers.
Considering recent data, health care professionals should avoid glycemic control interventions that overwhelm the patients’ ability to cope clinically, psychologically and financially, and instead focus on glycemic control efforts that individualized HbA1c targets, they recommended.
A “reasonable and feasible” HbA1c level is between 7% and 7.5% for many patients, according to the researchers.
Variability among trials
The researchers noted variability and lack of consistency of outcomes across the four trials.
For example, tight glycemic control increased mortality risk in the ACCORD trial and decreased risk in the UKPDS metformin trial.
Findings from subgroup analyses of the ACCORD and UKPDS metformin trials suggested that patients with earlier, milder disease might benefit from intensive glycemic control. These findings contradict similar outcomes in patients with newly diagnosed diabetes from the main UKPDS trial and in patients with long-standing diabetes from the ADVANCE trial.
Differences in medications used and focus of the outcomes in trials are a possible explanation for variation across trials, according to the researchers.
“Perhaps glycemic control is effective but not with the treatment strategies tested or we may have failed to fully understand the mechanisms by which diabetes causes complications and may have chosen incorrect therapeutic targets and goals,” they wrote.
The researchers cited an example from the ADVANCE trial in which the endpoint that demonstrated tight control was associated with the prevention of all diabetes-related complications by 10%, yet this effect was driven mostly by a decreased incidence of albuminuria.
“We believe clinicians should prioritize supporting well-being and healthy lifestyles, preventive care and CV risk reduction in these patients,” the researchers concluded.
However, additional research is needed, “particularly given the unequivocal patient burden, cost and harm of serious hypoglycemia associated with tight control,” they wrote.
Montori VM. Ann Intern Med. 2009;annals.org/cgi/content/full/0000605-200906020-00118v1.
Comments like these paint all patients with diabetes with the same brush. Very low HbA1c levels can be achieved in early type 2 diabetes when reasonable endogenous insulin secretion is available with agents that do not cause hypoglycemia (metformin, thiazolidinediones, dipeptidyl peptidase-4 inhibitors, incretin mimetics and alpha glucosidase inhibitors). However, later when and if the availability of endogenous insulin is limited and secretagogues or exogenou insulin is being utilized, hypoglycemia which probably increases cardiac risk, becomes the limiting factor and higher HbA1cs have to be accepted. Therefore, generalizations are inappropriate and may be harmful to individual patients with type 2 diabetes.
— David S. H. Bell, MD, FACE, FACP
Endocrine Today Editorial Board member