Results of a 22-year study by researchers at Cardiff University School of Medicine in Wales indicate that older type 2s who try too hard to drive their A1c’s down to “normal” (4.5% to 6%) may significantly increase their chances of early death. In fact, the study, just published in the British medical journal The Lancet*, found that type 2s with the lowest risk of death had A1c’s of 7.5% — a figure that few authorities on the disease have recommended as ideal.
The study, which tracked almost 48,000 patients age 50 and older, also found that type 2s who used insulin to drive down blood sugar levels over the course of the study were 49 percent more likely to die than type 2s who used oral drug combinations, such as a sulfonylurea and metformin.
The study examined data that was collected from November 1986 to November 2008 for the UK General Practice Research Database. Overall, patients with the highest blood sugar levels over the course of the study ran a 79 percent greater risk of death, while patients with the lowest levels ran a 52 percent greater risk. The “safest” group was the patients with A1c’s of 7.5%.
The large-scale study confirms fears that were raised in the wake of the massive ACCORD study in the United States. That study, which tracked more than 10,000 type 2 patients, attempted to discern whether very tight control of blood sugar levels would lessen the risk of cardiovascular disease, a common result of diabetes’s inflammatory effects. Its sponsor, the U.S. government, abruptly terminated ACCORD in 2008 when a statistically significant number of diabetes patients with heart problems who had achieved tight control died from cardiovascular events.
The finding that using insulin as part of intensive treatment increased the risk of death led the researchers to two conclusions:
- Type 2 patients who need insulin may be more ill than other diabetes patients
- Doctors treating type 2s should try to handle their disease for as long as possible with a combination of diet, lifestyle, and oral medications before shifting to insulin therapy
As evidence increases that driving blood sugar levels too low may subject type 2s to as yet unexplained risks, older people with diabetes-and their doctors-may find themselves taking a “good enough” approach to A1c levels. The American Diabetic Association has long recommended an A1c of 7%, a figure that has come under fire at times for being too high. In the wake of the Cardiff University study, it would be ironic if people now start finding it “a bit low.”
*A synopsis of the study, “Survival as a function of HbA1c in people with type 2 diabetes: a retrospective cohort study,” is available at The Lancet.
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