New research finds that older diabetics with better control of their blood sugar face less chance of such diabetes-related complications as heart attacks, amputation and kidney disease.
However, there's a twist: those with the lowest blood sugar levels face a slightly higher chance of dying than do those whose blood sugar control is in a more normal range.
Researchers tracked more than 70,000 people with type 2 diabetes for four years. All were older than 60. "We saw increased mortality and complications, as anticipated, among those with very high blood sugars, but we also saw a modestly increased risk of death among those with very low levels of blood sugar," Dr Elbert Huang, an associate professor of medicine at the University of Chicago and the study's co-lead author, said.
People did the best if they had intermediate control of their blood sugar, the study found.
Controlling blood sugar levels
Guidelines typically recommend that those with diabetes keep their glucose levels low with a haemoglobin A1C level of less than 7%. "We need more evidence regarding how well the 7% guideline, which was based on a 1998 British trial that excluded older patients, applies to patients over the age of 60," Andrew J. Karter of the Kaiser Permanente Division of Research, who led the study along with Huang, said.
A 2008 study found that older people with diabetes were more likely to die if they took treatments geared toward intensively lowering their glucose levels.
"In our study, we found the best overall outcomes among those with the intermediate levels of control, those with A1Cs below 8% but above 6%," Huang said. "We observed similar patterns for those in their 60s, 70s and over 80."
Why might lower levels be linked to risk for death? "We cannot say whether this unexpected finding is due to the very low blood sugar itself, the treatments used to control blood sugars or to some other factors not directly related to the care of diabetes," Karter said. "It may be that the sickest patients at high risk of dying simply had low blood sugars to start with, rather than anything directly associated with the care of diabetes increasing the risk of death."
The study is published in the journal Diabetes Care.
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