Swedish researchers report that a drop in A1C of less than one percentage point can lower the risk of death from cardiovascular disease among people with diabetes by nearly half. Specifically, they found that patients who reduced their A1C from 7.8% to 7.0% decreased their risk of dying from cardiovascular disease by 45 percent.
That percentage was based on statistics showing that the absolute risk of death from cardiovascular causes is 9.9 events per 1,000 person-years in patients with the lower A1C, versus 17.8 events per 1,000 person-years in patients with a higher baseline or increasing A1C. In addition to the decreased risk of death from cardiovascular events, the Swedish researchers noted that better glycemic control reduced the risk of nonfatal cardiovascular events.
The University of Gothenburg study analyzed data on 18,000 patients from the Swedish National Diabetes register. The patients had a baseline A1C of between 7% and 8.9%, spanned the ages of 30 to 75 years, and had a median duration of diabetes of eight to 10 years. The researchers designed the study to exclude patients with a history of cardiovascular problems. They divided the patient histories they studied into one group that had shown a decreasing A1C after starting at a baseline of 7.8%, and a second group whose A1C had remained stable at a baseline of 7.7% or had increased.
Lead researcher Katarina Eeg-Olofsson, MD, said that her team began the study to look into the connection between tighter glycemic control and cardiovascular problems. The noted US ACCORD study (Action to Control Cardiovascular Risk in Diabetes), which investigated the effects of tight glycemic control, was suspended in 2010 after scientists concluded there might be a link between tight control and increased cardiovascular problems. At the same time, a large European study designed to investigate the same relationship did not show such a link.
Based on her study’s results, Eeg-Olofsson said that a 7% A1C seems to be a target that type 2s can aim for to help mitigate the increased risk of cardiovascular problems that affect people with diabetes.
The team reported its findings at the recent 72nd Scientific Sessions of the American Diabetes Association. An abstract is available here.