A new study of older diabetes patients has found that well-controlled blood sugar levels were associated with a lower risk of major complications such as heart attacks, amputation and kidney disease, but the lowest blood sugar levels were associated with a small but significant increased risk of death. The study, published in the June issue of the journal Diabetes Care, followed more than 70,000 type 2 diabetes patients from Kaiser Permanente who were older than 60 years of age for 4years.
Because these findings come from an observational study and not a randomized clinical trial, more research needs to be done to fully understand their clinical implications, according to a press release.
“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,” Elbert Huang, MD, the study’s lead author and associate professor of medicine at the University of Chicago, stated. Researchers indicated that the best overall outcomes were found among those with intermediate levels of control
Huang and study co-author Andrew Karter, PhD, the study’s principal investigator at the Kaiser Permanente Division of Research in Oakland, Calif., jointly lead the Diabetes & Aging Study, the largest observational study to assess diabetes in older adults in the United States. The 5-year, NIH-funded study investigated care and health outcomes in older patients with type 2 diabetes in a typical community setting.
Most current guidelines suggest keeping glucose levels for patients with diabetes quite low. For people without diabetes, the normal glucose level — measured by a test called hemoglobin A1C, which reflects the average blood glucose level during the previous 3 months—is between 4% and 6%, compared to 6 and higher for patients with diabetes.
Because higher levels are associated with complications from this chronic disease, most recommendations for people with diabetes suggest maintaining an A1C 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,” Karter stated.
Finding the optimal A1C target is a balancing act, the authors note. The risk of all complications rose with blood sugar levels, but those with an A1C between 6% and 8% had the lowest death rates. While those with very poorly controlled blood sugars — A1C more than 10% — had the highest rates of death, those with an A1C below 6 were also at a somewhat higher than those with an A1C between 6% and 8%.
Since 1993, researchers involved in the Kaiser Permanente Northern California Diabetes Registry have collected extensive epidemiological data on diabetes care and observed health outcomes. The Diabetes & Aging Study follows patients managed by Kaiser physicians using internal care guidelines that mirror national clinical practice. Patients achieve varying levels of blood sugar control. Such community-based studies complement clinical trials by measuring whether the benefits of treatments measured in an experimental setting are also observed in usual practice settings.