Chevy Chase, MD—A study published this week in Lancet suggests that low A1C levels may be just as dangerous as high A1C levels in diabetes patients with respect to mortality and cardiovascular outcomes. Upon review of the study, The Endocrine Society released today a statement recommending against any wholesale change in glycemic goals and strongly encourages patients to discuss these issues with their diabetes-care providers.
Measurements of A1C show the percentage of hemoglobin (the main component of red blood cells) in the blood that is glycated, i.e., has glucose attached to it. The A1C blood test is currently one of the mainstays of diabetes management because it reflects the average blood sugar levels for the previous two to three months.
The study by Currie et al. published online in the January 27, 2010 issue of Lancet is a retrospective database analysis using information on almost 50,000 patients contained in the United Kingdom’s General Practice Research Database. Researchers found that patients with both the lowest A1C levels (median 6.4 percent) and the highest A1C levels (median 10.5 percent) were at significantly higher risk of death or cardiovascular events when compared to patients at lowest risk (median A1C level of 7.5 percent). Despite these findings, The Endocrine Society does not recommend changes in glycemic control goals be implemented at this time.
“While the results of this study are provocative, they don’t definitively show a cause and effect relationship between low A1C levels and mortality,” said Robert A. Vigersky, MD, president of The Endocrine Society. “There are too many unknown factors that may have contributed to these results to say definitively that aggressive glycemic control raises cardiovascular risk and mortality. Unknown factors include the method of patient selection, reporting requirements, and the potential impact of pre-existing conditions for patients included in the database. For example, 63 percent of the patients evaluated in the study were smokers and others already had evidence of either macrovascular or microvascular disease.”
Because Currie et al.’s mortality results are consistent with those of the ACCORD study–a large clinical study of adults with diabetes which was terminated early because of increased mortality rate in those intensively controlled–diabetes-care, the Society suggests that providers may want to reassess the glycemic goals for their patients on an individual basis using known risk factors. The statement reminds providers that virtually all studies have shown that intensive glycemic control reduces microvascular complications, i.e., damage to the eyes, kidneys, and nerves.
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Founded in 1916, The Endocrine Society is the world’s oldest, largest, and most active organization devoted to research on hormones and the clinical practice of endocrinology. Today, The Endocrine Society’s membership consists of over 14,000 scientists, physicians, educators, nurses and students in more than 80 countries. Together, these members represent all basic, applied, and clinical interests in endocrinology. The Endocrine Society is based in Chevy Chase, Md. To learn more about the Society, and the field of endocrinology, visit our web site at www.endo-society.org.