Setting A1c Goals for Patients with Diabetes Depends on a Variety of Factors

Do not overdiagnose diabetes, warned Guillermo E. Umpierrez, MD, FACP, a professor of Medicine at Emory University in Atlanta, during a presentation at the American College of Physicians Internal Medicine 2014 annual meeting held in Orlando, FL. He explained that an inappropriate diagnosis will follow the patient and may affect insurance and other options.

Since 2009, HbA1c is one of the tests physicians can use to diagnose diabetes. However, Umpierrez cautioned that other factors can alter HbA1c results. “Look at the fasting glucose,” advised Umpierrez.

He explained how the accepted method of diagnosis has changed over the years, from glucosuria in 1901 to the current guidelines, which include fasting glucose, two-hour postprandial glucose, or a random glucose test. The rationale for using HgA1c as diagnosis criteria involved studies that showed the incidence of retinopathy began to increase in patients with a HgA1c of 6.5%. It’s an easy test to perform, does not require fasting, and is unaffected by illness. Physicians can follow HgA1c over time and adjust therapy accordingly.

The limitations of using HgA1c include its cost, the lack of reliable testing in developing countries, and elevations in certain populations: patients with iron deficiency anemia, older adults, and blacks. HgA1c also cannot be trusted in patients with kidney disease or sickle cell anemia, he said.

Umpierrez declared fasting blood glucose as the best test to screen people. A normal result is less than 100 mg/dL. Subjects at risk are patients with a fasting blood sugar between 100-125 mg/dL or an HgA1c of 6.4%. If the test is greater than 100 mg/dL, he recommended ordering an HgA1c and possibly an oral glucose tolerance test, which is very specific but difficult on the patient.

“Repeat every test twice [before making a diagnosis],” he advised.

With at-risk patients, he advised to first try diet and exercise, with a 5 percent weight loss effective in preventing disease progression. If unsuccessful, metformin can be added, and will usually be more helpful in a younger person. Metformin should not be used to prevent diabetes in patients with a normal fasting blood sugar.

Umpierrez next addressed the pros and cons of intensive glycemic control and informed the internists in the audience that the trend has shifted from accepting glucose levels ranging from 200-300 mg/dL in the 1980s to tight control to the current move toward a middle ground. He discussed three studies showing that tighter control may not reduce heart disease, even though it does reduce microvascular complications. However, “all-cause mortality increased with tight control” in the ACCORD study of 2008.

“It was clearly unexpected, and it’s not clear why,” said Umpierrez, adding that hypoglycemia was associated with risk of death.

The American College of Physicians recommends keeping HgA1c levels around 7%. The American Diabetes Association guidelines range from less than 6% to more than 8%, depending on a variety of factors including attitude, risk of hypoglycemia, duration of time with the disease, age, co-morbidities, vascular complications, and resources.

“The goal is individualization of care,” Umpierrez said.

Umpierrez recommended aiming for an HgA1c of around 7%, no higher than 8%, except in patients with dementia who have a greater risk of hypoglycemia. If the patient takes only a medication not associated with hypoglycemia, such as metformin, the goal can be lower than 7%.