Tag Archives: Glycated hemoglobin

10-year Study Proves High Blood Sugar Linked With Retinopathy Risk

Here is more evidence that uncontrolled blood sugar (hyperglycemia) increases the risk of diabetic retinopathy (blindness). Individuals who have poorly controlled type 1 or type 2 diabetes may be at greater risk of developing retinopathy, according to a new study from a team of French researchers. They found that persistently high levels of blood sugar are a strong indicator of future retinopathy risk.

In a cohort study, the risk of the condition shot up markedly when fasting plasma glucose and glycated hemoglobin (HbA1c) reached levels that are used to indicate diabetes risk, according to Beverley Balkau, PhD, of the Institut National de la Santé et de la Recherche Médicale in Villejuif, France, and colleagues.

The finding allows physicians to set threshold values that define patients at risk of the eye condition, they argued in the February issue of Archives of Ophthalmology. They said the information helps clear up some debate over the role that blood sugar levels play in the development of retinopathy and could provide medical professionals with a way of measuring a patient’s risk for the condition.

For the study, Balkau and colleagues studied more than 700 men and women taking part in the DESIR study, which enrolled volunteers ages 30 to 65 in western France from 1994 to 1996. At the outset, doctors examined participants’ retinas and took blood sugar readings. The individuals were then followed for a period of ten years.

The goal was to study the frequency of retinopathy in individuals 10 years after measuring baseline levels of fasting plasma glucose and HbA1c and to evaluate positive predictive values for retinopathy at various levels of the glycemic variables.

After a baseline health exam, all participants were asked to return for subsequent examinations three, six, and nine years later. Those who were diagnosed with diabetes or who had had a fasting glucose level of at least 126 mg/dL at any point during the study were asked to undergo testing for retinopathy using a nonmydriatic digital retinal camera.

For comparison, two groups of matched participants also had the retinal exam ‒ those who had had an impaired fasting glucose level (from 110 through 125 mg/dL) at any time during the study and those whose glucose levels had always been below 110 mg/dL.

By the end of the study period, the researchers noted a strong correlation between initial blood sugar readings and the development of retinopathy. Participants with the condition had 22 percent higher fasting blood sugar levels and 12 percent higher HbA1c levels at the start of the study compared to participants who did not develop retinopathy.

All told, the researchers found 44 participants with retinopathy, including 19 of 237 in the diabetes group, another 19 of 246 with impaired glucose levels, and six of 249 in the normal glucose group.

Those with retinopathy had higher baseline fasting glucose and HbA1c levels on average — 106 versus 130 mg/dL and 6.0% versus 6.4%, respectively (P<0.001).

And a higher percentage were treated for hypertension ‒ 36.4% of those with retinopathy compared with 19.6% (P=0.008), and they had a trend toward higher systolic blood pressure.

Analysis also showed that:

• Fasting plasma glucose levels of 108 and 116 mg/dL had positive predictive values of 8.4% and 14.0%, respectively, for retinopathy.

• HbA1c levels of 6.0% and 6.5% had positive predictive values of 6.0% and 14.8%, respectively.

Because of the sharp increase, they argued, the lower levels of each marker should be used as thresholds to identify those at risk of retinopathy 10 years down the road. “We propose that thresholds of 108 milligrams per deciliter for fasting plasma glucose concentration and 6.0 percent for HbA1c level could be used to define those who are at risk of retinopathy,” they wrote.

Balkau and colleagues noted that the study’s strengths included a large sample size and long follow-up.

However, they cautioned that the study participants were self-selected individuals who volunteered for the study after a free health checkup and the sample size of those with retinopathy was small, allowing evaluation only of risk factors strongly associated.


WHO Formally Accepts HbA1c Test for Diabetes Diagnosis

The World Health Organisation (WHO) has formally accepted the use of the HbA1c test for the diagnosis of diabetes, rather than the more common method of taking a blood sample and checking it for glucose content.WHO have assessed the HbA1c test as a way of measuring how much glucose is being carried by the red blood cells in the body and shows a person’s levels of blood glucose for the previous two or three months.

The HbA1c test is an easier test for diagnosing, as the use of blood samples meant people sometimes had to fast and then consume a high glucose drink, with blood being taken before and after and the levels of glucose compared.

WHO have stated that the HbA1c test, although more costly, does provide a more practical and easier technique for diagnosing the metabolic condition, but warned that rigorous quality assurance tests must be put in place and measurements standardised.

Ala Alwan, assistant director general of the Non-communicable Diseases and Mental Health Cluster at WHO, commented “Unlike other means of diagnosis, it does not require a patient to fast before a blood sample is taken, nor to consume a glucose drink that many people find unpalatable. HbA1c also has the advantage of reflecting the person’s average blood glucose levels over the preceding two–three months.”

Simon O’Neill, director of care, information and advocacy, at charity Diabetes UK, also said “This recommendation does not mean other tests for diagnosing diabetes will be shelved. Doctors will continue to use their clinical judgement about which test is most appropriate for their patients on an individual basis.”

The A1C: A Better Way to Diagnose Pre-Diabetes

According to research by Ronald Ackermann, MD, MPH, of the Indiana University School of Medicine, the A1C test, which is commonly used to track blood sugar levels of those with diagnosed diabetes, might be just the ticket to diagnose the growing masses with pre-diabetes.

The current test for pre-diabetes, the fasting plasma glucose (FPG) test, is a pain in the neck, requiring two visits to the doctor, the second one after an inconvenient overnight fast. But the A1C test, which measures a patient’s average blood glucose level over the preceding two to three months, is a relative snap, requiring only one visit and no fasting.

Currently, a diagnosis of pre-diabetes requires an FPG concentration between 110 and 125 mg/dL. Among adults meeting that criterion, about a third develop type 2 diabetes within eight years. According to Dr. Ackermann’s study of 1750 people, an A1C between 5.5% and 6.5% (the cut-off for full-blown diabetes) identifies adults with that same risk of developing type 2. An A1C of 5.7% or more identifies people with a risk for diabetes of 41.3 percent.

Five years ago, Dr. Ackermann reported that it would be cheaper to pay for diabetes prevention when patients are only 50 years old than it would to wait until they’re 65 and probably in need of more expensive treatments.  Recently, some health plans have agreed with that logic and begun paying for diabetes prevention programs.

The catch is that in order to qualify for the programs, patients must have been formally diagnosed with pre-diabetes. Making the A1C a standard screening test for those with risk factors could make a huge difference in the lives of millions, preventing not only type 2 diabetes, but also cardiovascular disease.

Sources: EurekAlert, American Journal of Preventive Medicine

How Long Does it Take to Lower Your A1C Levels?

Red blood cells and the hemoglobin they contain have an average life span of 120 days during which glucose molecules are exposed to the red blood cells and form glycated hemoglobin. Therefore, in theory, changes in your A1C levels won’t be apparent for at least the 120 days it takes for the affected red blood cells to complete a life cycle.

The amount of time it takes to lower your A1C depends on how big of a change you are trying to achieve. If your A1C is in the double digits, it may take a matter of 2 or 3 months to see a significant change if your diabetes management is consistent and tight. If your A1C is a point or two away from ADA/AACE recommendations, getting to goal may take a little longer.

“Lowering your HbA1c from a [high] number to an 8.0 or 7.5 is much easier than lowering it from a 7.5 to 6.5,” said dLife Expert CDE Claire Blum in response to a question about lowering A1C levels. “Tightening of control that occurs at the lower numbers takes a lot of fine tuning. Our bodies also require some time to adapt to the change of improved [levels].”

There are no special tricks to getting your A1C to a level more acceptable to you and your doctor. Lowering your A1C is doing just what your doctor has always told you was best for good diabetes management.

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