The role of Hemoglobin A1c in CVD

HbA1c was first discovered in 1955, however, in 1968 elevated levels were noted for the first time. Another 8 years passed before HbA1c was correlated with blood sugar values in hospitalized patients with diabetes and was proposed for monitoring glycemia.

There are two main kinds of diabetes: type 1 is caused by autoimmune destruction of insulin-producing ꞵ cells of Langerhans within the pancreas and sort 2 could be a result of both impaired insulin secretion and resistance to its action – often secondary to obesity.

During the primary few years of clinical use, HbA1c measures were inconsistent. The publication of the Diabetes Control and Complications Trial (DCCT) in 1993 made the importance of precise HbA1c measurement apparent.

This study found that the approximate 2% difference in HbA1c between standard- and intensive-insulin therapy groups resulted from a dramatically reduced risk of microvascular disease in patients with type 1 diabetes.

The continuation of the DCCT, the Epidemiology of Diabetes Interventions and Complications trial, and a study of patients with type 2 diabetes, the UK Prospective Diabetes Study (UKPDS), further supported the connection between sustaining a lower average HbA1c over time and improved patient outcomes, including CV events and mortality. Given the implications of small changes in HbA1c on morbidity, the requirement to cut back error margins in measurement became apparent.

The

National Glycohemoglobin Standardization Program (NGSP)

was founded in 1996 to control A1c measurements to DCCT standards. This program, now international in scope through involvement with the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), calibrates HbA1c measurements by outside laboratories and makers to reference standards.

Laboratories and makers that measure HbA1c certify through IFCC/NGSP and participate in yearly surveys to make sure inter-laboratory reproducibility. From 1993 to 2012 because of this successful program, standardization and accuracy of HbA1c measurements greatly improved.

Largely because of this fact, HbA1c was approved as a diagnostic tool by the American Diabetes Association (ADA) in 2009; the test has become a key measure for diagnosing, screening, and monitoring diabetes.

Advantages to HbA1c use in diagnosis include standardization of measurement, convenience as one blood-draw that doesn’t require fasting, minimal day-to-day variability, and preanalytic sample stability.

Although point-of-care testing for HbA1c is widely available, it’s not recommended for diagnostic use because these assays are generally not IFCC/ NGSP certified and don’t undergo identical proficiency testing as laboratory samples. Schematic for setting hemoglobin A1c (HbA1c) goals in keeping with a patient-tailored approach

Schematic for setting hemoglobin A1c (HbA1c) goals according to a patient-tailored approach

HbA1c & Cardiovascular Risk HbA1c has been established as a powerful predictor of CV events and mortality in patients with diabetes despite the absence of firm evidence that glycemic control modifies this risk substantially over time.

Results from the UKPDS and DCCT trials lend strong support to the hypothesis that glycemic control early within the course of disease provides preventive benefit. In contrast, three major trials that enrolled older patients at higher baseline risk showed no mortality or CV advantage of tighter glycemic control.

28–30 one amongst these, the Action to regulate Cardiovascular Risk in Diabetes trial, found increased mortality risk within the intensive glycemic-control arm among those that didn’t achieve the HbA1c target, illustrating the complexity of interpreting HbA1c in clinical practice.

While HbA1c may predict the chance of mortality and CV events in diabetes populations, it’s unlikely to be a powerful predictor in patients without established diabetes. Analysis of information from the Emerging Risk Factors Collaboration indicates that below the HbA1c diagnostic threshold of diabetes (< 6.5%), HbA1c is a smaller amount predictive than stronger risk factors like lipids.

31 during this retrospective analysis, including a cohort of over 200,000 individuals without diabetes, the danger model to predict CV events wasn’t enhanced significantly by the addition of HbA1c information.

The focus on HbA1c during the last 40 years has resulted in enhanced test accuracy, availability, and use among patients and providers within the care of diabetes. Because HbA1c has become the quality in how population-based studies evaluate the consequences of glycemic control on disease progression and complications, it is the premise for guidelines that address diabetes and CV risk definition and management.

Although HbA1c could seem familiar, there’s much not known about test interpretation and the way it’s going to actually miss the mark. As HbA1c use continues, these concerns must be clarified to optimize the screening, diagnosis, and care of patients with diabetes and CV disease.

Accurex has Xpress A1c an NGSP, IFCC & FDA approved providing results comparable to the HPLC method.

Accurex Biomedical

Accurex Biomedical Pvt. Ltd. is an Indian manufacturer and marketer which provides accurate and quality solutions in the diagnostic industry.

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