HbA1c – an important marker
HbA1c (A1c or glycosylated hemoglobin) is widely used as the most important marker for routine monitoring of long term glycemic status in patients with diabetes. It is used as a measure of future risk for the development of diabetes complications. HbA1c can be used to diagnose diabetes mellitus but the most common and widely used methods are:
- Fasting Plasma Glucose (FGP)
- Oral Glucose Tolerance Test (OGTT)
When used for diagnosis and screening for diabetes, the HbA1c test method should be certified by the NGSP, standardized to the Diabetes Control and Complications Trial (DCCT) assay, and traceable to the IFCC reference method.
Why measure HbA1c?
Monitoring of HbA1c in diabetics is recommended by international guidelines for patients with diabetes mellitus and is the golden standard since 1970s.
ADA, IDF and WHO recommends that HbA1c should be measured routinely in all patients with diabetes mellitus to document their degree of glycemic control:
- Two to four times per patient and year
- As index of mean glycaemia and
- As a measure of risk for the development of diabetes complications
Benefits of HbA1c Control
The UKPDS found that better control of HbA1c leads to better outcomes in patients with diabetes. As little as a reduction in 1 percentage unit from 8% to 7% of HbA1c resulted in 21% decrease in deaths related to diabetes, 37% decrease in microvascular complications and 14% decrease in myocardial infarction.
Measurement of urine albumin should be used for the purpose of screening for, monitoring and to supplement the clinical evidence in the diagnosis and treatment of microalbuminuria. Microalbuminuria, a condition in which low but abnormal amounts of albumin are present in the urine, is increasingly recognized as an early-risk marker for chronic kidney disease as well as for cardiovascular disease. Numerous studies have linked an elevated urine albumin level in people with diabetes to a dramatically increased risk for diabetic nephropathy.
Screening for microalbuminuria is a matter of urgeny
Early detection and treatment slow down or even prevent the onset of chronic kidney and cardiovascular disease. Microalbuminuria predicts renal complications in diabetes patients as well as hypertensive patients and in the general population without diabetes or hypertension.
Considering that this inexpensive procedure is seldom performed in clinical practice, even among people at risk, the International Society of Nephrology has urged focus on 3 risk groups: people with diabetes, people with hypertension, people older than 50 years with a family history of diabetes and/ or cardiovascular disease.
Definitions, cutoffs and screening
Microalbuminuria is defined as 20-200 mg/L in a first-morning spot sample or 30-300 mg/L in a random spot specimen. Cutoffs for albumin are the same for men and women of any age and ethnicity, and albumin concentration is not effected by muscle mass. Albumin concentration offers the same sensitivity at a fraction of the cost as albumin/creatinine ratio as long as the patient has not consumed abnormal amounts of liquid.
Studies have shown that by screening for microalbuminuria and monitoring its progress, treatment of patients with diabetes can be further optimized. ADA and other guidelines recommend annual screening for patients with type 1 diabetes from 12 years of age, or 5 years after diagnosis of type 1 diabetes. For type 2 diabetes patients annual screening is recommended at the time of diagnosis and until the patient is 70 year old as microalbuminuria can already be present at the time of diagnosis.