What Is An AGP?
Ambulatory Glucose Profile (AGP) is a single page, standardized report for interpreting a patient's daily glucose patterns. This can be obtained about 5 days after the application of the CGM sensor. AGP, utilized by a healthcare practitioner, provides both graphic and quantitative characterizations of daily glucose patterns for 5- 14 days that offer insights on glucose behavior in every diabetes patient. These insights can then be checked by your doctor per the patient’s daily habits like food intake, medicines, activities. Changes could be suggested to modify daily habits that will be suitable to every patient, offering a better control on glucose fluctuations, thereby, controlling HbA1c and other glucose parameters or levels.
AGP and TIR
Time in range (TIR) is widely gaining popularity as a crucial parameter of glucose control. Essentially it just indicates how long in an average day, has the patient’s blood sugars been within the doctor specified target range, usually 70-180 mg/dl. Different diabetic subset of patients have different TIR standards as per international recommendations. TIR is measured as %, and as an example, a young type 2 Diabetic patient should have a TIR of >70% with <1% hypoglycaemia. There is emerging evidence that patients with good TIR have lesser long term complications of diabetes.
An accurate analysis of TIR can only be made when a large number of glucose readings are available at all times of the day for a period of at least 14 days. Only a 14 day AGP which checks sugars continually for 14 days can precisely meet this criteria.
AGP and Glucose variability
Glucose variability is defined as frequent and rapid rise and fall in glucose levels that fluctuate over a period. Such fluctuations cause release of reactive oxygen species that may lead into various diabetic complications like retinopathy, nephropathy, stroke etc. The standard tests currently used (FBS/PLBS/Hba1c) do not reveal any insights about the Glycaemic variability.
AGP provides a comprehensive assessment of the glycaemic variability, as it clearly demarcates how various daily glucose readings at a certain time of the day vary across different days during the period of the AGP. After assessing the glucose variability on the AGP, the doctor can tailor the treatment or other lifestyle changes to significantly reduce the risk of diabetic complications.
AGP and Hypoglycemia
One of the most useful features of AGP is to reveal the nighttime hypoglycemia in patients who otherwise do not complain of any symptoms of low sugar. Hypoglycemia unawareness is a serious undiagnosed condition which can lead to coma. This pattern warns the doctor who can take necessary treatment plans to avoid further hypoglycemia.
AGP and Hba1c
The standard Hba1c measured in the lab, although is an important tool in diagnosis and monitoring of Diabetes, has a few limitations.
- Hba1c does not take into account the hypoglycaemia experienced by the patient. It is only a measure of how normal or high the patient’s sugars have been over time
- Hba1c has a lot of inter lab variability, due to lack of standardisation of across different labs in India
- Hba1c tends to be falsely high or low, if the patient has an abnormal haemoglobin trait. This trait if present is silent in nature and the patient may not be aware of it
AGP report gives an estimated A1c, which is calculated from the measured glucose readings. Hence, it reflects the low sugars with equal accuracy. The estimated A1c is very reliable and can be used as a guiding in case of a discrepancy with the lab measured Hba1c
