Jothydev Kesavadev, MD
Jothydev@gmail.com
www.research.jothydev.com
Though diabetes has been described more than 5000 years ago, it is still a challenging metabolic disorder. Majority of patients even on regular treatment succumb to the complications of diabetes after 10-20 years of its onset. With increase in the longevity, more and more patients with diabetes are becoming elderly, which is an additional burden and challenge to the prevention of long term micro and macro vascular complications.

Historically urine examination for the presence of sugar used to be the test for diagnosis and follow up of diabetes patients. With the publication of landmark clinical trials like DCCT,UKPDS, Kumamoto etc., it has been observed that when the average HbA1c reaches 7 or above there is a gradual but steady increase in the onset of complications in diabetes. The benefits of home based regular self-monitoring of blood glucose has been proven beyond doubt both in type 1 and type 2 diabetes so as to reach the goals of therapy in individual subjects. The next major step in blood glucose monitoring is the emergence of Continuous Glucose Monitoring (CGM) Devices.

We started using CGMS way back in 2005. Initially it was only a research tool but gradually emerged as a routine in clinical diabetes care.  A conventional glucometer used by a patient will provide 4-8 sugar readings per day and will require finger pricks for the same. In contrast, the Continuous Glucose Monitoring device will provide close to 300 readings in 24 hours and the device can be worn continuously over a period of 1 week to several weeks which will provide trends in blood glucose in the form of graphs. The major advantage of a CGM is its accuracy to graphically demonstrate the presence of dangerously low sugars during the time the patient is sleeping;  a finding of significant clinical value since hypoglycaemia can predispose to arrhythmias and even acute coronary events.

There are various devices for Continuous Glucose Monitoring. Some of them are available as standalone devices and some of them along with insulin pumps. Ipro2 is a standalone device which can be placed on the abdomen ; a bio sensor needle is inserted with the tip in the interstitial fluid via a pain free mechanism. The sensor will record the values and the mechanism is with voltage getting converted into sugar values. The major drawback with interstitial fluid glucose values is a lag time between the interstitial fluid and the blood glucose value. But studies have shown interstitial fluid glucose values to be more accurate and predictive.

Realtime CGM devices will enable the patient to see for himself or herself the glucose values and also the trends. Real time devices like Guardian from Medtronic and Dexcom 7 from Dexcom (Roche is marketing in India) has also got the additional facilities of alert; it will give out an alarm well before an impending hypoglycaemia or a hyperglycaemia alerting the patient for interventions. CGM data will provide information on time spent in hypoglycaemia, percentage of time the patient is having normal sugars throughout the days and nights of monitoring etc etc. The data from a CGM has to be interpreted with the clinical history of the subject, presence or absence of other co-morbid illnesses and data on his exercise, diet, sleep etc etc.

Our centre is one of the pioneers in research as well as clinical use of CGM in India. We have several national and international publications and presentations on Continuous Glucose Monitoring. One oral presentation at the prestigious American Diabetes Association is on the correlation of Continuous Glucose Monitoring data and how it can be used for modifications in the life styles of the individuals for fine tuning of blood glucose values without making any changes in the treatment regimen.

CGM can unravel glycemic patterns, hitherto undetected in routine SMBG. This makes it useful as a routine investigation to make concrete treatment decisions in diabetes patients on insulin. This finding of ours was presented at American Diabetes Association Scientific Sessions last year.
Due to the profound impact on lifestyle & drugs, CGM is highly acceptable as routine investigation in diabetes where 97% of the patients opted to repeat CGM as a routine tool. This study from our centre was widely discussed in the Advanced Technologies and Treatments for Diabetes (ATTD) Conference this year at Barcelona. Our study presented last year at ATTD at United Kingdom has also proved CGM as a tool for therapeutic decision making in diabetes patients. (www.research.jothydev.com)

In the coming years the CGM devices are likely to become more popular, cheap and more accurate gradually replacing the glucometers.  Despite several advantages of using a CGM, the major limitations will be the time spent for educating and motivating a patient and requirement of a skilled diabetes multidisciplinary team for performing the CGM and interpreting and preparing a detailed report.