HEALTHWATCH
Control diabetes on your own
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Dr.V. MOHAN assesses the importance of self-monitoring blood glucose by diabetic patients.
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It's now possible to monitor blood glucose at home.
ACCORDING to the latest WHO reports, India has over 32 million diabetic patients. According to our studies, 25 per cent of the patients develop diabetes-related complications, which are mostly due to poor diabetes control. Monitoring blood sugar levels at home is an essential component of diabetes management.
Diabetes affects both large blood vessels (heart, cerebral and peripheral) called macrovascular complications and small blood vessels (kidney, retina and nerves) called microvascular complications. Many complications are thought to be due to persistently high levels of blood glucose. It is now known that controlling blood glucose and blood pressure levels can minimise or prevent the onset of these complications.
Several studies have shown that any reduction in the glycated haemoglobin (HbA1c), which measures the patients' metabolic control during the preceding one to three months, is likely to reduce the risk of complications, with the lowest risk being in those with HbA1c values in the normal range ({lt}6%). In the Diabetes Control and Complication Trial (DCCT) it was clear that people who tested their blood glucose at home each day could significantly lower their risk of developing eye, kidney and nerve complications associated with diabetes.
Self-Monitoring of Blood Glucose (SMBG) started in the 1970s when it was first recommended as a useful tool to facilitate assessment of diabetes control at home in patients with Type One (insulin dependent) or Type 2 (non-insulin dependent) diabetes mellitus. But SMBG appears to be efficient only when it is integrated into a strategy of self-treatment, which implies that the patient modifies his/her behaviour and medicines (diet, exercise, oral anti-diabetic agents, insulin doses) to adjust the metabolic status according to his/her blood glucose measurements.
Indications and uses: SMBG helps monitor glycemic control at home, adjust treatment regimens as needed, and achieve near-normal blood glucose levels. A number of meters, (or monitors as they are called), have been developed to help people test their blood glucose in the comfort of their homes at any time of the day or night just using a drop of blood.
Benefits: SMBG helps evaluate the effectiveness of pharmacological therapy and the impact of dietary factors on glycemic control. It could help patients interpret and respond to blood glucose patterns, identify acute complications such as low blood glucose reactions — hypoglycemia ("unawareness") and very high sugar levels particularly a threat of ketoacidosis or diabetic coma.
The patient's SMBG data also helps the health care team to:
Identify trends in glucose control (prevent, confirm and avoid hypoglycemia and prevent hyperglycemia).
Identify factors that may cause fluctuations in glucose levels.
Evaluate the glycemic response to the effect of insulin.
Evaluate the impact of food, activity or medications.
Assess risk of later development of complications
Identify where changes in the treatment plan are mandatory.
Frequency: The frequency and timing of home blood glucose monitoring should be individualised, depending on the patient, his/her current glycemic control and the therapeutic regimen. The physician will recommend the number of times one has to monitor blood glucose levels a day depending on:
The stability of insulin therapy, blood glucose levels and diet management,
Nocturnal hypoglycemia,
Period of illness and stress
Changes in activity pattern.
Initially, one may need to check it several times a day. Once blood sugar stabilises, the frequency can be reduced. Generally, insulin-treated patients require more frequent monitoring (two or more times a day) compared to those not on insulin and if their HbA1c values are less than seven per cent.
Secondly, unstable (liable or brittle) diabetes requires more frequent monitoring than stable diabetes. In a patient whose HbA1c level is higher than seven per cent, monitoring of pre-prandial and post prandial blood glucose levels is necessary to alter the treatment regimen to reduce it to below seven per cent. Regardless of the type of diabetes or the therapy, frequent monitoring is one of the keys to optimal blood glucose control.
Reliability of monitors: This is a question patients often ask. This lack of trust partly stems from the fact that earlier meters were not very reliable, as the technology was not well developed. But things have changed considerably now. If the instructions are followed carefully, the results of SMBG are very accurate and reproducible. There will still be a 10-15 per cent variation between readings on meters and lab values. This is because meters test capillary whole blood glucose while lab tests are usually done on venous plasma samples (after blood cells are removed).
It is not necessary to compare the meter reading with a lab value. Instead set your own goals with the meter reading. Advances in technology are replacing traditional monitoring methods that require a big blood sample that deters people from checking their glucose levels as often as they should. Now only a quarter of a drop of blood is needed. With the minimally or non-invasive monitoring products becoming available, pain-free glucose monitoring is becoming a reality.
Factors affecting glucose meter performance
The accuracy and reliability of glucose monitoring meters depends on various factors including the quality of the meter, lack of calibration, lack of training, improper cleaning of the meters (dirt, blood stains etc.), poor quality of test strips (contaminated due to improper storage, usage after expiry date etc.) and insufficient/ excess quantity of blood on strip or exposure of the test strips inadvertently to humidity or extreme temperature. The modern meters have solved most of these problems.
Barriers to SMBG
IN the Chennai Urban Rural Epidemiological Study (CURES) conducted by the M.V. Diabetes Specialities Centre and the Madras Diabetes Research Foundation, Gopalapuram, Chennai, we found that only 0.001 per cent (i.e. 1 in 1000) of diabetic patients in Chennai did any form of SMBG. This is abnormally low compared to countries like the U.S. where majority of patients perform SMBG.
Recently we conducted another study to determine the reasons. Some of these are:
Cost of meter
Pain associated
with needle prick
Psychological
Lack of time
Lack of education
Cost of strips
The major factor seems to be the cost of meter. Most meters currently cost about Rs. 4,500 to 5,000. This situation would improve drastically if an inexpensive meter was produced.
Such meters are currently under development specifically for developing countries and one such prototype is to be launched soon in India. The pain associated with lancet pricks has been largely overcome.
Also the amount of blood withdrawn for SMBG has come down to a fraction of a drop. The meters have also become more efficient and it takes only five seconds to obtain the readings.
This is the only way to ensure tight control of diabetes and prevent the complications of diabetes in the millions of patients.
Self-monitoring: For whom?
Ideally all patients should monitor their own blood glucose levels using meters and test strips, which are now freely available.
All patients on insulin therapy, especially those on multiple dose regimens
Patients on oral hypoglycemic agents whose blood sugar and glycated hemoglobin are above normal
Patients with widely fluctuating blood glucose levels (brittle or unstable diabetes)
Patients prone to severe ketosis or recurrent hypoglycemia
Those manifesting hypoglycemic "unawareness"
Pregnant diabetic patients
Those with abnormal "renal thresholds" i.e. in whom urine glucose tests are unreliable( either show too much or too little sugar in the urine)
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