Managing diabetes is all about maintaining healthy blood glucose levels particularly after a meal or exercise. Glucose levels in people with diabetes can fluctuate between low, normal and dangerous. Tracking sugar levels, especially through continuous glucose monitoring devices helps in better management of diabetes and also helps to prevent or delay diabetes-related complications such as kidney disease, heart attack, stroke or even blindness.
“Monitoring is one of the five important aspects of diabetes management along with diet, exercises, medication and awareness,” says Dr Praveen Gangadhara, consultant, Dr Mohan’s Diabetes Specialities Centre, Bengaluru. “It is essential to identify the changes in blood glucose levels. It helps in achieving the desired glycaemic targets.”
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Self-monitoring of blood glucose level
A decade ago, diabetics had to visit hospitals or labs to check their blood glucose levels. Despite labs being technically advanced, Dr Gangadhara says lab tests may have some limitations and may not give accurate HbA1c (a test that measures the amount of blood sugar attached to the hemoglobin), fasting and postprandial blood sugar readings. “While two persons may have the same HbA1c reading they could have fluctuations in blood glucose levels (also called glycemic variability),” he says. “This is where having a glucose monitor at home can help you check your glycemic readings and maintain a record of them to inform your treating doctor on your health checkups.”
Self-monitoring devices like a glucometer is easy to handle, making it easy for people to read blood sugar levels on their own. “Self-monitoring of blood glucose (SMBG) is especially important for insulin-treated patients to monitor and prevent asymptomatic hypoglycaemia (low blood sugar) and hyperglycaemia (high blood sugar),” says Dr Gangadhara.
According to the US Food and Drug Administration (FDA), the Diabetes Control and Complications Trial (1993) showed that good glucose control using home monitors led to fewer disease complications.
Advanced glucose monitoring devices
The two common types of self-monitoring devices for glucose checking are the basic blood glucose meter and the continuous glucose monitor. Both these types are portable and can be carried comfortably while travelling, making it easy to keep track of readings while on the move.
Blood glucose meter
This handy device comes with its own set of lancets or pens with a needle. The lancet is used to prick the finger quickly to get a drop of blood. The blood droplet is placed on a disposable test strip which is inserted in the meter. This test strip contains chemicals that react with glucose in the blood to give an accurate reading.
There are different types of blood glucose meters that either measure the amount of electricity that passes through the test strip or the amount of light that reflects from it.
Chennai-based educationist Smriti Prabhakar (58), who had gestational diabetes during pregnancy, was diagnosed with diabetes when she was 50. She has been able to keep her blood sugar level under control merely by monitoring it at home on a blood glucose meter which her doctor taught her to use.
“I’ve been using the blood glucose meter at home for the last eight years and it has always given me accurate readings,” she says. “I use it once in three or four days to check my fasting or postprandial glucose levels.”
Continuous glucose monitoring system (CGMS)
This does not require pricking of the skin for blood. Instead, it measures blood glucose results of fluid in tissues on a continuous basis. Here, a disposable glucose sensor is placed under the skin. A link from the sensor to a transmitter or recording device worn on the body — on the arm, the thigh or abdomen — transfers the data to a synced device such as a smartphone. It records blood sugar trends and patterns throughout the day as well as night.
“CGM is advised in patients with type 1 diabetes, those having too many sugar fluctuations, during pregnancy, patients on insulin, and those who are having high HbA1c,” says Dr Ami Sanghvi, Mumbai-based consultant diabetologist. “CGM is also need-based. If the blood sugar levels are stable and the diabetic is comfortable, they might not require continuous monitoring.”
Prarthana Hegde, a technical sales engineer based in San Francisco who was diagnosed with type 1 diabetes just before she turned 25, says wearing a CGM device through the day and night gives her peace of mind.
“Initially I used to monitor my sugar levels using finger pricks and pen injections to administer insulin,” says Hegde, who is 29 now. “Two years down the line I joined a company whose insurance policy covered a CGMS. My doctor believed that I could manage my blood sugar levels better if I used a CGM. There were a bunch of CGM models that were available in the US that were paired with an insulin pump and I went in for one.”
Hedge says she has been using a CGM device for a little over three years. “Compared to the basic glucose meter where I had to use a finger prick and administer insulin when needed, with the CGM I prick once when I wake up and again before bed,” she says. “The best part about the CGM is my blood sugar is monitored every five minutes. The CGM samples the tissue fluid instead of the blood. It auto generates the report to my smartphone,” she adds.
While wearing the CGM, the person can continue normal activities without the need to stop to check the readings. The device provides real-time information about current blood glucose, short-term feedback about the effectiveness of diabetes interventions, and sends alerts about hypoglycemia or hyperglycemia. Some devices come programmed with apps where the readings can be checked on a smartphone.
“Importantly, my CGM helps me know the trend of how my blood sugar has been the whole day,” Prarthana says. “It auto-generates daily reports so I can keep a tab on it every 7, 14, 30 to 90 days. So, even if I get the data to my sugar levels for 30 days for every five minutes, it can predict how my A1c will look like. What’s more, equipped with these trend reports, I know when to adjust my insulin dosage.”
Citing a recent experience when her report showed a daily spike in her blood sugar between 10am and 12 pm, the young engineer says her doctor was puzzled with the readings. “I explained that I had coffee and gave myself a micro dose of insulin,” she says. “But the doctor found that was ineffective and increased the insulin dosage. This is how the CGM gives important analyses to take prompt action.”
Having synced her CGM to her insulin pump and smartphone, and configured it to a setting of 50-180 mg/dL, she says that even if her phone is on mute when she’s fast asleep, it beeps loudly to warn her when she is hypoglycemic so she can wake up and take glucose tablets or a glucose drink to prevent a blackout.
“Since my insulin pump has an auto-correct feature, it releases a micro-dose of insulin whenever it detects hyperglycemia,” she says. “Diabetes management is tighter with a CGM because you know your blood sugar levels at all times, every single day. It helps me adjust my insulin dose and bring down my A1c which is so beneficial for my long-term health.”
Prick vs tech: Needles and monitors
Technology is a great differentiator when it comes to glucose monitors too. As more advanced devices come into the market, diabetics as well as doctors who prescribe the monitors need to be up to date with the benefits and how they can be used appropriately.
Dr Kavitha Bhat, senior consultant, paediatric endocrinology, Aster Hospitals, Bengaluru, underlines the difference. “BGM provides a glucose value for the specific point in time when a blood drop is read, whereas CGM gives you a more complete picture of where your glucose is going, and where your glucose has been, so you can make more informed treatment decisions,” she says. “Think of glucose readings as the cars of a train, where the front of the train is blood glucose and the back of the train is sensor glucose. Because glucose enters the bloodstream first, blood glucose readings lead sensor glucose readings. Eventually, sensor glucose readings catch up to blood glucose readings just like the back of the train following the front of the train. The insights from CGM can help you figure out what has triggered a spike or a drop in glucose levels, such as exercise or something you ate.”
Importance of monitors for kids
CGMS is highly useful for schoolgoing children with diabetes who prefer to be monitored unobtrusively.
“Parents need to check their child’s blood sugar levels several times in a day,” says Dr Bhat. “This can be with a glucometer or a continuous glucose monitor.”
Managing blood sugar levels at home
Dos and Don’ts for managing blood sugar at home
- Understand the type of glucose monitors available and how to use them before selecting one.
- Read the user manual provided with the device and follow all the guidelines. Diabetes centres and doctors have trained personnel who teach diabetics on the appropriate use of the devices, so opt for a session
- Wash your hands thoroughly, dry them, and use the first drop of blood if you’re using the glucometer
- Use a fresh lancet every time you prick your finger. Lancets can get blunt and cause pain if you reuse them. They could also give inaccurate results
- Choose the correct lancet size depending on the thickness of your skin
- Ensure you check the expiry date on the test strips before using them. Using expired test strips can result in wrong readings
- While most strips can be used for three to six months, check the information in the user manual for correct usage time range
- The test strips are delicate and contain enzymes that analyse the blood drop. Ensure the strips are stored in a closed container away from direct heat and moisture
- Most importantly, change the device batteries every three months at least for accurate readings. Bluetooth synced monitors consume more energy and might have to be replaced sooner
- While wearing a wearable monitor like the CGM, ensure the filament that is inserted in your body does not get bent or damaged while you undertake strenuous activities. A damaged filament can affect the readings.
- Follow your doctor’s advice since they could point out which model is best for you depending on whether you have type 1 or type 2 diabetes.
(Source: Dr Praveen Gangadhara, Consultant, Dr Mohan’s Diabetes Specialities Centre, Bengaluru)
