New self-monitoring devices are a boon to diabetics

New devices that provide continuous glucose monitoring should be a boon for diabetics. But using them correctly takes self-discipline

PUBLISHED : Monday, 20 May, 2013, 12:00am
UPDATED : Monday, 20 May, 2013, 9:45am

When Tsiang Chi-tsing was diagnosed as diabetic five years ago, he stuck to a self-testing regime of using a fingerstick to measure his blood glucose levels three times a week. But after six months, his self-discipline sagged due to overwhelming work and family duties.

"The doctor told me to measure the blood glucose levels on an empty stomach, and after meal, at least three times a week. But I was so busy at work that I always forgot. Plus, I forgot to take the fingerstick with me on family outings."

His lax discipline has had consequences. Tsiang, the 70-year-old owner of a food store, has since developed high uric acid levels and high blood pressure. "When I first got my diagnosis, I just needed to take one pill a day. Now I have to take eight. The doctor said I should have done better in self-monitoring and changing my diet."

Tsiang's deterioration illustrates the importance of self-monitoring blood glucose levels for diabetic patients. Specialists in endocrinology, diabetes and metabolism say the introduction of new self-monitoring devices can help patients and doctors control the condition better.

To use the new continuous glucose monitoring system device, a patient pricks himself in the finger to obtain blood for a test, which uses a blood glucose meter to manage diabetes day by day. There is also a haemoglobin A1c test, which shows a patient's average blood glucose levels over the past three months by providing readings of daily blood glucose levels.

The doctor said I should have done better in self-monitoring and changing my diet
Tsiang Chi-tsing, diabetes sufferer

The device, a continuous glucose monitoring system, inserts a tiny tube underneath the patient's abdominal skin, which is connected to a small blood glucose sensor.

The sensor measures the level of glucose in the tissue every five minutes, day and night, for up to a week. Medical personnel then remove it, and the blood glucose level readings are downloaded onto a computer for analysis.

Norman Chan, a specialist in endocrinology, diabetes and metabolism, says the device, which costs HK$2,000 and is used in public hospitals, is particularly useful for those who have serious forms of diabetes.

"The device can record 288 bits of data per day. It records the trend of blood glucose levels throughout the day. But a fingerstick or A1c test can only show blood glucose levels at a particular time, without showing the rise and falls in levels throughout the day," Chan says.

For those patients who have developed complications like diabetic eye problems and kidney failure, a detailed recording can help the doctor prescribe treatment to prevent the condition from worsening.

"Pregnant women suffering from gestational diabetes are also ideal users, as poorly controlled diabetes will affect fetal development," Chan says.

There are 700,000 diabetics in the city, and fingerstick tests are a daily ritual for many. Chan says local research showed that 40 per cent of patients with normal fingerstick readings were shown to have high blood glucose levels after a meal, and low blood glucose levels at night. "It showed that the fingerstick cannot show the changing patterns of the levels every day. There was a male patient who stuck to his doctor's advice and got normal fingerstick readings every day. But the effects of his diabetes progressed to his eye.

"His later use of the continuous device showed that he had a low blood glucose level at night. So his doctor prescribed corresponding treatment and his condition was under control afterwards," says Chan.

Chan did some research on the use of the device, in which 28 patients suffering from type-one and type-two diabetes, who are receiving insulin injections, were involved. They wore the device for six days.

"The research showed that the patients had low blood glucose levels for an average of 42 per cent of the time they were asleep. Five patients were showed to display low levels for 30 per cent of the time during sleep. Low blood glucose levels, if left untreated, can have serious complications like poorer cognitive functions or lapsing into a coma."

Ronald Ma Ching-wan, professor with Chinese University's department of medicine and therapeutics, and former president of Diabetes Hongkong, says that while the device can provide detailed readings, it cannot replace the traditional fingerstick check-ups.

"You can't be lazy and wear the device once a year and skip the fingerstick tests," he says. "The device provides only a snapshot of the condition for a couple of days. Patients wearing the device should still do the fingerstick tests."