The Up and Down Sides of Continuous Glucose Monitoring

Continuous glucose monitoring systems (CGMS) provide users with a nearly continuous readout of their blood sugar level.

By placing a long lasting sensor beneath the skin, CGMS measures the glucose in tissue fluid, the same watery ooze that escapes a burn or skin scrape. The glucose reading is radioed from the sensor’s connected transmitter to a pager-sized receiving device.

Although continuous monitoring can improve a diabetic’s health, it is not designed to make life more convenient. Some people find the information provided more valuable than the CGMS hassles. Others find the opposite true.

CGMS Advantages: Knowledge and Control

CGMS is marketed as a discreet way to view changing glucose values throughout the day without have to finger stick. Trend arrows on the monitor indicate whether glucose is on the rise, or falling. Most CGMS have alarms that warn users when their glucose is approaching a preset low or high limit. For some people, having this tighter control brings peace of mind.

It is also possible, with CGMS, to identify trends and blood sugar fluctuations that cannot be detected by finger stick or A1C measurements. For instance, continuous readings can reveal early morning glucose spikes, dangerously low overnight levels, or high blood sugar between meals. The effects of a person’s exercise and diet can be carefully evaluated using CGMS readings, and it gives medical teams excellent feedback about any changes made to treatment plans.

People who are willing to keep meticulous records of diet, medication, exercise, and CGMS data discover the triggers behind glucose management problems. They might uncover what provokes their liver to suddenly dump sugar into the blood stream, causing chaotic readings, or that the timing of their insulin needs adjusting.

Having more knowledge and control over glucose levels can make life easier or more secure in some ways, but acquiring this knowledge and control requires some discipline.

Possible Disadvantages: Calibration and Cost

Although CGMS readings do not need a finger stick, a few finger sticks are still required. To keep the continuous monitor calibrated it is necessary to check blood glucose levels two to four times each day. It is also recommended that treatment decisions are based on a CGMS reading plus a conventional blood glucose reading, and the two may differ.

There are sometimes significant differences (up to 15 percent) between sensor and finger stick readings. It takes glucose five or ten minutes to travel from the bloodstream into the tissue fluid. So, CGMS readouts might lag a bit behind quickly changing blood glucose levels.

To those who experience better health through CGMS, the daily calibrations, and sensor or finger stick readout differences are accepted as part of a beneficial process, but there is still the issue of cost. Though insurance may cover CGMS, some users find continuous monitoring too expensive.

The sensors usually last three to seven days, and though not difficult to insert they cost $35 to $100 each. (Sturdier sensors lasting more than three months are in development.) The transmitter battery, changed approximately once a year, is roughly $500, and the CGMS monitors can run from $1000 to $1400.

Source: Diabetes Self Management
Photo credit: Francisco Osorio / flickr.