A study sponsored by the Juvenile Diabetes Research Foundation confirms that many older type 1 patients achieve better control of their blood sugar levels by using a continuous glucose monitor (CGM) than by conventional monitoring with a meter and finger pricks.
The study also shows that the success of a CGM may depend on the age of the user.
CGMs use tiny sensors embedded under the skin to report blood glucose levels up to several hundred times a day. The data allow users to track upward and downward blood sugar trends, to which they can respond with exercise, insulin doses, or changes in food intake.
The study, published on September 8, 2008, in the New England Journal of Medicine, used CGMs from three manufacturers: Abbott Laboratories (Free Style Navigator), DexCom, Inc. (DexCom Seven), and Medtronic, Inc. (MiniMed insulin pump and CGM). Abbott and Johnson & Johnson supplied the home glucose meters.
Over six months, the study tracked 322 type 1s who were receiving intensive therapy in the form of either insulin pump use or more than three daily injections of insulin. The patients were divided into two groups: the first group, with 165 patients, used CGMs exclusively, while the second group of 157 patients used traditional home glucose meters and test strips.
The patients were further divided into three age groups: eight- to 14-year-olds (114 patients); 15- to 24-year-olds (110 patients); and those 25 years and older (98 patients).
By the end of the study, the 25 and older group saw a 0.53% reduction in average A1c. (The mean baseline A1c level for all study patients was 8%.)
The study reported no statistically significant reductions in A1c levels for the two younger patient groups. The researchers attributed these results to each group’s rate of use. In the 25 and older group, 83 percent of the patients used the CGM at least six days a week, compared to only 30 percent of the 15- to 24-year-old group.
Among the eight- to 14-year-old group, who might have been expected to record an even lower rate of use, 50 percent used the CGM six days or more per week. That figure may have resulted from greater parental involvement with younger patients.
The study’s results add more weight to the case for CGM reimbursement by insurance companies, an argument that manufacturers, physicians, and patients have been making for some time. By giving people with diabetes the tools to control their blood sugar levels, the insurance companies will pay less down the line to treat the retinopathy, vascular disease, and kidney problems that often result from uncontrolled blood sugar. In the long run, paying for CGMs will have a beneficial effect on insurance company profit margins.