Continuous Glucose Sensors Are the Best Way to Trend Glucose Analyses

A comparative study of two currently available subcutaneous glucose sensors — the needle-type CGMSgold sensor and the microdialysis-based GlucoDay sensor — suggests that both are valuable adjunctive tools for analyzing trends in glucose control.

Dr. Iris M. Wentholt from Academic Medical Center, Amsterdam, the Netherlands stated, “That because of the considerable mean absolute differences (MADs) between sensor and blood glucose values, “individual sensor readings should be interpreted with caution.”

Dr. Wentholt and colleagues examined the reliability of the CGMSgold sensor from Medtronic Mini-Med, Sylmar, CA, and the GlucoDay sensor from Menarini Diagnostics, Firenze, Italy, at night and during rapid glucose excursions in 13 type 1 diabetic patients.

Based on the MADs — a measure for accuracy compared to a reference value — the GlucoDay sensor is significantly more accurate than the CGMSgold sensor, the investigators found. “Nevertheless, MADs were still considerable for both sensors, with a MAD of 15.0% for the CGMSgold and 13.6% for the GlucoDay sensor,” Dr. Wentholt said.

“We also found — after calculating the MAD per glucose range — that accuracy clearly deteriorated in the hypoglycemic range, especially for the CGMSgold sensor with a MAD of 24% in that range,” Dr. Wentholt noted.

The study also shows that CGMSgold sensor, which is available both in Europe and the United States, no longer shows a tendency to report lower glucose values during the night, in contrast to an earlier version of this sensor. “So, in this respect it has improved,” Dr. Wentholt said.

The GlucoDay sensor, on the other hand, which is only available in Europe, “has a significant delay of seven minutes on average upon blood glucose values. This delay can be corrected for retrospectively but has implications for online use of the sensor as a hypo- or hyperglycemic alarm,” Dr. Wentholt pointed out.

Diabetes Care 2005;28:2871-2876.