Use of continuous glucose monitoring system in the management of severe hypoglycemia.

Background: Severe hypoglycemia can have a dramatic impact on daily life for people with diabetes. Hypoglycemia is quantifiable by the HYPO-Score derived from the frequency of severe hypoglycemia over a year and a component based on 4 weeks of glucose records. The latter gives a modified HYPO-Score as a short-term measure of hypoglycemia. We used a continuous glucose monitoring system (CGMS) in patients with severe hypoglycemia to assess if we could decrease hypoglycemia as measured by the modified HYPO-Score.

Methods: Sixteen type 1 diabetes subjects, 52.0 +/- 2.3 years old with a diabetes duration of 29.4 +/- 2.8 years having problematic hypoglycemia were enrolled. All used multiple daily insulin injections, and the glycosylated hemoglobin level was 8.4 +/- 0.3%. After a month of gathering hypoglycemia information for baseline modified HYPO-Score, subjects wore the CGMS for 2 months, and a modified HYPO-Score was repeated. To assess long-term benefit, CGMS was then discontinued for 3 months, and a final modified HYPO-Score was determined.

Results: The modified HYPO-Score decreased from 857 +/- 184 to 444 +/- 92 (P = 0.055) (intention-to-treat basis). Further analysis of the modified HYPO-Score when the CGMS was actually functioning showed it decreased from 857 +/- 184 to 366 +/- 86 (P = 0.023). Severe hypoglycemia episodes dropped from 16 at baseline to three when wearing the CGMS. The number of hypoglycemia episodes <3.0 mmol/L dropped from 8.6 +/- 1.5 to 4.7 +/- 0.9 (P = 0.01). Subjects expressed less fear of hypoglycemia with CGMS. In 11 who completed modified Final Month HYPO-Scores, the number of severe hypoglycemic events rose to six. At study end, 13 of 16 subjects elected to continue using the CGMS.

Conclusions: When the CGMS was worn and functioning there was a significant decrease in the modified HYPO-Score and number of hypoglycemic values <3.0 mmol/L.