Dear Editor:
I
n his letter, Dr. Blevins
1
points out that our study
2
of short-term blinded continuous glucose monitoring (CGM) using iPro™ (Medtronic, Northridge, CA) technology lacked standardization of the timing of hemoglobin A1c (glycoA1c) measurements pre- and post-CGM testing. In response, we extracted data from the 35 subjects whose glycoA1c measurements conform to the time frame suggested by Dr. Blevins, specifically, 2– 4 weeks prior to and no more than 4 months after CGM testing. In this group the mean±SD glycoA1c level before iPro CGM was 7.9±0.9% and after testing was 7.8±1.1%, values that are not statistically different, a result in agreement with the full group analysis.
We believe medical devices intended for office use must provide results robust enough to be evident in the hands of a diverse group of qualified practitioners, a condition satisfied by our single-specialty endocrinology practice. It is our conclusion that 3 days of blinded CGM using the iPro device in an office setting is unlikely to satisfy the goal of improving glycemic control as reflected by glycoA1c levels. We are in agreement with others
3,4
that protocols using monitoring of longer duration with unblinded CGM technology are more likely to provide the desired result.
