HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wentholt, I. M. Articles by DeVries, J. H. Search for Related Content PubMed PubMed Citation Articles by Wentholt, I. M. Articles by DeVries, J. H. Social Bookmarking                What's this?

A Critical Appraisal of the Continuous Glucose–Error Grid Analysis

From the Academic Medical Center, Department of Internal Medicine, Amsterdam, the Netherlands

Address correspondence and reprint requests to I.M. Wentholt, MD, Department of Internal Medicine, Academic Medical Center, P.O. Box 22660, 1100 AD Amsterdam, Netherlands. E-mail: i.m.wentholt{at}amc.uva.nl

OBJECTIVE—There is no consensus on how to optimally assess the accuracy of continuous glucose sensors. We examined the continuous glucose–error grid analysis (CG-EGA) and compared it with classical accuracy assessment methods, using data from a previously reported study comparing two different continuous glucose sensors in type 1 diabetic patients.

RESEARCH DESIGN AND METHODS—Drift, delay, mean absolute difference (MAD), sensitivity, and specificity for detecting hypo- and hyperglycemia were calculated, and a Clarke error grid and a CG-EGA were constructed for both sensors, also including an examination of the influence of choosing different time intervals for paired sensor and reference glucose values.

RESULTS—For sensor II, there was a delay between blood glucose and sensed glucose (7.1 min, P < 0.001). Sensor II was more accurate than sensor I during hypo- and hyperglycemia (e.g., smaller MAD, P = 0.011 and P = 0.024, respectively; better sensitivity for detecting hypoglycemia, P = 0.018). Correction for the 7-min delay improved sensor II MAD with 2.2% in every range. In contrast, CG-EGA did not reveal a difference in accuracy between the sensors. Paradoxically, CG-EGA results for sensor II deteriorated when corrected for the delay. CG-EGA calculated with shorter time intervals resulted in worsening accuracy for both sensors.

CONCLUSIONS—CG-EGA did not detect differences in accuracy whereas conventional methods did. CG-EGA is time demanding; results are hard to interpret and seem to vary with chosen time intervals. At present, CG-EGA does not contribute to a combination of various established assessment methods.

Abbreviations: CG-EGA, continuous glucose–error grid analysis • EGA, error grid analysis • MAD, mean absolute difference • P-EGA, point–error grid analysis • R-EGA, rate–error grid analysis

CiteULike    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				G. J. Worsley, G. A. Tourniaire, K. E. S. Medlock, F. K. Sartain, H. E. Harmer, M. Thatcher, A. M. Horgan, and J. Pritchard Continuous Blood Glucose Monitoring with a Thin-Film Optical Sensor Clin. Chem., October 1, 2007; 53(10): 1820 - 1826. [Abstract] [Full Text] [PDF]

				W. L. Clarke, L. Gonder-Frederick, D. Cox, and B. Kovatchev A Critical Appraisal of the Continuous Glucose-Error Grid Analysis: Response to Wentholt et al. Diabetes Care, February 1, 2007; 30(2): 449 - 450. [Full Text] [PDF]

				I. M. Wentholt, J. B. Hoekstra, and J. H. DeVries A Critical Appraisal of the Continuous Glucose-Error Grid Analysis: Response to Clarke et al. Diabetes Care, February 1, 2007; 30(2): 450 - 451. [Full Text] [PDF]

				C. De Block, B. Manuel-y-Keenoy, L. Van Gaal, and P. Rogiers Intensive Insulin Therapy in the Intensive Care Unit: Assessment by Continuous Glucose Monitoring: Response to Radermecker Diabetes Care, December 1, 2006; 29(12): 2763 - 2764. [Full Text] [PDF]