Evaluation of Factors Affecting CGMS Calibration
Autor: | Andrea Kalajian, Katrina J. Ruedy, Larry A. Fox, Stuart A. Weinzimer, Roy W. Beck, Bruce A. Buckingham, Michael Tansey, Darrell M. Wilson, Craig Kollman, Rosanna Fiallo-Scharer, William V. Tamborlane |
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Rok vydání: | 2006 |
Předmět: |
Blood Glucose
medicine.medical_specialty Adolescent Endocrinology Diabetes and Metabolism Sensitivity and Specificity Gas Chromatography-Mass Spectrometry Article Endocrinology Internal medicine Calibration Humans Medicine Child Inpatients Extramural business.industry Continuous glucose monitoring Reproducibility of Results Circadian Rhythm Absolute deviation Medical Laboratory Technology Diabetes Mellitus Type 1 Reference values Exercise Test Nuclear medicine business |
Zdroj: | Diabetes Technology & Therapeutics. 8:318-325 |
ISSN: | 1557-8593 1520-9156 |
Popis: | The optimal number/timing of calibrations entered into the CGMS (Medtronic MiniMed, Northridge, CA) continuous glucose monitoring system have not been previously described.Fifty subjects with Type 1 diabetes mellitus (10-18 years old) were hospitalized in a clinical research center for approximately 24 h on two separate days. CGMS and OneTouch Ultra meter (LifeScan, Milpitas, CA) data were obtained. The CGMS was retrospectively recalibrated using the Ultra data varying the number and timing of calibrations. Resulting CGMS values were compared against laboratory reference values.There was a modest improvement in accuracy with increasing number of calibrations. The median relative absolute deviation (RAD) was 14%, 15%, 13%, and 13% when using three, four, five, and seven calibration values, respectively (P0.001). Corresponding percentages of CGMS-reference pairs meeting the International Organisation for Standardisation criteria were 66%, 67%, 71%, and 72% (P0.001). Nighttime accuracy improved when daytime calibrations (pre-lunch and pre-dinner) were removed leaving only two calibrations at 9 p.m. and 6 a.m. (median difference, -2 vs. -9 mg/dL, P0.001; median RAD, 12% vs. 15%, P = 0.001). Accuracy was better on visits where the average absolute rate of glucose change at the times of calibration was lower. On visits with average absolute rates0.5, 0.5 to1.0, 1.0 to1.5, andor=1.5 mg/dL/min, median RAD values were 13% versus 14% versus 17% versus 19%, respectively (P = 0.05).Although accuracy is slightly improved with more calibrations, the timing of the calibrations appears more important. Modifying the algorithm to put less weight on daytime calibrations for nighttime values and calibrating during times of relative glucose stability may have greater impact on accuracy. |
Databáze: | OpenAIRE |
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