title: Poor agreement of computerized calculators for mean amplitude of glycemic excursions.
abstract: BACKGROUND
  Glucose variability has been identified as a predictor of hypoglycemia and has been associated with mortality in critically ill patients without diabetes. A popular metric to quantify glucose variability is the mean amplitude of glycemic excursions (MAGE). The "ruler and pencil" approach to calculate MAGE is operator-dependent and time-consuming for analysis of continuous glucose monitoring data. Therefore, several computer software programs have been developed for the automated calculation of MAGE. The aim of our study was to evaluate the agreement of currently available MAGE calculators when applied to the same set of continuous glucose monitoring (CGM) traces.
  
  
  METHODS
  Four software programs for calculation of MAGE were identified and used to calculate MAGE of 21 CGM traces from seven patients with type 1 diabetes. Subsequently, the median MAGE per calculator was calculated. The correlation between the MAGE calculators was evaluated by Spearman's correlation analysis. Between-group comparison was performed using analysis of variance.
  
  
  RESULTS
  The median MAGE (interquartile range) per calculator was 8.7 (7.1-10.7), 6.7 (5.5-8.6), 6.7 (5.2-8.6), and 5.8 (4.3-7.1), which was statistically different overall (P<0.001). The correlation coefficients between the calculators ranged from 0.787 to 0.999.
  
  
  CONCLUSIONS
  Available computer programs developed to calculate MAGE show varying agreement. Although software programs for the calculation of MAGE would seem attractive to assess glucose variability, their use has limitations by different outcomes, in the absence of a gold standard.
authors.affiliation: Department of Internal Medicine, Academic Medical Centre , Amsterdam, The Netherlands .
authors.forename: Marjolein K
authors.initials: MK
authors.lastname: Sechterberger
authors.forename: Yoeri M
authors.initials: YM
authors.lastname: Luijf
authors.forename: J Hans
authors.initials: JH
authors.lastname: Devries
mesh_terms: D000704:Analysis of Variance; D001786:Blood Glucose / Q000378:metabolism*; D015190:Blood Glucose Self-Monitoring / Q000379:methods*; D003627:Data Interpretation, Statistical; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D038321:Glycemic Index; D006801:Humans; D007003:Hypoglycemia / Q000517:prevention & control; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012984:Software
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human