title: Can continuous glucose monitoring systems predict glycemia?
abstract: BACKGROUND
  We investigated whether the arrow on a continuous glucose monitoring system (CGMS) screen predicts the course of the capillary glucose level 15 min later.
  
  
  METHODS
  Twenty-three patients with type 1 diabetes (age, 40±13 years; diabetes duration, 19±12 years; hemoglobin A1c, 8.5±1.5%) admitted for education in the use of a CGMS performed 242 observations: the arrow was noted at time 0, and the interstitial and capillary glucose levels were noted at time 0 and 15 min later.
  
  
  RESULTS
  The capillary glucose courses were -15±28 mg/dL after a descending arrow (n=55), +1±23 mg/dL after a stable arrow (n=147) (P<0.001 vs. descending), and +2±23 mg/dL after an ascending arrow (n=40) (P<0.01 vs. descending), with similar findings for the 67 observations after an interstitial glucose level <100 mg/dL. There were 4.5% grossly erroneous arrows: six descending with later increasing and five ascending with later decreasing capillary glucose.
  
  
  CONCLUSIONS
  Although there is a large room for improvement, the arrow on the CGMS screen does predict the decline in capillary glucose 15 min later.
authors.affiliation: University of Bordeaux 2-Victor Segalen, Bordeaux, France.
authors.forename: Concepcion
authors.initials: C
authors.lastname: Gonzalez
authors.forename: Elisa
authors.initials: E
authors.lastname: Maury
authors.forename: Isabelle
authors.initials: I
authors.lastname: Barcos
authors.forename: Henri
authors.initials: H
authors.lastname: Gin
authors.forename: Vincent
authors.initials: V
authors.lastname: Rigalleau
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D015190:Blood Glucose Self-Monitoring; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007003:Hypoglycemia / Q000097:blood*; D008297:Male; D008991:Monitoring, Physiologic / Q000379:methods*; D010353:Patient Education as Topic; D011237:Predictive Value of Tests; D015203:Reproducibility of Results
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human