title: Consistency of quantitative scores of hypoglycemia severity and glycemic lability and comparison with continuous glucose monitoring system measures in long-standing type 1 diabetes.
abstract: BACKGROUND
  In long-standing type 1 diabetes (T1D), loss of endogenous insulin secretion and glucose dysregulation can lead to severe hypoglycemia and associated complications. Here, we report the serial consistency and the correlation between different scores that characterize glucose dysregulation using self-monitoring of blood glucose (SMBG), in a cohort of T1D individuals being evaluated for transplant eligibility in Clinical Islet Transplantation Consortium trials.
  
  
  METHODS
  In total, 152 C-peptide-negative T1D subjects with at least one severe hypoglycemia episode in the prior year documented SMBG at enrollment and every 6 months until deemed ineligible or transplanted. SMBG was used to calculate the HYPO score, Lability Index (LI), and mean amplitude of glycemic excursion (MAGE). Additionally, a blinded continuous glucose monitoring system (CGMS) was worn for 72 h at enrollment and every 12 months.
  
  
  RESULTS
  In this cohort, LI was the most consistent (intraclass correlation coefficient=0.70) over time, followed by the HYPO score (0.51), with MAGE being the least consistent (0.36). Although MAGE and LI were highly correlated with each other, neither correlated with CGMS SD or glucose coefficient of variation (CV). Subjects spent a median of 97 min/day at <54 mg/dL using CGMS. The HYPO score correlated with CGMS time below 54 mg/dL and glucose CV.
  
  
  CONCLUSIONS
  The HYPO score and LI are more consistent than MAGE in patients with established T1D experiencing severe hypoglycemic events and may be especially useful both for identifying subjects experiencing the greatest difficulty in maintaining glycemic control and for longitudinal assessment of novel interventions.
authors: 1 Clinical Islet Transplant Program, Division of Endocrinology, University of Alberta , Edmonton, Alberta, Canada .
authors: Peter A
authors: PA
authors: Senior
authors: Melena D
authors: MD
authors: Bellin
authors: Rodolfo
authors: R
authors: Alejandro
authors: Jon W
authors: JW
authors: Yankey
authors: William R
authors: WR
authors: Clarke
authors: Julie C
authors: JC
authors: Qidwai
authors: Traci R
authors: TR
authors: Schwieger
authors: Thomas L
authors: TL
authors: Eggerman
authors: Mark A
authors: MA
authors: Robien
authors: Michael R
authors: MR
authors: Rickels
mesh_terms: D000328:Adult; D000368:Aged; D015190:Blood Glucose Self-Monitoring / Q000379:methods*; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications; D005260:Female; D006801:Humans; D007003:Hypoglycemia / Q000097:blood* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D055815:Young Adult
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