title: Continuous glucose monitoring after islet transplantation in type 1 diabetes: an excellent graft function (β-score greater than 7) Is required to abrogate hyperglycemia, whereas a minimal function is necessary to suppress severe hypoglycemia (β-score greater than 3).
abstract: BACKGROUND
  For the last 10 yr, continuous glucose monitoring (CGM) has brought up new insights into the accuracy of blood glucose analysis.
  
  
  OBJECTIVE
  Our objective was to determine how islet graft function was able to influence the various components of dysglycemia after islet transplantation (IT).
  
  
  METHODS
  We conducted a single-arm open-labeled study with a 3-yr follow-up in a referral center (ClinicalTrial.gov identifiers NCT00446264 and NCT01123187).
  
  
  METHODS
  Twenty-three consecutive patients with type 1 diabetes (14 islet alone, nine islet after kidney) received IT within 3 months using the Edmonton protocol.
  
  
  METHODS
  INTERVENTION included 72-h CGM before and 3, 6, 9, 12, 24, and 36 months after transplantation.
  
  
  METHODS
  Graft function was estimated via β-score, a previously validated index (range 0-8) based on treatment requirements, C-peptide, blood glucose, and glycated hemoglobin.
  
  
  RESULTS
  At the 3-yr visit, graft function persisted in 19 patients (82%), and 10 (43%) remained insulin independent. Glycated hemoglobin decreased in the whole cohort from 8.3% (7.3-9.0%) at baseline to 6.7% (5.9-7.7%) at 3 yr [median (interquartile range), P < 0.01]. Mean glucose, glucose sd, and time spent with glycemia above 10 mmol/liter (hyperglycemia) and below 3 mmol/liter (hypoglycemia) were significantly lower after IT (P < 0.05 vs. baseline). The four CGM outcomes were related to β-score (P < 0.001). However, partial function (β-score >3) was sufficient to abrogate hypoglycemia; suboptimal function (β-score >5) was necessary to significantly improve mean glucose, glucose sd, and hyperglycemia; and optimal function (β score >7) was necessary to normalize them.
  
  
  CONCLUSIONS
  The four components of dysglycemia were not equally affected by the degree of islet graft function, which could have important implications for future development of β-cell replacement. A β-score above 3 dramatically reduced the occurrence of hypoglycemia.
authors.affiliation: Endocrinologie et Métabolisme, hôpital Huriez, Institut National de la Santé et de la Recherche Médicale Unité 859, Centre Hospitalier et Universitaire de Lille, 1 rue Polonovski, F-59045 Lille, France. mc-vantyghem@chru-lille.fr
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Vantyghem
authors.forename: Violeta
authors.initials: V
authors.lastname: Raverdy
authors.forename: Anne-Sophie
authors.initials: AS
authors.lastname: Balavoine
authors.forename: Frédérique
authors.initials: F
authors.lastname: Defrance
authors.forename: Robert
authors.initials: R
authors.lastname: Caiazzo
authors.forename: Laurent
authors.initials: L
authors.lastname: Arnalsteen
authors.forename: Valéry
authors.initials: V
authors.lastname: Gmyr
authors.forename: Marc
authors.initials: M
authors.lastname: Hazzan
authors.forename: Christian
authors.initials: C
authors.lastname: Noël
authors.forename: Julie
authors.initials: J
authors.lastname: Kerr-Conte
authors.forename: Francois
authors.initials: F
authors.lastname: Pattou
mesh_terms: D000328:Adult; D001786:Blood Glucose / Q000032:analysis*; D015190:Blood Glucose Self-Monitoring; D002096:C-Peptide / Q000097:blood; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000601:surgery*; D007003:Hypoglycemia / Q000097:blood / Q000601:surgery*; D016381:Islets of Langerhans Transplantation / Q000379:methods*; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D001786:Blood Glucose; D002096:C-Peptide; D006442:Glycated Hemoglobin