title: Home urine C-peptide creatinine ratio can be used to monitor islet transplant function.
abstract: OBJECTIVE
  Islet graft function is defined by serum C-peptide in a standardized challenge test. We assessed whether urine C-peptide creatinine ratio (UCPCR) sent from home could provide a viable alternative.
  
  
  METHODS
  Seventeen islet recipients provided 90-min serum C-peptide (sCP90) and 120-min UCPCR (UCPCR120) samples during 68 interval posttransplant mixed-meal tolerance tests, also posting from home a 120-min postbreakfast UCPCR sample every 2 weeks. UCPCR was compared with a clinical score of islet function, derived from HbA1c and insulin dose.
  
  
  RESULTS
  UCPCR120 and mean home postmeal UCPCR were strongly correlated with sCP90 (r(s) = 0.73, P < 0.001; and rs = 0.73, P < 0.01, respectively). Mean home UCPCR increased with clinical score (r(s) = 0.75; P < 0.001) and with graft function defined both by sCP90 >200 pmol/L and insulin independence. UCPCR cutoffs to detect insulin independence and poor graft function were sensitive and specific.
  
  
  CONCLUSIONS
  Home UCPCR provides a valid measure of C-peptide production in islet transplant recipients.
authors.affiliation: NIHR Exeter Clinical Research Facility, Exeter Medical School, U.K.
authors.forename: Richard A
authors.initials: RA
authors.lastname: Oram
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle, U.K.
authors.forename: Augustin M
authors.initials: AM
authors.lastname: Brooks
authors.affiliation: Royal Infirmary of Edinburgh and Endocrinology Unit, University of Edinburgh, Edinburgh, U.K.
authors.forename: Shareen
authors.initials: S
authors.lastname: Forbes
authors.affiliation: Richard Bright Renal Unit, Southmead Hospital, Bristol, U.K.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Eckoldt
authors.affiliation: Richard Bright Renal Unit, Southmead Hospital, Bristol, U.K.
authors.forename: Richard M
authors.initials: RM
authors.lastname: Smith
authors.affiliation: Diabetes Research Group, King's College London, London, U.K.
authors.forename: Pratik
authors.initials: P
authors.lastname: Choudhary
authors.affiliation: Diabetes Service Royal Free London NHS Foundation Trust, U.K.
authors.forename: Miranda J
authors.initials: MJ
authors.lastname: Rosenthal
authors.affiliation: Oxford Centre for Diabetes Endocrinology and Metabolism, University of Oxford, Oxford, U.K.
authors.forename: Paul
authors.initials: P
authors.lastname: Johnson
authors.affiliation: Endocrinology and Diabetes Research Group, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, Manchester, U.K.Manchester Diabetes Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, U.K.
authors.forename: Martin K
authors.initials: MK
authors.lastname: Rutter
authors.affiliation: NIHR Cambridge Biomedical Research Centre, Core Biochemical Assay Laboratory, Cambridge, U.K.
authors.forename: Keith A
authors.initials: KA
authors.lastname: Burling
authors.affiliation: NIHR Exeter Clinical Research Facility, Exeter Medical School, U.K.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: McDonald
authors.affiliation: Institute of Cellular Medicine, Newcastle University, Newcastle, U.K. a.t.hattersley@ex.ac.uk jim.shaw@ncl.ac.uk.
authors.forename: James A M
authors.initials: JA
authors.lastname: Shaw
authors.affiliation: NIHR Exeter Clinical Research Facility, Exeter Medical School, U.K. a.t.hattersley@ex.ac.uk jim.shaw@ncl.ac.uk.
authors.forename: Andrew T
authors.initials: AT
authors.lastname: Hattersley
mesh_terms: D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000652:urine; D002096:C-Peptide / Q000097:blood / Q000652:urine*; D003404:Creatinine / Q000097:blood / Q000652:urine*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000601:surgery / Q000652:urine*; D005260:Female; D005500:Follow-Up Studies; D006085:Graft Survival / Q000502:physiology*; D006801:Humans; D050417:Insulin-Secreting Cells / Q000502:physiology*; D016381:Islets of Langerhans Transplantation; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D011379:Prognosis; D011446:Prospective Studies
chemical_list: D015415:Biomarkers; D002096:C-Peptide; D003404:Creatinine