title: Stimulated urine C-peptide creatinine ratio vs serum C-peptide level for monitoring of β-cell function in the first year after diagnosis of Type 1 diabetes.
abstract: To determine if urine C-peptide/creatinine ratio is a useful tool for monitoring β-cell function in new-onset Type 1 diabetes.
  
  
  
  Data were obtained from a prospective immunomodulation study in people with Type 1 diabetes ≤ 3 months from diagnosis, with a standard mixed-meal tolerance test and measurement of urine C-peptide/creatinine ratio carried out at 0, 3, 6, 9 and 12 months. The change in the insulin-dose-adjusted HbA1clevel was also correlated with the change in serum/urine C-peptide level during the 12-month follow-up period.
  
  
  
  A significant reduction in urine C-peptide/creatinine ratio, measured after a mixed-meal, was reached at 9 months (-45.4%), whilst the reduction in stimulated serum C-peptide level reached significance after 3 months (-54.7%) in placebo-treated participants. Neither change in stimulated serum C-peptide nor change in urine C-peptide level correlated with each other, and nor did change in insulin-dose-adjusted HbA1clevel in the first 6 months, but all measures correlated significantly in the second half of the 12-month follow-up period.
  
  
  
  Mixed-meal-stimulated urine C-peptide/creatinine ratio was similar to, although less sensitive than, stimulated serum C-peptide level in monitoring β-cell function during the first year after diagnosis. Because the former is significantly less invasive, it warrants inclusion in further studies in Type 1 diabetes and may represent an attractive alternative outcome measure in cohort studies and in children.
authors.affiliation: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, UK. tatovicd@cardiff.ac.uk.
authors.forename: D
authors.initials: D
authors.lastname: Tatovic
authors.affiliation: Institute for Life Sciences, Swansea University, Swansea, UK.
authors.forename: S
authors.initials: S
authors.lastname: Luzio
authors.affiliation: Institute for Life Sciences, Swansea University, Swansea, UK.
authors.forename: G
authors.initials: G
authors.lastname: Dunseath
authors.affiliation: Department of Immunobiology, Faculty of Life Sciences and Medicine, King's College London, London, UK.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, UK.
authors.forename: M
authors.initials: M
authors.lastname: Alhadj Ali
authors.affiliation: Department of Immunobiology, Faculty of Life Sciences and Medicine, King's College London, London, UK.
authors.forename: M
authors.initials: M
authors.lastname: Peakman
authors.affiliation: Diabetes Research Group, Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, UK.
authors.forename: C M
authors.initials: CM
authors.lastname: Dayan
mesh_terms: D000328:Adult; D002096:C-Peptide / Q000097:blood* / Q000652:urine*; D003404:Creatinine / Q000652:urine*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000652:urine; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D050417:Insulin-Secreting Cells / Q000502:physiology*; D008297:Male; D062407:Meals; D008991:Monitoring, Physiologic / Q000379:methods*; D019518:Postprandial Period; D011384:Proinsulin / Q000627:therapeutic use; D013997:Time Factors; D016482:Urinalysis; D055815:Young Adult
chemical_list: D002096:C-Peptide; D011384:Proinsulin; D003404:Creatinine