PMID- 29860430 OWN - NLM STAT- MEDLINE DCOM- 20190514 LR - 20220129 IS - 1945-7197 (Electronic) IS - 0021-972X (Print) IS - 0021-972X (Linking) VI - 103 IP - 9 DP - 2018 Sep 1 TI - Frequent Monitoring of C-Peptide Levels in Newly Diagnosed Type 1 Subjects Using Dried Blood Spots Collected at Home. PG - 3350-3358 LID - 10.1210/jc.2018-00500 [doi] AB - OBJECTIVE: To evaluate an approach to measure beta-cell function by frequent testing of C-peptide concentrations in dried blood spots (DBSs). PATIENTS: Thirty-two children, aged 7 to 17 years, with a recent diagnosis of type 1 diabetes. DESIGN: Mixed-meal tolerance test (MMTT) within 6 and again at 12 months after diagnosis, with paired venous and DBS C-peptide sampling at 0 and 90 minutes. Weekly DBS C-peptide before and after standardized breakfasts collected at home. RESULTS: DBS and plasma C-peptide levels (n = 115) correlated strongly (r = 0.91; P < 0.001). The Bland-Altman plot indicated good agreement. The median number of home-collected DBS cards per participant was 24 over a median of 6.9 months. Repeated DBS C-peptide levels varied considerably within and between subjects. Adjustment for corresponding home glucose measurements reduced the variance, permitting accurate description of changes over time. The correlation of the C-peptide slope over time (assessed by repeated home DBS) vs area under the curve during the two MMTTs was r = 0.73 (P < 0.001). Mixed models showed that a 1-month increase in diabetes duration was associated with 17-pmol/L decline in fasting DBS C-peptide, whereas increases of 1 mmol/L in glucose, 1 year older age at diagnosis, and 100 pmol/L higher baseline plasma C-peptide were associated with 18, 17, and 61 pmol/L higher fasting DBS C-peptide levels, respectively. In addition, glucose responsiveness decreased with longer diabetes duration. CONCLUSION: Our approach permitted frequent assessment of C-peptide, making it feasible to monitor beta-cell function at home. Evaluation of changes in the slope of C-peptide through this method may permit short-term evaluation of promising interventions. FAU - Willemsen, Ruben H AU - Willemsen RH AD - University of Cambridge, Department of Paediatrics, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom. AD - Department of Paediatric Diabetes and Endocrinology, Royal London Hospital, Barts Health NHS Trust, London, United Kingdom. FAU - Burling, Keith AU - Burling K AD - NIHR Cambridge Biomedical Research Centre, Core Biochemistry Assay Laboratory, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom. FAU - Barker, Peter AU - Barker P AD - NIHR Cambridge Biomedical Research Centre, Core Biochemistry Assay Laboratory, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom. FAU - Ackland, Fran AU - Ackland F AD - Paediatrics, Northampton General Hospital NHS Trust, Northampton, United Kingdom. FAU - Dias, Renuka P AU - Dias RP AD - Department of Paediatric Endocrinology and Diabetes, Birmingham Children's Hospital NHS Foundation Trust, Steelhouse Lane, Birmingham, United Kingdom. AD - Institutes of Metabolism and Systems Research, Vincent Drive, University of Birmingham, Birmingham, United Kingdom. AD - Centre for Endocrinology, Diabetes and Metabolism, Vincent Drive, Birmingham Health Partners, Birmingham, United Kingdom. FAU - Edge, Julie AU - Edge J AD - Paediatric Endocrinology, Oxford Radcliffe Hospitals NHS Trust, Headington, Oxford, United Kingdom. FAU - Smith, Anne AU - Smith A AD - Paediatrics, Northampton General Hospital NHS Trust, Northampton, United Kingdom. FAU - Todd, John AU - Todd J AD - JDRF/Wellcome Trust Diabetes and Inflammation Laboratory, Wellcome Trust Centre for Human Genetics, Nuffield Department of Medicine, NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, United Kingdom. FAU - Lopez, Boryana AU - Lopez B AD - University of Cambridge MRC Biostatistics Unit Hub for Trials Methodology Research, Cambridge, United Kingdom. FAU - Mander, Adrian P AU - Mander AP AD - University of Cambridge MRC Biostatistics Unit Hub for Trials Methodology Research, Cambridge, United Kingdom. FAU - Guy, Catherine AU - Guy C AD - University of Cambridge, Department of Paediatrics, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom. FAU - Dunger, David B AU - Dunger DB AD - University of Cambridge, Department of Paediatrics, Cambridge University Hospitals NHS Foundation Trust, Cambridge Biomedical Campus, Cambridge, United Kingdom. AD - Wellcome Trust MRC Institute of Metabolic Science, Cambridge, United Kingdom. LA - eng GR - WT091157/107212/WT_/Wellcome Trust/United Kingdom GR - MC_UU_00002/3/MRC_/Medical Research Council/United Kingdom GR - WT083650/Z/07/Z/WT_/Wellcome Trust/United Kingdom GR - Wellcome Trust/United Kingdom GR - MC_UU_12012/5/MRC_/Medical Research Council/United Kingdom PT - Evaluation Study PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - United States TA - J Clin Endocrinol Metab JT - The Journal of clinical endocrinology and metabolism JID - 0375362 RN - 0 (Blood Glucose) RN - 0 (C-Peptide) SB - IM MH - Adolescent MH - Area Under Curve MH - Blood Glucose/*analysis MH - Blood Glucose Self-Monitoring/*statistics & numerical data MH - C-Peptide/*blood MH - Child MH - Correlation of Data MH - Diabetes Mellitus, Type 1/*blood MH - Dried Blood Spot Testing/methods/*statistics & numerical data MH - Fasting/blood MH - Feasibility Studies MH - Female MH - Humans MH - Male MH - Time Factors PMC - PMC6126892 EDAT- 2018/06/04 06:00 MHDA- 2019/05/15 06:00 PMCR- 2018/05/31 CRDT- 2018/06/04 06:00 PHST- 2018/03/02 00:00 [received] PHST- 2018/05/18 00:00 [accepted] PHST- 2018/06/04 06:00 [pubmed] PHST- 2019/05/15 06:00 [medline] PHST- 2018/06/04 06:00 [entrez] PHST- 2018/05/31 00:00 [pmc-release] AID - 5025797 [pii] AID - jcem_201800500 [pii] AID - 10.1210/jc.2018-00500 [doi] PST - ppublish SO - J Clin Endocrinol Metab. 2018 Sep 1;103(9):3350-3358. doi: 10.1210/jc.2018-00500.