Multiple factors affect the loss of measurable C-peptide over 6 years in newly diagnosed 15- to 35-year-old diabetic subjects

• Published in: Journal of diabetes and its complications Vol. 21; no. 4; pp. 205 - 213
• Main Authors: Jensen, Richard A, Gilliam, Lisa K, Törn, Carina, Landin-Olsson, Mona, Karlsson, F. Anders, Palmer, Jerry P, Kockum, Ingrid, Åkesson, Karin, Lernmark, Barbro, Lynch, Kristian, Breslow, Norman, Lernmark, Åke
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-07-2007; Elsevier Limited
• Subjects: Adolescent; Adult; Autoantibodies; Autoantibodies - immunology; C-peptide; C-Peptide - blood; C-Peptide - immunology; Clinical Medicine; Diabetes; Diabetes Mellitus - blood; Diabetes Mellitus - diagnosis; Diabetes Mellitus - epidemiology; Diabetes Mellitus - immunology; Endocrinology & Metabolism; Endocrinology and Diabetes; Endokrinologi och diabetes; Female; Follow-Up Studies; Genotype & phenotype; Haplotypes; Humans; Insulin resistance; Klinisk medicin; Male; Medical and Health Sciences; MEDICIN; Medicin och hälsovetenskap; MEDICINE; Risk Factors; Time Factors; Type 1 diabetes mellitus; Type 2 diabetes mellitus; Autoantibodies; Type 2 diabetes mellitus; C-peptide; Type 1 diabetes mellitus
• ISSN: 1056-8727; 1873-460X; 1873-460X
• DOI: 10.1016/j.jdiacomp.2006.01.004

Abstract Objective The aim of this study is to identify risk factors for the loss of measurable plasma C-peptide in newly diagnosed 15- to 35-year-old diabetic subjects. Methods This Swedish study included 778 subjects. C-peptide levels were obtained each year for 6 years after diagnosis. Loss of measurable C-peptide was defined as a level at or below the lower detection limit of the local assay (0.13 nmol/l). In addition to C-peptide, other baseline covariates included gender, age, body mass index, HLA genotype, and autoantibody levels. Results Compared with autoantibody-negative subjects, autoantibody-positive subjects had lower median baseline C-peptide (0.27 vs. 0.50, P <.001), their levels declined over the study period, and the risk of losing measurable C-peptide was significantly higher when more than one autoantibody was present [odds ratio (OR), 4.0; 95% confidence interval (CI), 2.13–7.54]. Among autoantibody-positive individuals, the presence of GAD65Ab (OR, 1.8; 95% CI, 1.24–2.51) and islet cell antibodies (OR, 1.6; 95% CI, 1.19–2.18) conferred a higher risk for loss of measurable C-peptide as did female gender (OR, 1.6; 95% CI, 1.17–2.11) and time after diagnosis (OR, 1.5 for each additional year postdiagnosis; 95% CI, 1.41–1.57). Higher baseline C-peptide levels were protective (OR, 0.5 for each additional log e nanomoles per liter; 95% CI, 0.36–0.58). Conclusions This study identified autoantibody status, gender, and baseline C-peptide levels as factors that will be useful for predicting the disease course of 15- to 35-year-old diabetic individuals.