title: Six-year follow-up of pancreatic beta cell function in adults with latent autoimmune diabetes.
abstract: OBJECTIVE
  To investigate the characteristics of the progression of islet beta cell function in Chinese latent autoimmune diabetes in adult (LADA) patients with glutamic acid decarboxylase antibody (GAD-Ab) positivity, and to explore the prognostic factors for beta cell function.
  
  
  METHODS
  Forty-five LADA patients with GAD-Ab positivity screened from phenotypic type 2 diabetic (T2DM) patients and 45 T2DM patients without GAD-Ab matched as controls were followed-up every 6 mo. Sixteen patients in LADA1 and T2DM1 groups respectively have been followed-up for 6 years, while 29 patients in LADA2 and T2DM2 groups respectively for only 1.5 years. GAD-Ab was determined by radioligand assay, and C-peptides (CP) by radioimmune assay.
  
  
  RESULTS
  The percentage of patients whose fasting CP (FCP) decreased more than 50% compared with the baseline reached to 25.0% at 1.5(th) year in LADA1 group, and FCP level decreased (395.8+/-71.5 vs 572.8+/-72.3 pmol/L, P<0.05) at 2.5(th) year and continuously went down to the end of follow-up. No significant changes of the above parameters were found in T2DM1 group. The average decreased percentages of FCP per year in LADA and T2DM patients were 15.8% (4.0-91.0%) and 5.2% (-3.5 to 35.5%, P=0.000) respectively. The index of GAD-Ab was negatively correlated with the FCP in LADA patients (r(s)=-0.483, P=0.000). The decreased percentage of FCP per year in LADA patients were correlated with GAD-Ab index, body mass index (BMI) and age at onset (r(s)=0.408, -0.301 and -0.523 respectively, P<0.05). Moreover, GAD-Ab was the only risk factor for predicting beta cell failure in LADA patients (B=1.455, EXP (B)=4.283, P=0.023).
  
  
  CONCLUSIONS
  The decreasing rate of islet beta cell function in LADA, being highly heterogeneous, is three times that of T2DM patients. The titer of GAD-Ab is an important predictor for the progression of islet beta cell function, and age at onset and BMI could also act as the predictors.
authors.affiliation: Institute of Metabolism and Endocrinology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Zhi-Guang
authors.initials: ZG
authors.lastname: Zhou
authors.forename: Gan
authors.initials: G
authors.lastname: Huang
authors.forename: Ling-Li
authors.initials: LL
authors.lastname: Ouyang
authors.forename: Xia
authors.initials: X
authors.lastname: Li
authors.forename: Xiang
authors.initials: X
authors.lastname: Yan
mesh_terms: D000328:Adult; D001327:Autoimmune Diseases / Q000276:immunology* / Q000401:mortality / Q000503:physiopathology*; D002096:C-Peptide / Q000378:metabolism; D003924:Diabetes Mellitus, Type 2 / Q000276:immunology* / Q000401:mortality / Q000503:physiopathology*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007515:Islets of Langerhans / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012307:Risk Factors
chemical_list: D002096:C-Peptide