Six-year follow-up of pancreatic beta cell function in adults with latent autoimmune diabetes.
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.
Yang
Lin
L
Institute of Metabolism and Endocrinology, the Second Xiangya Hospital, Central South University, Changsha 410011, Hunan Province, China.
Zhou
Zhi-Guang
ZG
Huang
Gan
G
Ouyang
Ling-Li
LL
Li
Xia
X
Yan
Xiang
X
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
D002096:C-Peptide