Objective To explore the clinical characteristics and influencing factors of positive insulin autoantibody (IAA) in patients with type 2 diabetes mellitus (T2DM).

Methods The serum IAA was detected in 163 T2DM patients, and the patients were divided into IAA positive group(n=97) and IAA negative group(n=66). The general data, biochemical indexes and result of insulin release test were compared between the two groups, and the influencing factors of positive IAA were analyzed.

Results The age of patients in the IAA positive group was older than that in the IAA negative group, the course of disease was longer than that in the IAA negative group, and the level of free triiodothyronine (FT₃) was lower than that in the IAA negative group(P < 0.05). The proportion of patients using premixed insulin analogue in the IAA positive group was higher than that in the IAA negative group (P < 0.05). Age, duration of diabetes, FT₃ level, use of premix insulin analogue and insulin levels at 0 and 180 min in insulin release test were independent risk factors of positive IAA in T2DM patients(P < 0.05).

Conclusion Increasing age, prolongation of disease duration and use of premixed insulin analogues may increase the risk of positive IAA in T2DM patients. The decrease of FT₃ level and the significant increase of fasting insulin and postprandial insulin levels should also be noted for the occurrence ofpositive IAA.