Tapering decay of β-cell function in Chinese patients with autoimmune type 1 diabetes: A four-year prospective study

This study investigated the natural progression of β-cell function in Chinese autoimmune type 1 diabetic (T1D) patients and clarified factors possibly influencing the course of the disease.

The natural progression of β-cell function of 325 newly diagnosed Chinese autoimmune T1D patients was assessed by fasting and postprandial C-peptide (FCP and PCP, respectively) levels. β-Cell function failure was defined as FCP <50 pM and PCP <100 pM, whereas preserved β-cell function was defined as FCP >200 pM or PCP >400 pM. β-Cell function that did not meet these criteria was described as residual.

At initial recruitment, 33.3% of patients had β-cell function failure, whereas 41.0% and 25.8% of patients had preserved or residual β-cell function, respectively. The percentage of patients who developed β-cell function failure during follow-up at 12, 24, 36, and 48 months after recruitment to the study was 55.8%, 75.6%, 86.7%, and 92.7%, respectively. Moreover, the slope of the β-cell function curve decreased over time, indicating that the pattern of its decline was non-linear and tapering. Seven percent of patients did not develop β-cell function failure within 4 years after diagnosis. Patients with lower initial FCP levels were more likely to develop β-cell function failure.

Chinese autoimmune T1D patients have considerable residual β-cell function at initial diagnosis, and the manner of progression of β-cell function failure is non-linear with a tapering decay rate. Furthermore, initial FCP levels may predict β-cell function failure in Chinese autoimmune T1D patients.