Objective To retrospectively analyze the clinical characteristics of 261 cases of hospitalized patients with type 1 diabetes mellitus (T1DM) in Peking Union Medical College Hospital (PUMCH).Methods Clinical data of 261 cases of hospitalized patients diagnosed with T1DM in the Department of Endocrinology at PUMCH from January 2007 to December 2014 were analyzed retrospectively. All patients were divided into the T1DM antibodies positive group (=180) and negative group (=81) according to the results of immunohistochemistry

in which 123 newly diagnosed T1DM patients were divided into the adult onset group (>18 years

=58) and non-adult onset group (≤18 years

=65) according to the onset age of T1DM

respectively. The clinical characteristics from different groups were compared.Results In 261 patients

the average age was 26.6±15.4 years

the average disease duration was 49 (1-480) months

the positive rate of antibodies to glutamic acid decarboxylase antibody was 58.8% (153/260). The level of 2-hour postprandial C peptide and the positive rate of T1DM antibodies in the non-adult onset group were higher than those in the adult onset group (0.98 0.52 ng/ml

=0.002 and 80.4% 62.5%

=0.048). The age of onset in the T1DM antibodies positive group was smaller than that in the T1DM antibodies negative group (19.7±11.4 24.7±15.6 years

=0.04)

while the incidence of ketosis in the T1DM antibodies positive group was higher than that in the T1DM antibodies negative group (48.3% 34.2%

=0.035). With the progress of the disease

the fasting C peptide level of the T1DM antibodies positive group decreased more rapidly. Compared with the single time hospitalized patients

multiple hospitalized patients had a lower incidence of diabetic retinopathy (8.2% 22.4%

=0.032)

a lower hemoglobin A1 level (8.04%±2.10% 9.56%±2.64%

<0.001) and fasting blood glucose level (8.7±3.1 10.9±4.2 mmol/L

<0.001).Conclusions Compared with the non-adult onset T1DM patients

the islet function of adult onset patients was even worse. In the T1DM antibodies positive patients

the islet β cell function decreased more rapidly

so the antibodies could not only clarify the diagnosis of T1DM and also predict prognosis of the islet β cell function. In the management of T1DM patients

regular hospital revisits contributed to get better glycemic control and reduced the occurrence of diabetic complications.