Overview

The aim of the China Diabetes Type 1 Study (CD1S) is to conduct a nationwide type 1 diabetes (T1D) registry study in patients with T1D and in pediatric adolescent patients with diabetes who had an age of onset \<= 20 years.

CD1S compromises a retrospective study enrolling inpatients hospitalized from Jan 1st, 2016 to Dec 31, 2021, and a prospective study beginning from the year 2022.

Eligibility

Inclusion Criteria:

• 1\. Patients with type 1 diabetes mellitus of any duration; meeting criteria (1) or any of (2) or any of (3)
  1. Clinical diagnosis of type 1 diabetes by a specialist
  2. Age at onset \< 15 years; no overweight or obesity at onset; previous diabetic ketoacidosis; highest random C-peptide \< 200 pmol/L
  3. Initiation and continuation of insulin therapy (except pancreatic or islet transplantation) after diagnosis; positive islet autoantibodies Or 2. Children and adolescents with diabetes mellitus at age of onset \<= 20 years, regardless of type and duration of disease.

Exclusion Criteria:

• For enrolment of patients with T1D, exclusion was made if any of the following criteria were met (not applicable to those with onset under 20 years of age)
  • No insulin dependence for at least 6 months after diagnosis of diabetes mellitus.
    • No DKA for 1 month off insulin for those with a history of diabetes \> 1 year. ③ C-peptide \> 800 pmol/L at any time point.