After adjustment for age at diagnosis, duration of diabetes, BMI, GAD autoantibodies, eGFR, and HbA1c, three factors including duration of diabetes, GAD autoantibodies, and daily insulin dosage were still associated with lack of preserved C-peptide [OR 1.10 (IQR, 1.06–1.14); OR, 0.46 (IQR, 0.27–0.77); OR, 1.04 (IQR, 1.02–1.06)] Table 2. This evidence concerns the gene GAD1 and diabetes mellitus.