Current clinical state of type 1 diabetes in Saitama prefecture.

Introduction: In Japan, epidemiological studies on type 1 diabetes (T1D) have mainly focused on the disease in childhood. Meanwhile, limited information is available regarding the clinical features of adolescent and adult T1D. Therefore, we aimed to investigate their current clinical state in Saitama prefecture near Tokyo, Japan. Materials and methods: We conducted a cross-sectional, hospital-based, multicenter study. Eight institutions participated in the study, all of which treated relatively large numbers of T1D patients. We identified 1241 T1D patients aged 16 or over: 814 with acute-onset T1D (AT1D), 362 with slowly progressive insulin-dependent diabetes mellitus (SPIDDM), and 65 with fulminant T1D (FT1D). Based on the patient's medical records, various clinical parameters and complications were investigated. Results: Of 1241 patients, 739 (59.5%) were females. Among all patients, the median age, onset age, and disease duration were 51, 38, and 13 years, respectively. The patients had a median BMI of 22.6 kg/m2, and 26.1% were obese, corroborating previous nationwide surveys. Moreover, the median HbA1c was 7.8%, similar to previous nationwide surveys. Among patients with AT1D, SPIDDM, and FT1D, 85.6%, 72.1%, and 81.5% carried out multiple daily insulin injection, respectively, while 10.3%, 2.2%, and 18.5% were subject to continuous subcutaneous insulin infusion. The proportions of retinopathy, nephropathy, and neuropathy were 26.3%, 20.8%, and 21.5%. Conclusions: The glycemic control in T1D patients in Saitama was equivalent to that observed in previous nationwide surveys. Moreover, approximately one-quarter of T1D patients had obesity. Future studies should address whether our findings reflect those throughout Japan. Supplementary Information: The online version contains supplementary material available at 10.1007/s13340-021-00557-8.