Epidemiologic studies have revealed a tremendous increase in the prevalence of diabetes and related mortality worldwide. In order to meet all the challenges in the treatment of metabolic diseases in China, the National Metabolic Management Center (MMC) was founded in 2016. The objective of the MMC is to launch a new metabolic disease management model based on the Internet health information platform. It allows the application and evaluation of diabetes treatment strategies at these centers. The proprietary electronic medical database in the MMC will help the dynamic big-data analysis in diabetes epidemiology, prevention, diagnosis, and treatment. It will also provide prospective data support including economic evaluation in management of chronic diseases for the Healthy China 2030 strategy. Objective 1. The purpose of the present study is to establish a multi-center nationwide prospective database of diabetes patients in MMCs, including clinical data, biological samples library so as to explore the epidemiology, genetics, new biomarkers, risk factors, and prognostic methods related to diabetes and its complications, as well as other metabolic diseases. 2. To collect cross-sectional data from patients seen and treated at each MMC centers so as to evaluate: the current status of care of patients with diabetes and its related complications, as well as other risk factors treatment strategies at these centers. Patients'costs and quality of life (QoL) will also be evaluated. 3. To collect the prospective data of patients treated at each MMC centers in order to evaluate the strategies for the achievement of treatment goals, changes in management, control of risk factors, incidence and progression of all-diabetes related clinical endpoints (including mortality), behavioral changes, psychological well being as well as costs and QoL.