 We will perform prevalence investigation, cross-sectional study, and prospective investigation for metabolic syndrome in our HD patients around 360 at present. We will enroll all the patients who receive maintenance HD more than three months in our HD center. The patients who are hospitalizing, suffered from active malignancy, active infections, recent cardiovascular events and surgery will be excluded in the beginning of study. Biochemistry and anthropometric parameters including HDL-C, TG, insulin resistance index, high sensitivity C-reactive protein and WC will be collected and analyzed. We will also prospectively establish the mortality and hospitalization indices of these patients, to study the prognosis of HD patient with or without metabolic syndrome. 