STUDY AIMS: To survey bone mineral disturbances in the hemodialysis (HD) population in Europe and current clinical practice in Europe for the prevention, diagnosis and treatment of secondary hyperparathyroidism (SHPT) in HD patients. PRIMARY OBJECTIVES: First, to estimate the prevalence of Kidney Disease Outcomes Quality Initiative (K/DOQI) guideline achievement in a representative sample of European hemodialysis subjects. As part of this objective, we will investigate the prevalence of achievement by type of dialysis, type of center and time on dialysis (less than or greater than 1 year). Among new dialysis subjects (less than 1 year), we will evaluate prevalence of K/DOQI target achievement until the end of the study. The study will run for 3 years. Second, to estimate the association of bone mineral markers (parathyroid hormone [PTH], calcium [Ca], serum phosphorus [P] and calcium phosphate product [CaxP]) classified by achievement of K/DOQI targets with mortality and overall cardiovascular hospitalization. Third, to characterize the longitudinal changes in bone mineral markers. As part of this objective, we will describe the patterns and predictors of bone mineral markers and achievement, with K/DOQI targets, using repeated measurements on individuals over time. SECONDARY OBJECTIVES: First, To estimate the association of bone mineral markers (PTH, Ca, P and CaxP) classified by achievement of K/DOQI targets with specific cardiovascular outcomes, parathyroidectomy, manifest bone disease (including incidence of symptomatic bone fractures), hospitalizations and vascular access. Second, to evaluate the additional value of albumin and hemoglobin levels in conjunction with bone mineral markers in the prediction of mortality and clinical events.