The impact of parathyroidectomy (PTX) on the bone mineral parameters in dialysis patients with secondary hyperparathyroidism (SHPT) remains unclear. The investigators performed this study to present the short- and long-term impact of PTX on calcium, phosphorus and intact parathyroid hormone control in dialysis patients with severe SHPT after operation. In particular, the investigators evaluate the impact based on the achievement of recommendations of the current clinical practice guidelines for bone and mineral parameters in dialysis patients after PTX.