The goal of this observational study or clinical trial is to learn about the effect of neutrophil gelatinase-associated lipocalin (NGAL) on vascular calcification in maintenance hemodialysis patients with secondary hyperparathyroidism (SHPT). The main question it aims to answer is: the predictive effects of blood NGAL level on the efficacy of palicalcitol in the treatment of SHPT and the adverse reactions of vascular calcification progression. Participants will be treated with palicalcitol, followed up and undergo routine series of Chronic Kidney Disease-Mineral and Bone Disorder associated tests before and after treatment.