Multicenter Registry Study of Chronic Hypoparathyroidism in Chinese Adults

This study consists of four parts, the eligibility criteria of each part is described below: Part 1: Search criteria of chronic HP: Inclusion Criteria: * Existing diagnosis of HP Exclusion Criteria: * Age\<18 at the time of screening Search criteria of suspected HP: Inclusion Criteria: * Hypocalcemia plus neck surgery * Hypocalcemia plus convulsions/tetany/epilepsy * Hypocalcemia plus PTH\<upper limit, and no hypoalbuminemia * Hypocalcemia without any of the following conditions: neck surgery, convulsions/tetany/epilepsy, PTH testing, hypoalbuminemia, critical illness and vitamin D deficiency-related diseases. Exclusion Criteria: * Age\<18 at the time of screening Diagnosis of chronic HP: Inclusion Criteria: * Hypocalcemia (albumin adjusted total calcium \< lower limit) with inappropriate reduction of serum PTH level (PTH \< upper limit). * The course of hypoparathyroidism should be more than 6 months. Part 2 Inclusion Criteria: * Patients with chronic HP confirmed through medical records review * Patients with suspected HP confirmed through medical records review * Obtain written informed consent Exclusion Criteria: * Non-local residents Part 3 Inclusion Criteria: * Patients with chronic HP * Participating in the on-site survey in the Peking Union Medical College Hospital Part 4 Inclusion criteria: * Endocrinologists involved in HP care from 7 sites * Obtain written informed consent