A Population-based study of the Epidemiology of Chronic Hypoparathyroidism

There are very few reports on the epidemiology of chronic hypoparathyroidism. A population-based study was undertaken to describe the prevalence and incidence of hypoparathyroidism in Tayside, Scotland. Data on biochemistry, hospital admissions, prescribing and death records in Tayside Scotland from 1988 to 2015 were linked electronically. Patients with at least three serum albumin corrected calcium concentrations below the reference range that were taken in an out-patient setting were included in the study. Patients with severe chronic kidney disease prior to low calcium were excluded from the study. Patients with hypocalcaemia were included if they had either previous neck surgery/irradiation, a low serum PTH or were treated with Vitamin D. Patients were identified as having either a post-surgical, a non-surgical cause, or had secondary hypoparathyroidism e.g. hypomagnesaemia. Overall 18,955 patients were identified with hypocalcaemia. Of these 222 patients had primary hypoparathyroidism, 116 with post-surgical and 106 with non-surgical chronic hypoparathyroidism. In 2015 the prevalence of primary hypoparathyroidism was 40 per 100,000, with a rate of 23 and 17 per 100,000 respectively for post-surgical and non-surgical. 80% of the former and 64% of the latter were female. The mean serum calcium at diagnosis was 1.82mmol/l (SD ± 0.24) and the annual incidence varied from 1-4 per 100,000. Overall, 71% of patients were prescribed Vitamin D and/or calcium, whilst activated Vitamin D was used in 48% of post-surgical cases and 43% of non-surgical cases. Thyroxine and/or hydrocortisone were prescribed in over 90% of post-surgical and 64% of non-surgical cases. In conclusion, the prevalence of non-surgical chronic hypoparathyroidism was greater than previously reported using this population-based approach. Many had mild hypocalcaemia and did not receive any treatment. This article is protected by copyright. All rights reserved.