Background: Non-surgical hypoparathyroidism (NS-HypoPT) is a rare disease, characterised by low levels of calcium and PTH. A number of genetic variants have been shown to cause inadequate PTH secretion, although the aetiology often remains unknown. It may also appear on autoimmune basic, either isolated, as a part of the autoimmune polyendocrine syndrome, associated with APS-1, or as acquired antibodies that activate the calcium sensing receptor (CaSR). Autosomal dominant hypocalcaemia (ADH) is caused by an activating mutation (gain-of-function) in the CaSR. Little is known about this group of patients, including their mortality and morbidity. The aim was to identify all patients diagnosed with NS-HypoPT in Denmark and assess their mortality and risk of complications.
Methods: Cases (patients with NS-HypoPT) were identified through registers and review of their individual hospital charts. To access their mortality and morbidity we compared the cases with a group of age-and gender matched population based controls.
Results: In a population of 5.336.394 persons, a total of 180 cases with NS-HypoPT were identified, among whom 123 (68%) were alive at the day of follow-up, equal to a prevalence of 2.3/100,000 inhabitants). Only 38 were genetic verified. Compared with controls, mortality was not increased, but patients had a significantly increased risk of seizures (Hazard ratio [HR] 10.05) renal insufficiency (HR 6.01), cataract (HR 4.21), neuropsychiatric complications (HR 2.45), infections (HR 1.94), cardiovascular diseases (HR 1.91) and fractures at the upper extremities (HR 1.93). In contrast, patients had significantly reduced risk of malignant diseases (HR 0.44).
Conclusion: NS-HypoPT is a rare disease associated with a number of complications that should be considered when taking care of these patients.
Disclosure: The authors declared no competing interests.