Does Hypoparathyroidism Protect Against Fractures?
2Statistical Consulting Unit, Rabin Medical Center, Beilinson Hospital
3Sackler Faculty of Medicine, Tel Aviv University
4Department of Endocrinology and Diabetes, Clalit Health Services
Introduction:
Patients with Hypoparathyroidism (HypoPT) have low bone turnover and high bone mineral density (BMD) due to the lack of PTH-mediated bone resorption. Yet, data on fracture risk is controversial.
Aims:
1. To assess fracture rate in patients with hypoPT of different etiologies. 2. To compare fracture incidence between gender and age-matched groups of post-thyroidectomy patients with/without hypoPT.
Methods:
Retrospective analysis, based on a computerized database of patients treated between 2010-2021 at a tertiary medical-center.
Results:
The study included 137 patients (91% women, age 64±13), of whom 105 (79%) had post-thyroidectomy hypoPT, and 21% had autoimmune/idiopathic etiology. Mean follow-up was 21±12 and 27 ±12 years, respectively, p=0.09. Patients with postsurgical HypoPT had significantly higher fracture risk than the non-surgical hypoPT patients (HR 9.04, 94% CI (1.31-62.19. (
Comparison of 105 patients with post-surgical hypoPT to 142 post-thyroidectomy patients without hypoPT revealed a higher BMD in HypoPT patients. Yet, the prevalence of fractures was 31% (32/105) in the hypoPT patients and 21% (30/142) in patients without hypoPTH (p=0.1) during a similar follow-up period (median 17 and 18.4 years, respectively). In both groups, the most common fracture site was the spine (50 % and 70% in HypoPT and control group, p=0.33). Most vertebral fractures were non-clinical morphometric.
Conclusion:
The relatively high BMD in patients with hypoPT is not associated with a lower fracture risk. As clinically-undiagnosed vertebral fractures are common, spinal imaging should be routinely performed, and treatment with PTH- replacement therapy should be considered in patients with increased fracture risk.
