The Relationship of Parathyroidectomy and Bisphosphonates With Fracture Risk in Primary Hyperparathyroidism: An Observational Study

Abstract

Background: The comparative effectiveness of surgical and medical treatments on fracture risk in primary hyperparathyroidism (PHPT) is unknown.

Objective: To measure the relationship of parathyroidectomy and bisphosphonates with skeletal outcomes in patients with PHPT.

Design: Retrospective cohort study.

Setting: An integrated health care delivery system.

Participants: All enrollees with biochemically confirmed PHPT from 1995 to 2010.

Measurements: Bone mineral density (BMD) changes and fracture rate.

Results: In 2013 patients with serial bone density examinations, total hip BMD increased transiently in women with parathyroidectomy (4.2% at <2 years) and bisphosphonates (3.6% at <2 years) and declined progressively in both women and men without these treatments (-6.6% and -7.6%, respectively, at >8 years). In 6272 patients followed for fracture, the absolute risk for hip fracture at 10 years was 20.4 events per 1000 patients who had parathyroidectomy and 85.5 events per 1000 patients treated with bisphosphonates compared with 55.9 events per 1000 patients without these treatments. The risk for any fracture at 10 years was 156.8 events per 1000 patients who had parathyroidectomy and 302.5 events per 1000 patients treated with bisphosphonates compared with 206.1 events per 1000 patients without these treatments. In analyses stratified by baseline BMD status, parathyroidectomy was associated with reduced fracture risk in both osteopenic and osteoporotic patients, whereas bisphosphonates were associated with increased fracture risk in these patients. Parathyroidectomy was associated with fracture risk reduction in patients regardless of whether they satisfied criteria from consensus guidelines for surgery.

Limitation: Retrospective study design and nonrandom treatment assignment.

Conclusion: Parathyroidectomy was associated with reduced fracture risk, and bisphosphonate treatment was not superior to observation.

Primary funding source: National Institute on Aging.