The effect of parathyroidectomy on bone fracture risk in patients with primary hyperparathyroidism

Background: Parathyroidectomy may increase bone density in primary hyperparathyroidism (PHPT), but it is unclear whether fracture risk is decreased. Hypothesis: Parathyroidectomy decreases fracture risk. Design: Retrospective cohort study with median follow-up of 6.5 years. Setting: Twelve regional hospitals in California. Patients: One thousand five hundred sixty-nine patients with PHPT. Interventions: Parathyroidectomy or observation. Main Outcome Measure: Fracture-free survival. Results: Mean initial calcium, parathyroid hormone, and creatinine levels were 11.2 mg/dL (2.8 mmol/L), 123.0 pg/mL, and 0.9 mg/dL (79.6 mu mol/L), respectively. Parathyroidectomy was performed in 452 (28.8%) patients, and 1117 (71.2%) were observed. The 10-year fracture-free survival after PHPT diagnosis was 73% in patients treated with parathyroidectomy compared with 59% in those observed (hazard ratio [HR], 0.53; 95% confideuce interval [CI], 0.38-0.73; P<.001). Parathyroidectomy decreased the 10-year hip fracture rate by 8% (P=.001) and the upper extremity fracture rate by 3% (P=.02). Parathyroidectomy was independently associated with a decreased fracture risk (HR, 0.68; 95% Cl, 0.47-0.98), whereas female sex (HR, 1.82; 95% Cl, 1.19-2.80) and increased creatinine level (HR per 1-mg/dL [88.4-mu mol/L increment, 2.05; 95% Cl, 1.22-3.46) remained independently associated with an increased fracture risk. Age of 50 years or older (HR, 1.62; 95% C1, 0.99-2.66), initial parathyroid hormone level (HR, 1.00; 95% Cl, 0.99-1.02), and calcium level (HR, 1.02; 95% Cl, 0.75-1.37) were not independently associated with fracture risk after adjusting for all other variables. Conclusions: Parathyroidectomy is associated with a decreased risk of fracture in PHPT. The largest decrease was in hip fractures. Parathyroidectomy should be considered for all patients with PHPT to reduce fracture risk, regardless of age or calcium or parathyroid hormone levels.