Effect of bone mineral density and parathyroidectomy on fracture risk in primary hyperparathyroidism

Bone mineral density is one parameter used to decide whether patients with primary hyperparathyroidism (PHPT) should undergo parathyroidectomy. However, the influence of bone mineral density and parathyroidectomy on subsequent fracture risk is unclear.

The authors conducted a retrospective cohort study of patients with PHPT based on administrative discharge abstract data. The dual energy x-ray absorptiometry (DEXA) scan T-scores at the femur were collected by chart review, and 10-year fracture-free survival (FFS) was the main outcome measured.

A total of 533 patients were identified, most of them > or = 50 years old (89%) and female (87%). Seventeen percent of the patients were black. Mean initial calcium, parathormone, and creatinine levels were 11.1 mg/dl, 116 pg/ml, and 0.9 mg/dl, respectively. Parathyroidectomy was performed in 159 (30%) patients, and 374 (70%) were observed. The 10-year FFS after PHPT diagnosis was 94% in patients treated with parathyroidectomy and 81% in those observed (p = 0.006). Compared to observation, parathyroidectomy improved the 10-year FFS by 9.1% (p = 0.99), 12% (p = 0.92), and 12% (p = 0.02) in patients with normal bones (T-score > or = -1.0), osteopenia (T-score < or = -1.0, > or = -2.5), and osteoporosis (T-score < -2.5), respectively. On multivariate analysis, parathyroidectomy was independently associated with decreased fracture risk (HR = 0.41; 95%CI 0.18, 0.93), whereas non-black race (HR = 2.94; 95%CI 1.04, 8.30) and T-score < -2.5 (HR = 2.29; 95%CI 1.08, 4.88) remained independently associated with increased fracture risk.

Parathyroidectomy decreases the risk of fracture in patients with normal, osteopenic, and osteoporotic bones. The largest impact from parathyroidectomy is in patients with osteoporosis. The highest risk of fracture is in non-blacks and in patients with osteoporosis.