Incidence of hypercalcemia, hypercalciuria and related factors in patients treated with recombinant human parathyroid hormone (1-84).

Aim: The aim of this paper was to determine the incidence of hypercalcemia and hypercalciuria (and related factors) in 22 postmenopausal women with osteoporosis treated with PTH (1-84) in daily practice.

Methods: Osteoporosis was defined as history of osteoporotic fracture or a T score less than -3 SD on bone densitometry. Patients were treated with PTH (1-84), 100 mcg/daily, for 12 months. Clinical and laboratory data at baseline and after 6 months of treatment were assessed.

Results: The mean age was 71.9 years. The incidence of hypercalcemia and the hypercalciuria were 6 events. Increase in serum calcium levels showed a statistically significant correlation with 24-hour urinary calcium (rho [ρ]=0.83, P<0.001), serum alkaline phosphatase (ρ=0.76, P=0.001), total proteins (ρ=0.77, P=0.005), and β-CTx (ρ=0.82, P=0.002). On the other hand, 24-hour urinary calcium excretion correlated significantly with β-CTx (ρ=0.83, P=0.002), alkaline phosphatase (ρ=0.73, P=0.005), total proteins (ρ=0.73, P=0.02), and serum phosphate (ρ=0.58, P=0.04). When the group of patients with and without hypercalcemia were compared, there were statistically significant differences in increases of β-CTx and baseline β-CTx values, whereas the group of patients with and without hypercalciuria showed significant differences in serum calcium increases and baseline values of T score at the femoral neck.

Conclusion: The incidence of hypercalcemia and hypercalciuria after treatment with PTH (1-84) is similar to that expected according to the product's technical specifications. There was a significant correlation between increases of serum calcium, urinary calcium excretion, serum alkaline phosphatase, and β-CTx after treatment with PTH (1-84). Baseline β-CTx values were significantly lower in patients who developed hypercalcemia than in those with normal serum calcium levels.