Primary hyperparathyroidism (PHPT) may favor nephrolithiasis mainly through an increase in calcium and phosphate urinary excretion. Cinacalcet exhibits good efficacy to control hypercalcemia in PHPT, but it is not so far known whether it might be a useful tool to prevent stone recurrences.
Of 67 patients with PHPT and recurrent nephrolithiasis, 55 underwent parathyroidectomy (PTX) and 12, not eligible to PTX, were prescribed Cinacalcet. All the patients were evaluated for mineral metabolism, including estimation of state of saturation for calcium oxalate (ßCaOx) and brushite (ßbsh), both at baseline and after either PTX or Cinacalcet.
PTX compared to baseline reduced PTH (46±17 vs 157±86 pg/mL, p<0.01), calcemia (9.4±0.5 vs 11.3±0.9 mg/dL, p<0.01), calciuria (3.6±2.3 vs 9.2±4.5 mmol/24h, p<0.01), phosphaturia (18.4±7.1 vs 21.9±9.9 mmol/24h, p<0.05), ßCaOx (4.7±3.9 vs 9.8±6.8, p<0.01) and ßbsh (1.1±0.9 vs 3.2±2.2, p<0.01). Cinacalcet decreased both PTH (133±79 vs 171±87 pg/mL, p<0.05) and calcemia (9.7±0.6 vs 11.2±0.8 mg/dL, p<0.001), whereas no change was seen in calciuria (7.4±2.2 vs 7.4±2.4 mmol/24h, p=ns), phosphaturia (21.9±7.3 vs 23.0±6.5 mmol/24h, p=ns), ßCaOx (6.9±2.7 vs 5.4±2.5, p=ns) and ßbsh (1.7±1.1 vs 1.3±1.3, p=ns).
We conclude that in patients with PHPT, PTX is able to decrease the risk for crystallization of calcium salts, whereas calcimimetic Cinacalcet did not.
Therefore, in patients with PHPT complicated with nephrolithiasis only PTX can improve urine biochemistries thereby reducing the risk for recurrent calcium stone disease.
Full text of the article is available in Italian.