Long-term potassium citrate therapy and bone mineral density in idiopathic calcium stone formers.

Several authors have described an association between idiopathic calcium (Ca) stone disease and bone mass reduction. Hypocitraturia is a frequent feature of urolithiasis, and alkaline citrate has been recommended as one of the choice treatments in this disease. Some evidence exists as to the positive effect of potassium (K) citrate therapy on bone mass. The aim of this work was the longitudinal evaluation of bone mineral density (BMD) changes in a group of Ca oxalate stone formers treated with K citrate for two years. Enrolled patients were 120; 109 subjects completed the study (51 males and 58 females). A metabolic study and distal radius BMD measurements were conducted both at baseline (BAS) and at the end of the study (END). BMD (0.451 +/- 0.081 vs 0.490 +/- 0.080 g/cm2), T-score (-1.43 +/- 1.02 vs -0.90 +/- 1.04), net gastrointestinal alkali absorption (40.37 +/- 50.57 vs 61.26 +/- 42.26 mEq/day), urinary citrate (2.53 +/- 1.15 vs 3.10 +/- 1.44 mmol/day) and K (58.93 +/- 22.28 vs 65.45 +/- 23.97 mmol/day) excretion significantly increased from BAS to END. Urinary Ca excretion remained unchanged from BAS to END (5.16 +/- 2.74 vs 5.57 +/- 2.85 mmol/ day). Our results indicate that long-term treatment with K citrate increases forearm BMD in idiopathic Ca stone formers. It seems probable that the alkali load provided by this drug reduces bone resorption by a buffering of the endogenous acid production. K citrate appears to be a further therapeutic opportunity for the management of osteoporosis in Ca stone formers.

Comparative study of the influence of 3 types of mineral water in patients with idiopathic calcium lithiasis.

PURPOSE: While there is general agreement on the need to increase urinary volume in stone formers, contrasting opinions have been expressed about the hardness of water and stone incidence. We evaluate the influence of 3 types of mineral water on urinary analytes in 22 idiopathic calcium oxalate stone formers. MATERIALS AND METHODS: All patients underwent a nutritional and metabolic evaluation at baseline, and after a controlled diet including water with a high, medium or low calcium content. RESULTS: In patients who drank water with high and medium calcium contents calcium excretion increased, although the results did not reach statistical significance. In those who drank water with the highest calcium content oxalate excretion significantly decreased (p = 0.05), as did the oxalate-to-calcium ratio (p = 0.05). Moreover, these modifications did not induce relevant changes in urinary saturation. In patients who drank water with the greatest amount of bicarbonate citrate excretion increased (p = 0.03). CONCLUSIONS: Mineral water with a higher calcium content induced increased calcium excretion but significantly decreased oxalate excretion. These data are in accordance with those of others, who did not find definite evidence that hard water is more lithogenic than soft water. Furthermore, water components other than calcium can modify the tendency toward crystal formation, affecting inhibitory power and/or lithogenic salt excretion.