and urinary metabolic defects were evaluated and predictors of primary hyperparathyroidism were evaluated using logistic regression with a priori adjustment for age, gender and body mass index (BMI). RESULTS: Stone forming patients with primary hyperparathy- roidism were more likely to be women (p0.001) and had higher levels of urinary calcium (difference 107 mg/day, p=0.006) but lower levels of urinary uric acid (difference 88 mg/day, p=0.045). Hypercalciuria was present in 64% of those with hyperparathyroidism and 38% of those without hyperparathyroidism (p=0.018). Calcium oxalate supersatura- tion (SSCaOx), calcium phosphate supersaturation (SSCaPhos), cal- cium/kilogram and calcium/creatinine were also elevated in primary hyperparathyroid patients. After adjusting for age and BMI, women were 4.9 fold (CI 1.8 –13.1) more likely to have hyperparathyroidism. Other predictors of hyperparathyroidism included hypercalciuria (aOR 3.5, CI 1.3–9.7), elevated SSCaOx (aOR 6.6, CI 2.7–15.9), elevated SSCaPhos (aOR 4.7, CI 1.8 –12.4), elevated calcium/kg (aOR 9.1, CI 3.7–22.4), and elevated calcium/creatinine (aOR 4.7, CI 1.5–14.5) in separate models after adjustment for age, gender and BMI. Other 24-hour urine parameters and metabolic defects were not associated with primary hyperparathyroidism. CONCLUSIONS: Stone forming patients with primary hyper- parathyroidism are more likely to be women and have elevated urinary calcium, SSCaOx and SSCaPhos after adjustment for age, gender and BMI. They also excrete more calcium/kg even after accounting for differences in patient size, but 36% of stone patients with primary hyperparathyroidism did not have hypercalciuria. There were no obvi- ous cutoffs for any urine parameters which reliably differentiated those with hyperparathyroidism among stone formers. Source of Funding: None 2223 URINARY ORNITHINE, ARGININE AND LYSINE MAY BE BETTER PREDICTORS OF CYSTINE STONE FORMATION AND PROGRESSION THAN URINARY CYSTINE Caroline Pardy*, Kathie Wong, Angela Doherty, Morloh Kabia, Matthew Bultitude, Giles Rottenberg, Vicky Moxham, Kay Thomas, London, United Kingdom INTRODUCTION AND OBJECTIVES: Cystinuria is the only clinically important manifestation of an inherited defect of the reabsorp- tion of dibasic amino acids; cystine, ornithine, arginine and lysine in the proximal tubule and small intestine. Patients form recurrent cystine stones often refractory to treatment. The aim of this study was to measure the predictive value of urinary cystine, ornithine, arginine and lysine in stone formation and progression in cystinuric patients. METHODS: A prospective dataset of 46 patients attending a specialist multi-disciplinary cystinuria clinic in our hospital between August 2008 and October 2010 was analysed. Stone formation was defined as radiological evidence of new stones, or increase in size of existing stones. Measurements of urinary cystine, ornithine, arginine and lysine were correlated with evidence of stone formation at the time of the urinary sample, 1 month and 6 months post sample. Subgroup analysis was performed for patients taking chelating agents (tiopronin or penicillamine). Mann Whitney test was used for statistical analysis. RESULTS: Median age 41yrs (17– 63). 132 urinary samples taken. Median number of samples per patient 3 (1– 6). 7 (15%) patients were taking chelating agents. There was no significant difference in urinary cystine levels between patients with/without new stone forma- tion at any of the time points; time of sample (p = 0.667), 1 month (p = 0.439) and 6 months (p = 0.980) post sample. There was no significant difference in urinary levels of ornithine, arginine and lysine in patients with/without new stone formation at the time of sample (p = 0.619, p = 0.493, p = 0.614 respectively). There was, however, a significant difference in urinary levels of ornithine, and arginine in patients with/ without new stone formation at 1 month (p = 0.001, p = 0.0001) and 6 months (p = 0.0015, p = 0.004) after the sample. Urinary lysine in patients with/without new stone formation approached but did not reach statistical significance at 1 month (p = 0.089) but was significant at 6 months (p = 0.049) after the sample. Subgroup analysis of the small number of patients on chelating agents revealed no significant differ- ence in urinary levels of any of the amino acids at any of the time points. CONCLUSIONS: This study demonstrates that in the monitor- ing of cystinuric patients, urinary ornithine, arginine and lysine may be of greater value than cystine. To our knowledge, this is the first study investigating the possibility of using the urinary levels of these amino acids rather than cystine to predict disease activity in patients with cystinuria. Source of Funding: None 2224 BISPHOSPHONATE PREVENTS THE RECURRENCE OF UROLITHIASIS IN POSTMENOPAUSAL WOMAN WITH OSTEOPOROSIS Takahiro Yasui*, Atsushi Okada, Kazumi Taguchi, Yasuhiko Hirose, Fujii Yasuhiro, Kazuhiro Niimi, Masayuki Usami, Ryosuke Ando, Shuzo Hamamoto, Takahiro Kobayashi, Masahito Hirose, Yasunori Itoh, Keiichi Tozawa, Kenjiro Kohri, Nagoya, Japan INTRODUCTION AND OBJECTIVES: Osteoporosis is charac- terized by a reduction in bone mineral density (BMD). Reduced BMD has been reported in urolithiasis patients with hypercalciuria, as well as in those with normocalciuria. Bisphosphonates potently inhibit bone resorption and are used in the management of osteoporosis. We investigated the ability of bisphosphonate to prevent the recurrence of urolithiasis. METHODS: We studied 24 postmenopausal women (64.3  8.2 years) diagnosed with osteoporosis, but without osteoporosis ther- apy, who had stones composed of calcium oxalate (CaOx) (n = 9), calcium phosphate (CaP) (n = 3), and CaOx+CaP (n = 12). We measured serum and urinary values in 24-hour urine specimens be- fore, 3 months, 12 months, and 24 months after the oral administration of 5 mg/day or 35 mg/week of alendronate (ALN), a new generation bisphosphonate compound. The indexes of the ionic activity product of CaOx, AP(CaOx), and of CaP, AP(CaP) were estimated using the Tiselius method. Sixteen of the 24 patients continued treatment for 2 years. We analyzed the preventive effect of ALN on the recurrence of urolithiasis by comparing the results to those of control osteoporosis subjects (n = 12, 65.0  8.2 years) who were treated for urolithiasis without ALN administration. RESULTS: ALN significantly reduced the excretion of urinary calcium (3.79  1.43 [before] to 3.22  1.27 [3 months], and 3.12  1.23 [12 months]; p  0.05) and the AP(CaP) index (1.55  1.17 [before], 0.89  0.79 [3 months], and 0.90  0.67 [12 months]; p  0.05). The urinary, oxalate, phosphate, and AP(CaOx) indexes showed no significant change. The incidence rate of urolithiasis (times/year) in patients treated with ALN was significantly lower than in those without ALN administration (0.083 and 0.208, respectively; p  0.05). CONCLUSIONS: Recent studies have indicated primary CaP plaque formation in the interstitial spaces of the renal papilla. ALN reduced the excretion of urinary calcium and the AP(CaP) index. The results suggest that ALN not only improves osteoporosis but also reduces the risk of calcium stone formation in postmenopausal women. Bisphosponate are believed to reduce the urinary excretion of calcium by improvement of bone metabolism, and to have a direct effect in the prevention of urolithiasis by preventing CaOx crystallization. e892 THE JOURNAL OF UROLOGY Vol. 185, No. 4S, Supplement, Wednesday, May 18, 2011