CLINICAL STUDIES OF CITRATE THERAPY ON UROLITHIASIS : Estimations of Urinary Citrate Excretion in Patients with Urolithiasis and the Results of Treatment with Sodium-Potassium Citrate

1. Calcium stone formers (male;170, female;61) and healthy controls (male;72, female;37) were examined with respect to urinay citrate and several urinary biochemistries. Urinary citrate was determined using an enzymatic method which we had reported. The following results were obtained: 1) The mean value of urinary citrate excretion was 383.9±156.5 mg/day in male controls, and 452.6±171.4 mg/day in female controls. In healthy controls, urinary citrate in females was significantly higher than in males (p<0.05). 2) In male patients with calcium urolithiasis urinary citrate was significantly lower than the healthy controls. In female patients urinary citrate excretion was significantly lower only in the group of recurrent stone formers. 3) Hypocitraturia was defined when citrate excretion was under 200 mg/day in males and under 250 mg/day in female. According to this definition, 45 of 116 male patients (26.5%) and 17 of 61 female patients (27.9%) were classified to hypocitraturia. 4) Hypocitraturia was associated with hypercalciuria in 12.4 per cent of male stone formers, and in 6.6 per cent of female stone formers. Both of hypocitraturia and hyperoxaluria were found in only about 10 per cent of stone formers in both sexes. These results showed that hypocitraturia itself was one of the serious risk factors of stone formation. 5) There were low statistical correlation between urinary citrate and urine volume, urinary magnesium, uric acid, phosphorus or oxalate. Urinary citrate was correlated with urinary calcium only in stone formers and was not correlated with urinary pH. 2. Citrate therapy with sodium-potassium-citrate (CG-120) was performed in 31 calcium stone formers. During the therapy urinary citrate excretion was significantly increased and the effect was sustained. Of 23 patients, who have received citrate therapy for at least 6 months, only two patients had recurrence of stones after treatment. Citrate therapy was considered to be useful for preventing the recurrence of calcium urolithiasis.