***TASK*** the task is to summarize an input biomedical literature in six sentences 
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    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    Input: In a double-blind prospect i ve clinical study patients with at least two verified episodes of urolithiasis , but stone-free at the time of inclusion in the study , were subjected to prophylactic treatment with either bendroflumethiazide ( 2.5 mg)+573 mg potassium chloride 3 times a day , or placebo . The material included a total of 22 patients , all males , aged 20–49 years . We found a clear tendency to reduced stone formation in the group treated with the active drug ( P<0.1 ) . Calcium excretion was reduced by 25–50 % in 7 of 12 patients treated with thiazide In an attempt to document the efficacy of potassium citrate in stone formation , 57 patients with active lithiasis ( 2 or more stones during the preceding 2 years ) and hypocitraturia were r and omly allocated into 2 groups , with 1 group taking 30 to 60 mEq . potassium citrate daily in wax matrix tablet formation and the other group receiving placebo . In 18 patients receiving  potassium citrate for 3 years stone formation significantly declined after treatment from 1.2 + /- 0.6 to 0.1 + /- 0.2 per patient year ( p < 0.0001 ) , in 13 patients ( 72 % ) the disease was in remission and all patients showed a reduced stone formation rate individually . In contrast , 20 patients taking placebo medication for 3 years showed no significant change in stone formation rate ( 1.1 + /- 0.4 to 1.1 + /- 0.3 per patient year ) and in only 4 patients ( 20 % ) was the disease in remission . The stone formation rate during potassium citrate treatment was significantly lower than during the placebo treatment ( 0.1 + /- 0.2 versus 1.1 + /- 0.3 per patient year , p < 0.001 ) . Potassium citrate therapy caused a significant increase in urinary citrate , pH and potassium , whereas placebo did not . Adverse reactions to potassium citrate were mild causing only 2 patients in the potassium citrate group and 1 in the placebo group to withdraw from the study . In summary , our r and omized trial showed the efficacy of potassium citrate in preventing new stone formation in idiopathic hypocitraturic calcium nephrolithiasis PURPOSE The intervention time of asymptomatic lower pole calculi remains controversial . In this prospect i ve study we evaluated the natural history and progression rate of asymptomatic lower pole stones . MATERIAL S AND METHODS Patients were followed every 6 months . Computerized tomography in even years , ultrasound scan in odd years after initial visit and abdominal plain films between these visits were evaluated . The largest diameter was measured for each calculus and the cumulative diameter was calculated for cases of multiple stones . Disease progression was defined as pain experienced during followup , stone growth or the need for intervention . RESULTS A total of 24 patients , 14 male and 10 female , were followed for a mean of 52.3 months ( range 24 to 72 ) . Of the 24 patients 3 had bilateral lower pole stones .  Mean cumulative stone diameter at presentation was 8.8 mm ( range 2.0 to 26.0 ) . Progression in stone size was demonstrated in 9 of 27 renal units ( 33.3 % ) with 2 ( 11.1 % ) requiring intervention . There was no need for intervention during the first 2 years of followup . Three stones passed spontaneously without any symptoms . Pain developed in 3 patients during followup , and 2 of them passed a stone and responded to the analgesics without further treatment . None of the patients had a pyelonephritic attack during followup . CONCLUSIONS Our results showed that observation could be considered for patients with asymptomatic lower pole stones . However , patients should be counseled about the 33 % disease progression and 11 % intervention rates OBJECTIVE To evaluate the preventive effects of alkaline citrate on stone recurrence as well as stone growth post-ESWL or PCNL in patients with calcium-containing stones . MATERIAL S AND METHODS A total of 76 patients with calcium calculi who were stone-free or had residual stones less than 4 mm following ESWL and PCNL were enrolled . All patients were independently r and omized into two groups . The treated group ( N = 39 ) was given 81 mEq per day of oral potassium-sodium citrate ( 27 mEq three times a day ) , and the untreated group ( N = 37 ) serving as controls . Blood , twenty-four hour urine analysis , and plain KUB were measured and compared at the baseline and after 12 months . RESULTS At baseline , hypocitraturia was found in 20 of 39 patients ( 46.05 % ) of Group I and 15 of 37 patients ( 40.5 % ) of Group II . At 12 months , hypocitraturia was found in 3 of 39 ( 7.69 % ) and 14 of 37 ( 37.83 % ) of Group I and Group II , respectively ( p = 0.007 ) . At the 12 month follow-up , of the stone-free group , 92.3 % of the treated group and 57.7 % of the control group were still stone free . Of the residual stone group , 30.8 % and 9.1 % of treated and control group were stone-free , respectively . The increased stone size found in 7.7 % ) and 54.5 % ) of treated and control groups , respectively . CONCLUSION Sodium-potassium citrate provides positive effects on stone-forming activities in calcium stone patients suffering from urolithiasis following treatment with ESWL and PCNL procedures at the 12-month follow-up BACKGROUND A high dietary calcium intake is strongly suspected of increasing the risk of kidney stones . However , a high intake of calcium can reduce the urinary excretion of oxalate , which is thought to lower the risk . The concept that a higher dietary calcium intake increases the risk of kidney stones therefore requires examination . METHODS We conducted a prospect i ve study of the relation between dietary calcium intake and the risk of symptomatic kidney stones in a cohort of 45,619 men , 40 to 75 years of age , who had no history of kidney stones .  Dietary calcium was measured by means of a semiquantitative food-frequency question naire in 1986 . During four years of follow-up , 505 cases of kidney stones were documented . RESULTS After adjustment for age , dietary calcium intake was inversely associated with the risk of kidney stones ; the relative risk of kidney stones for men in the highest as compared with the lowest quintile group for calcium intake was 0.56 ( 95 percent confidence interval , 0.43 to 0.73 ; P for trend , < 0.001 ) . This reduction in risk decreased only slightly ( relative risk , 0.66 ; 95 percent confidence interval , 0.49 to 0.90 ) after further adjustment for other potential risk factors , including alcohol consumption and dietary intake of animal protein , potassium , and fluid . Intake of animal protein was directly associated with the risk of stone formation ( relative risk for men with the highest intake as compared with those with the lowest , 1.33 ; 95 percent confidence interval , 1.00 to 1.77 ) ; potassium intake ( relative risk , 0.49 ; 95 percent confidence interval , 0.35 to 0.68 ) and fluid intake ( relative risk , 0.71 ; 95 percent confidence interval , 0.52 to 0.97 ) were inversely related to the risk of kidney stones . CONCLUSIONS A high dietary calcium intake decreases the risk of symptomatic kidney stones The study was performed to compare the efficacy of a herbal plant , Orthosiphon gr and iflorus ( OG ) , and the drug sodium potassium citrate ( SPC ) in treatment of renal calculi . Forty-eight rural stone formers identified by ultrasonography were recruited and r and omly assigned to two treatment groups ( G1 and G2 ) . For a period up to 18 months , subjects in G1 received 2 cups of OG tea daily , each tea cup made from an OG tea bag ( contained 2.5 g dry wt ) , and G2 received 5 - 10 g of granular SPC in solution divided into three times a day . Once every 5 to 7 weeks , subjects were interviewed , given an additional drug supply , administered a kidney ultrasound and had spot urine sample s collected for relevant biochemical analysis . From the recorded ultrasound images , rates of stone size reduction per year ( ROSRPY ) were calculated . The mean ROSRPY was 28.6+/-16.0 % and 33.8+/-23.6 % for G1 and G2 , respectively . These two means were not significantly different . ROSRPY values of G1 and G2 were combined and divided into three levels : Level A ( ROSRPY > mean + 0.5 SD ) , Level M ( ROSRPY = mean + /- 0.5 SD ) and Level B ( ROSRPY < mean - 0.5 SD ) . Dissolution of stones was least in Level B which was related to higher excretions of Ca and uric acid in the urine . After treatment , 90 % of the initial clinical symptoms ( ie back pain , headaches and joint pain ) were relieved . Fatigue and loss of appetite were observed in 26.3 % of G2 subjects . Our study indicates that treatment of renal calculi with OG tea is an alternative means of management . Further investigation is needed to improve dissolution of stones with a low ROSRPY OBJECTIVE To assess the efficacy of alkali citrate therapy in patients suffering from recurrent idiopathic calcium oxalate stone formation . PATIENTS AND METHODS Fifty patients suffering from active stone formation who had had at least one stone annually over the previous 3 years were recruited and r and omly divided into two groups . They were given either general prophylactic instructions , i.e. abundant liquid intake and dietary restrictions ( group I , n = 25)--or were additionally treated with alkali citrate ( group II , n = 25 ) . RESULTS In group I , the rate of stone formation was reduced from 1.8 to 0.7 stones per patient per year . Similar results were obtained for group II , the corresponding figures being 2.1 and 0.9 . There was a statistically significant higher urinary citrate excretion in group II than in group I. No difference was seen between the two groups regarding recurrent stone formation ( Student 's t-test ) . Stone formation decreased in both groups ( group I 27 % , group II 31 % ) . Subjectively , 56 % of group II patients , all of whom had previously experienced severe colic , reported spontaneous stone elimination to be painless , whereas in group I all but one patient suffered pain . CONCLUSION An objective benefit of alkali citrate could not be established We evaluated the possible effects of a calcium entry blocking agent “ verapamil ” on new stone formation and /or regrowth of residual fragments  after shock wave lithotripsy ( SWL )  during long-term follow-up ( > 30 months ) and compared the results with the success rates of adequate fluid intake . A total of 70 patients treated with SWL  were r and omly divided into three different groups , in the first two of which the patients received different preventive measures with respect to stone recurrence and /or regrowth . While 25 patients received a calcium channel blocking agent , verapamil hydrochloride , beginning 3 days before SWL and continued 4 weeks after the procedure , an additional 25 patients were put in an enforced fluid intake program and the remaining 20 patients received no specific medication and /or measure apart from close follow-up . Patients were followed regularly with respect to the clearance/regrowth of the residual fragments and that of new stone formation during long-term follow-up ( within a mean follow-up of 30.4 months ) . The overall stone recurrence rate was 14 % ( 10/70 ) . Of the patients who became stone free ( 12/25 , 48 % ) in group I , only one patient ( 1/12 , 8.3 % ) showed a new stone formation during long-term follow-up . The figure was 40 % ( 4/10 ) in group II patients and 55 % ( 5/9 ) in group III patients receiving no specific medication . Regarding the residual stone fragments ( < 5 mm ) after SWL , again high fluid intake was found to be the most effective on stone regrowth rates ( 2/13 , 15.3 % ) . Patients treated with verapamil also had acceptable regrowth rates ( 3/15 , 20 % ) . Finally , verapamil treatment significantly improved the clearance of residual fragments ; while 7 out of 15 patients with residual fragments passed these particles successfully , ( 46.5 % ) in this group ; these figures were 46 % ( 6/13 ) and 18 % ( 2/13 ) in the remaining groups . Residual fragments located in lower calyces demonstrated a poor clearance rate with higher regrowth rates .  Verapamil administration was found to be effective enough to limit the regrowth of residual fragments and also to facilitate residual fragment clearance after SWL . Patients receiving this medication seemed to pass the retained fragments easily in a shorter time than the others Low protein diets are commonly prescribed for patients with idiopathic calcium nephrolithiasis , who account for > 80 % of new diagnoses of kidney stones . This dietary advice is supported by metabolic studies and epidemiologic observational studies but has not been evaluated in a controlled trial . Using 1983 - 1985 data from three Northern California Kaiser Permanente Medical Centers , the authors r and omly assigned 99 persons who had calcium oxalate stones for the first time to a low animal protein , high fiber diet that contained approximately 56 - 64 
    Output:
    
In patients with multiple past calcium stones , most of whom were receiving increased fluid intake , moderate-strength evidence showed that thiazides ( RR , 0.52 [ CI , 0.39 to 0.69 ] ) , citrates ( RR , 0.25 [ CI , 0.14 to 0.44 ] ) , and allopurinol ( RR , 0.59 [ CI , 0.42 to 0.84 ] ) each further reduced composite stone recurrence risk compared with placebo or control , although the benefit from allopurinol seemed limited to patients with baseline hyperuricemia or hyperuricosuria .
Low-strength evidence showed that neither citrate nor allopurinol combined with thiazide was superior to thiazide alone .
There were few withdrawals among patients with increased fluid intake , many among those with other dietary interventions and more among those who received thiazide and citrate than among control patients .
CONCLUSION In patients with 1 past calcium stone , increased fluid intake reduced recurrence risk .
In patients with multiple past calcium stones , addition of thiazide , citrate , or allopurinol further reduced risk .