urinary stone disease affects 5 to 10% of the world 's population , and it is one of the most common reasons for patients to visit a urologic clinic . furthermore , several studies have shown a worldwide trend toward an increasing prevalence of stone disease ; a trend that is also observed in korea . the goal of treating ureter stones is to achieve complete stone clearance with minimal patient morbidity . the standard treatment of ureter stones today is observation , medical therapy , shockwave lithotripsy ( swl ) , and ureteroscopic ureterolithotomy . medical expulsive therapy ( met ) for ureter stones has especially gained increasing attention in the past decade , and there is growing evidence that met can be efficacious to facilitate stone passage . various medications , such as calcium channel blockers ( nifedipine and verapamil ) , -blockers ( tamsulosin , alfuzosin , doxazosin , and terazosin ) , and corticosteroids have been investigated . among these drugs , tamsulosin seems to be the most effective in facilitating stone clearance , both in patients undergoing expectant management and in those undergoing swl . several reports based on meta - analyses of randomized controlled trials ( rcts ) support this fact [ 4 - 7 ] . although there are several rcts on this subject , the majority of them were small , single - center studies [ 8 - 12 ] . thus , even if the study showed a trend favoring tamsulosin , the results would be statistically insignificant or partly significant by subgroup analysis . there is currently no conclusive evidence that tamsulosin augments stone clearance in the korean population . the aim of this study was to conduct a meta - analysis of evidence from rcts to assess the efficacy of tamsulosin in the treatment of ureter stones with or without swl in korean patients . such evidence can aid physicians in making decisions in their clinical practice for the korean population . medline , koreamed , and the korean medical database were searched through june 30 , 2011 , without a time limit . all rcts were identified in which patients were randomly selected to receive either tamsulosin or standard therapy with or without placebo to treat ureter stones . the search was conducted by exploring and combining the following medical terms : ( urolithiasis or urinary calculi or ureterolithiasis or stone ) and ( alpha - antagonists or tamsulosin ) . two reviewers independently extracted data from each study by using a standardized form . the quality of the included randomized studies was assessed by using the jadad scale score reporting for each study , which ranged from 0 to 5 points . the jadad score is assigned according to randomization and the quality of randomization , blinding , quality of allocation concealment , and description of dropouts . meta - analyses were performed mainly by using the package meta . for all statistical comparisons , differences with a p<0.05 were considered significant . the mantel - haenszel test pooled risk ratios ( rrs ) and 95% confidence intervals ( cis ) were calculated for the effects of tamsulosin . the chi - squared (  ) test when heterogeneity was present ( p<0.1 ) , the data were analyzed by using the random effects model . in the absence of heterogeneity , a fixed effects model was applied . the risk differences ( rds ) for stone clearance were plotted against the standard error ( se ) of the rd . forest plots were applied by visualizing the rr in each square with the area proportional to the number of events ; 95% cis were visible as horizontal lines . subgroup meta - analyses were performed by stone location ( upper or lower ureter stone ) and whether swl was applied or not . medline , koreamed , and the korean medical database were searched through june 30 , 2011 , without a time limit . all rcts were identified in which patients were randomly selected to receive either tamsulosin or standard therapy with or without placebo to treat ureter stones . the search was conducted by exploring and combining the following medical terms : ( urolithiasis or urinary calculi or ureterolithiasis or stone ) and ( alpha - antagonists or tamsulosin ) . two reviewers independently extracted data from each study by using a standardized form . the quality of the included randomized studies was assessed by using the jadad scale score reporting for each study , which ranged from 0 to 5 points . the jadad score is assigned according to randomization and the quality of randomization , blinding , quality of allocation concealment , and description of dropouts . meta - analyses were performed mainly by using the package meta . for all statistical comparisons , differences with a p<0.05 the mantel - haenszel test pooled risk ratios ( rrs ) and 95% confidence intervals ( cis ) were calculated for the effects of tamsulosin . the chi - squared (  ) test when heterogeneity was present ( p<0.1 ) , the data were analyzed by using the random effects model . in the absence of heterogeneity , a fixed effects model was applied . the risk differences ( rds ) for stone clearance were plotted against the standard error ( se ) of the rd . forest plots were applied by visualizing the rr in each square with the area proportional to the number of events ; 95% cis were visible as horizontal lines . pooled rrs and corresponding 95% cis subgroup meta - analyses were performed by stone location ( upper or lower ureter stone ) and whether swl was applied or not . 10 studies were conducted with korean patients . finally , a total of 6 articles were identified by our search strategy that met the eligible criteria ( fig . two studies were for expectant treatment , three studies were for concomitant use with swl , and one multicenter study was for both situations . the characteristics and the jadad scale scores of the 6 included studies are summarized in table 1 . 3 shows that tamsulosin had an overall benefit for ureteral stone clearance over the control ( rr , 1.43 ; 95% ci , 1.24 to 1.65 ) . subgroup analyses also demonstrated this significant effect in all situations ( figs . 4 , 5 ) . tamsulosin treatment for lower ureter stones ( rr , 1.50 ; 95% ci , 1.20 to 1.88 ) showed a relatively higher rr than for upper ureter stones ( rr , 1.31 ; 95% ci , 1.02 to 1.68 ) . the adrenoceptors of these subtypes exist in the smooth muscle cells of the human ureter . 1-blockers decrease tension , release the spasm of smooth muscles , lessen obstructions , and , consequently , enhance stone elimination in the ureter . the distal ureter has the highest density of adrenoceptors , and the 1d - receptor is the most common receptor present in all portions of the ureter . thus , tamsulosin , which is more selective for the 1d - subtype , can be considered the most effective drug for met among the -blockers . distal ureter stones in particular may be more affected by tamsulosin , because the highest density of 1d - receptors can be found in the distal ureter . in this study , the rr for lower ureter stones ( rr , 1.50 ; 95% ci , 1.20 to 1.88 ) was higher than that for upper ureter stones ( rr , 1.31 ; 95% ci , 1.02 to 1.68 ) in the subgroup meta - analysis . several systematic reviews and meta - analyses have already demonstrated the effectiveness of tamsulosin in facilitating stone clearance in both patients being managed by watchful waiting and patients after swl . seitz et al .   reported a higher rate of stone expulsion in watchful waiting patients treated with either 0.2 mg ( rr , 1.56 ; 95% ci , 1.21 to 2.03 ) or 0.4 mg ( rr , 0.40 ; 95% ci , 1.28 to 1.54 ) of tamsulosin . they also demonstrated that swl plus tamsulosin ( 0.4 mg ) was more effective than swl alone ( rr , 1.38 ; 95% ci , 1.22 to 1.56 ) by meta - analysis . in the meta - analysis performed by zheng et al . , a 24% ( rr , 1.24 ; 95% ci , 1.12 to 1.37 ) improvement was demonstrated in stone clearance by tamsulosin after swl for renal and ureter stones . the tamsulosin group had a shorter expulsion time , lower analgesic requirements , and fewer colic episodes and adverse effects . a meta - analysis performed by zhu et al .   showed a 16% rd of stone clearance after swl , favoring the tamsulosin group over the control group . in addition , the expulsion time was shortened by 8 days in the tamsulosin group . however , no conclusive evidence exists of the effectiveness of tamsulosin for stone clearance in korean patients . the results of the present meta - analysis showed that a 0.2-mg dose of tamsulosin is effective in enhancing stone expulsion in korean patients . the pooled analysis showed a 43% higher expulsion rate in the tamsulosin group than in the control group . the rcts included were mostly small , single - center studies ; therefore , the results were inconclusive or partly significant . however , more conclusive evidence can be generated by a meta - analysis of these rcts . similar to korea , low - dose tamsulosin of 0.2 mg is the usual accepted dose in japan . two rcts have evaluated the efficacy of a 0.2-mg tamsulosin dose in met for ureteral stones in a japanese population . the low dose of tamsulosin shortened the stone expulsion time ( 15.666.14 days vs. 35.4753.70 days , p=0.0424 ) in japanese men with ureteral stones after swl . however , the stone expulsion rates were not significantly different ( 84.21% vs. 88.24% , p=0.34 ) . concerning the watchful waiting setting , 0.2 mg of tamsulosin significantly facilitates ureteral stone clearance ( 77% vs. 50% , p=0.002 ) in japanese men . these data further support our results , because all studies were conducted with the 0.2-mg dose of tamsulosin in a far east asian population . most studies were predominantly small , single - center trials that did not present the power calculations needed . again , only one report described the randomization method used , and none of the reports presented dropouts . owing to the qualities of the included studies , the pooled analysis could be affected . as the funnel plot suggested , studies with a negative result seemed to be unpublished . we could not compare the duration of stone expulsion or the degree of colic pain . only one study described the expulsion duration , and there was no standardized reporting protocol for pain . furthermore , a study that evaluates pain and adverse events should be placebo - controlled and double - blinded . we could not evaluate the dose - response relationship of tamsulosin in stone clearance that was suggested by other articles . there is some evidence that a combination of tamsulosin and other agents , such as corticosteroids , might be more effective than -blockers alone . future studies should focus on the dose - response relationship of tamsulosin and its combination with other drugs . despite the abovementioned potential limitations , this study provides the highest level of evidence to date from rcts conducted with korean patients . to the best of our knowledge , this is the first well - performed meta - analysis that has incorporated rcts conducted with only korean patients in a urologic field . these results support the use of tamsulosin for the ureteral stone patients who are commonly encountered in the urologic clinic . the results of the present meta - analysis suggest that treatment with tamsulosin facilitates the stone expulsion rate for ureter stones with or without swl in the korean population . despite the high level of evidence provided by this meta - analysis of rcts , there was a lack of well - designed , high - quality prospective studies . more information should be assessed , and large - scale , multicenter , placebo - controlled rcts should be performed in the future .
purposeusing meta - analysis , the study 's aim was to evaluate the efficacy of tamsulosin , an alpha - blocker , in the treatment of ureteral stones with or without shockwave lithotripsy ( swl ) in korean patients.materials and methodsrelevant randomized controlled studies published through june 2011 were identified in a search of medline , koreamed , and the korean medical database . 
 no language restriction was applied . only randomized controlled trials conducted with korean patients were eligible for the analysis . 
 the primary outcome assessed was the stone clearance rate . 
 two reviewers independently assessed the quality of the study and extracted the data . 
 meta - analysis was conducted by using r , version 2.13.0.resultsa total of 6 articles were selected as being suitable for evaluation . 
 pooling of the trials demonstrated a 43% higher expulsion rate for tamsulosin treatment compared to a control group ( risk ratio [ rr ] , 1.43 ; 95% confidence interval [ ci ] : 1.24 to 1.65 ) . 
 similar results were obtained in all subgroup analyses according to stone location ( upper : rr , 1.31 ; 95% ci , 1.02 to 1.68 , lower : rr , 1.50 ; 95% ci , 1.20 to 1.88 ) or concomitant swl ( yes : rr , 1.38 ; 95% ci , 1.14 to 1.68 , no : rr , 1.48 ; 95% ci , 1.21 to 1.83).conclusionsthis meta - analysis of randomized controlled studies provides a high level of evidence supporting the suggestion that treatment with tamsulosin augments the stone expulsion rate for ureter stones with or without swl in a korean population . however , a high - quality , large - scale , multicenter , randomized controlled trial is warranted to fully support this hypothesis .