Abstract: PNFLBA-04
Sources of Funding: The STONE Study is supported by cooperative agreement U01 DK096037 from the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (Pilot Study RO1 DK071603, Planning Grant U34 DK090957). The study is registered at clinicaltrials.gov (NCT00382265).

Introduction

Urinary stone disease (USD) is common, increasing with many patients first presenting to the emergency department (ED). Use of alpha-adrenergic receptor antagonists (alpha-blockers) has been advocated to promote passage of urinary stones. We conducted a multi-center, double-blind, placebo-controlled clinical trial of the alpha-blocker tamsulosin in ED for ureteral stones less than 9 mm in diameter.

Methods

Patients presenting to five EDs with USD confirmed by non-contrast spiral computed tomography (CT) were randomized equally to receive tamsulosin 0.4 mg daily or placebo. The primary outcome was stone passage, determined by either visualization or capture by the study participant, within 28 days of randomization. The primary outcome analysis compared binomial proportions for each of the two treatment groups using a chi-square test statistic. Secondary outcomes were confirmation of stone passage on follow-up CT in a subgroup (n=237), need for surgical intervention, crossover to open-label tamsulosin, and days of work lost.

Results

We randomized 512 participants. The mean ± standard deviation (SD) age was 40.6 ± 13.3 years. Symptomatic urinary stones were identified in the following locations: 45% ureterovesical junction, 24% distal ureter, 10% mid-ureter, 17% proximal ureter and 3% renal pelvis. The mean ± SD diameter of the symptomatic stone was 3.8 ± 1.4 mm (range, 1 mm to 8 mm). The proportion of study participants who had passed a stone by day 28 (outcome determined in 97% of those randomized) was 52% in the tamsulosin group and 49% in the placebo group (relative risk 1.07, 95% confidence interval 0.90-1.28; p=0.447).

Conclusions

The proportion of patients who had passed their urinary stones at day 28 did not differ significantly between tamsulosin and placebo. The trial was not designed to detect stone passage according to stone location. Our results do not support the use of this drug to promote passage of urinary stones less than 9 mm in diameter.

Funding

The STONE Study is supported by cooperative agreement U01 DK096037 from the National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (Pilot Study RO1 DK071603, Planning Grant U34 DK090957). The study is registered at clinicaltrials.gov (NCT00382265).