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Open Access Study protocol

Use of drug therapy in the management of symptomatic ureteric stones in hospitalized adults (SUSPEND), a multicentre, placebo-controlled, randomized trial of a calcium-channel blocker (nifedipine) and an α-blocker (tamsulosin): study protocol for a randomized controlled trial

Sam McClinton12*, Kathryn Starr23, Ruth Thomas3, Graeme McLennan3, Gladys McPherson3, Alison McDonald3, Thomas Lam12, James N’Dow12, Mary Kilonzo4, Robert Pickard5, Ken Anson6, Jennifer Burr7 and the SUSPEND Study Group

Author Affiliations

1 Aberdeen Royal Infirmary, Foresterhill, Aberdeen AB25 2ZN, Scotland

2 Academic Urology Unit, University of Aberdeen, Health Sciences Building, Foresterhill, Aberdeen AB25 2ZD, Scotland

3 Health Services Research Unit, University of Aberdeen, Health Sciences Building, Foresterhill, Aberdeen AB25 2ZD, Scotland

4 Health Economics Research Unit, University of Aberdeen, Polwarth Building, Foresterhill, Aberdeen AB25 2ZD, Scotland

5 Institute of Cellular Medicine, Newcastle University, Newcastle Upon Tyne NE2 4HH, England

6 St George's Hospital, London SW17 0QT, England

7 Department of Medical & Biological Sciences, University of St Andrews, St Andrews KY16 9TF, Scotland

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Trials 2014, 15:238  doi:10.1186/1745-6215-15-238

Published: 20 June 2014

Abstract

Background

Urinary stone disease is common, with an estimated prevalence among the general population of 2% to 3%. Ureteric stones can cause severe pain and have a significant impact on quality of life, accounting for over 15,000 hospital admissions in England annually. Uncomplicated cases of smaller stones in the lower ureter are traditionally treated expectantly. Those who fail standard care or develop complications undergo active treatment, such as extracorporeal shock wave lithotripsy or ureteroscopy with stone retrieval. Such interventions are expensive, require urological expertise and carry a risk of complications.

Growing understanding of ureteric function and pathophysiology has led to the hypothesis that drugs causing relaxation of ureteric smooth muscle, such as the selective α-blocker tamsulosin and the calcium-channel blocker nifedipine, can enhance the spontaneous passage of ureteric stones. The use of drugs in augmenting stone passage, reducing the morbidity and costs associated with ureteric stone disease, is promising. However, the majority of clinical trials conducted to date have been small, poor to moderate quality and lacking in comprehensive economic evaluation.

This trial aims to determine the clinical and cost-effectiveness of tamsulosin and nifedipine in the management of symptomatic urinary stones.

Methods/design

The SUSPEND (Spontaneous Urinary Stone Passage ENabled by Drugs) trial is a multicentre, double-blind, randomized controlled trial evaluating two medical expulsive therapy strategies (nifedipine or tamsulosin) versus placebo.

Patients aged 18 to 65 with a ureteric stone confirmed by non-contrast computed tomography of the kidney, ureter and bladder will be randomized to receive nifedipine, tamsulosin or placebo (400 participants per arm) for a maximum of 28 days. The primary clinical outcome is spontaneous passage of ureteric stones at 4 weeks (defined as no further intervention required to facilitate stone passage). The primary economic outcome is a reduction in the incremental cost per quality-adjusted life years, determined at 12 weeks. The analysis will be based on all participants as randomized (intention to treat). The trial has 90% power with a type I error rate of 5% to detect a 10% increase in primary outcome between the tamsulosin and nifedipine treatment groups.

Trial registration

ISRCTN69423238; EudraCT number: 2010-019469-26

Keywords:
medical expulsive therapy; nifedipine; tamsulosin; ureteric stone