This is a plain English summary of an original research article
This large, high quality trial found that people with a single kidney stone taking tamsulosin or nifedipine drugs for up to four weeks were no more likely to pass the stone spontaneously than those taking a placebo. This suggests that these drugs should not be offered to people with renal colic who are managed with a "watch-and-wait" approach.
About 80% of participants in either arm of this trial were able to pass the stone spontaneously, without a further procedure.
The prevalence of kidney stones in high income countries has increased over the last 20 years. Problems with stones were associated with 25,000 hospital admissions in England in 2012, costing £11.6 million.
Why was this study needed?
The number of cases of kidney stone disease is rising. Lifetime risk is about 12% in men and 6% in women. Renal colic is a type of severe abdominal pain caused by kidney stones, and is a common reason for people to seek emergency care.
Two previous meta-analyses (2009 and 2012) concluded that tamsulosin and nifedipine helped people with renal colic to pass stones. However, they emphasised these results may not be reliable due to limitations in the sample size and quality of the included trials. The NIHR funded this trial called SUSPEND, to resolve the uncertainty about the benefit of tamsulosin and nifedipine in the routine care of people with renal colic. This trial set out to establish whether these drugs increased the likelihood of spontaneous stone passage, and if so, which drug was better.
What did this study do?
The NIHR funded, SUSPEND study was a randomised, placebo-controlled trial recruiting 1,167 adults with renal colic across 24 NHS hospitals. They were randomly assigned to receive up to 4 weeks' daily treatment with either tamsulosin (400 micrograms), nifedipine (30 milligrams) or placebo. The primary outcome was spontaneous stone passage by four weeks, as defined by needing no interventions to help the stone pass. Participants, clinicians and trial personnel were not aware of treatment allocation. This was a large, well designed randomised controlled trial conducted in a routine care setting which allows for direct translation of its results into standard clinical practice.
What did it find?
- Neither drug had significant effect on the likelihood of spontaneous stone passage compared with placebo. Further intervention was not needed by 80% of the placebo group compared with 81% of the tamsulosin group (adjusted risk difference 1.3%, 95% confidence interval -5.7 to 8.3) and 80% of the nifedipine group (adjusted risk difference 0.5%, 95% CI -5.6 to 6.5).
- There was also no significant difference in intervention rates comparing tamsulosin with nifedipine (adjusted risk difference 0.8%, 95% CI -4.5 to 6.1).
- Results were adjusted for stone location, size and hospital.
- There were no differences between the three groups in other outcomes: need for pain relief, time for the stone to pass, or health status of participants.
What does current guidance say on this issue?
NICE Clinical Knowledge Summaries (2015) on the management of acute renal colic states that drug treatments – "medical expulsive therapy" (MET) - with either an alpha-blocker such as tamsulosin or a calcium-channel blocker such as nifedipine may be used to try and facilitate spontaneous stone passage.
Guidelines from the British Association of Urological Surgeons (2008) and the European Association of Urology (2015) also recommend that MET with tamsulosin and nifedipine can increase the likelihood of stone passage and thus reduce the need for further interventions. These drugs may be used as part of routine clinical practice but are not licensed for this particular use. This means that this is an "off-label" use.
What are the implications?
The trial was large, methodologically robust and addressed a population and decision problem representative of clinical practice. The results imply that tamsulosin and nifedipine should not be offered to people with renal colic who are managed with a “watch-and-wait” approach. Renal colic is a common and very painful condition. Drug treatments that help stone passage would still be beneficial for the 20% of people in this trial who went on for further intervention to remove the stone. Current guidance on this issue may need to be reconsidered.
Pickard R, Starr K, MacLennan G et al. Medical expulsive therapy in adults with ureteric colic: a multicentre, randomised, placebo-controlled trial. Lancet. 2015 May 18. [Epub ahead of print].
This research was funded by the National Institute of Health Research under the Health Technology Assessment programme (project number: 08/71/01).
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