Can MET smooth the rocky road to recovery?


Its summer in Yorkshire and fine folk are sweating under the shining golden orb, drinking too much beer and forgetting to wear sunscreen. But good grief its beautiful.

Its been while since I posted – I’ll be honest I’ve been focusing on my life with family in ‘the real world’ through a new addition to the family and bereavement in short space of time.

Something about the sunshine makes me think more about renal stones, maybe its that more people come in with them, or maybe its my own bias as i think people with belly pain are more likely to have a stone due to increased insensible losses and not replacing the volume well enough. Other than with the aforementioned beer.

For JC this month I picked an ‘oldie but goodie’ – it was reviewed in a umber of places including by us on RCEMLearning (here), along with a paper on a novel therapy for renal stones……
Again this paper was picked in a concerted effort to not focus on the ‘sexy’ resus room niche topics of airway and trauma resucictation that seem to dominate the #FOAMed thats out there – let me know if this is poppycock and you want reviews on that stuff instead!!

Title of the Paper: Medical Expulsant therapy (MET) in adults with ureteric colic: a multicentre, randomised, placebo controlled trial.

Published: Lancet 2015

The next patient is a 40 year old gent. He’s had pain in his left flank for about 12 hours. He’s unable to get comfortable despite taking oral analgesia at home, he’s rolling around on the trolley like he’s in the latter stages of labour. Examination reveals a tender left flank, hes afebrile and passes urine with moderate microscopic haematuria. He settles with rectal voltarol, you image him with a CTKUB which reveals a 6mm stone in the VUJ – there’s some debate about whether we should reach straight for CT or US or POCUS in these cases – what do you do?. His pain settles with rectal voltarol, bloods are normal and he’s keen for home – you agree with a plan for follow up in stones clinic in a few days. The urologist asks you to send him home with Tamsulosin stating it will increase the chances of him passing the stone……does it?

Clinical Question: In patients with confirmed ureteric stones do Medical expulsant therapies increase stone passage rates?

Population: Adults 18-65 with one stone identified <10mm on CTKUB. Intervention:: Tamsulosin or Nifedipine.
Comparitor: Placebo.
Outome: Spontaneous passage at 4 weeks.

The intervention: They had over-encapsualted medications prepared for this trial at doses of Tamsulosin 400 micrograms, Nifedipine 30milligrams or placebo. The write up doesn’t specifically mention whether these were made to look like each other so we’re not sure whether participants or researchers could become aware of what treatment arm they were assigned to. Pragmatically they set the upper age cut off for inclusion at 65 due to the advice that nifedipine is ‘up-titrated’ in this age group due to the potential for side effects.

Rnadomisation: This was well done with 1:1:1 allocation via a distant computer based software package. This is probably the modern gold standard of randomisation with minimal opportunity for bias to be introduced. Thier algorithim included centre, stone size and stone location to try and evenly spread confounders. They then planned to analyse the groups patients were randomised to.

Generalisability: This was a UK based paper so the patients probabaly reflect people we see. However, and this isn’t clear in the write up, these were not ED patients. Having been through the JC I contacted the authors and they confirm these patients were picked up in the ‘stones clinic’ having first been worked up in ED. Its not clear what happened to other patients that the feeder EDs saw -as the numbers are quite low 1200 patients across 24 centres over 2 years. That’s 25 patients per centre per year. Anecdotally, we see more renal stones than that, we send most of our stones patients for follow up, i wonder whats different about those that didn’t get followed up in these centres, or those that weren’t enrolled…..

Results: The authors recruited 1167 patients across the three groups with an equal spread across the intervention groups. They lost 14 to follow up and 17 were excluded later (not sure why). The headline is that across the groups there was NO DIFFERENCE between those given a MET and those given placebo – essentially 80% spontaneous passage rates. These findings were similar even when focused on to sex, stone size or location. NO DIFFERENCE. They also found no difference between secondary outcome measures of analgesic use and time to stone passage. They didn’t display data but found no difference to stone passage rates at 12 weeks.

The figure below is from the paper and highlights these findings across the groups.

For me this paper was a well conducted study, it met it’s power calculation requirements, their prediction of passage rates was reasonable, as were the inclusion criteria. I would like to see a similar study done with undifferentiated ED patients who are diagnosed with kidney stones, or at least I’d like to know what the centres in the trial did with the rest of their confirmed stones patients. It also feels like a victory for quality publishing to see a ‘negative’ trial given an Open Access slot from The Lancet. Chapeau.

My next job is to read the below and the Cochrane review and engage with team urology here in God’s county. If these findings are replicated elsewhere I’m going to struggle to justify prescribing Tamsulosin for my patients with a confirmed stone.


Keep Fighting the Good Fight



May 2016: New in EM


(Prof McClinton’s recommended reading)

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