A canna’ change the laws of physics

Scotty, The Naked Time, stardate 1704.3, Episode 7

Plethora or paucity? The BCA and bedwetting

Posted by apgaylard on June 18, 2009

bigstockphoto_Xray_Spine_488820The BCA have, at last, released their much heralded “plethora” of evidence.  They preface this with an incredible statement, which includes the following gems: 

“In the spirit of a wider scientific debate, and having taken appropriate professional advice, the BCA has decided that free speech would be best facilitated by releasing details of research that exists to support the claims which Dr. Singh stated were bogus. This proves that far from there being “not a jot of evidence” to support the BCA’s position, there is actually a significant amount. 

It has never been the BCA’s case that the evidence is overwhelmingly conclusive. It is the BCA’s case that there is good evidence. […] 

[…] The BCA welcomes full, frank and open scientific debate. […]”

That’s good then, the BCA will welcome my frank take* on their summary of the evidence for chiropractic helping children with nocturnal enuresis. 

The BCA’s Evidence on Enuresis 

“16.     Glazener CM, Evans JH, Cheuk DK. Complementary and miscellaneous interventions for nocturnal enuresis in children. Cochrane Database Syst Rev 2005 Apr 23; 2: CD005230.

There was weak evidence to support the use of [chiropractic].”

This review actually said: 

“[…] Complementary treatments such as hypnosis, psychotherapy, acupuncture and chiropractic may help, but the evidence was weak. Further research is needed.” 

And under “Implications for practice”: 

“There was weak evidence to support the use of hypnosis, psychotherapy, acupuncture and chiropractic but it was provided in each case by single small trials of dubious methodological rigour.

[…] When standard effective therapies such as enuretic alarms have failed or are contra-indicated, these complementary therapies might be considered after careful discussion with parents. Parents should be thoroughly informed of the uncertain effectiveness and possible adverse effects of these alternatives. In addition, these complementary therapies should be administered on a research basis as part of a randomised controlled trial whenever possible, with efficacy and adverse effects carefully monitored.”

 This might be more than a jot of evidence, but it’s of poor quality.  I’d really like to believe that chiropractors thoroughly inform parents of the, “uncertain effectiveness and possible adverse effects” of this chiropractic treatment; along with administering the treatment “on a research basis”.  After all, they cite this review as a key item of evidence that supports their practise.  It would be hypocritical if its recommendations were not followed. 

The next item of evidence on this topic (Reed et al, 1994) was part of this review.  So here we have some double-counting: a review plus part of the evidence covered in the review are counted separately. 

“21.     Reed WR, Beavers S, Reddy SK, Kern GJ. Chiropractic management of primary nocturnal enuresis J Manipulative Physiol Ther 1994 Nov; 17(9)

Wet nights were significantly reduced after spinal manipulation. The study ‘strongly suggests’ the effectiveness of chiropractic treatment for primary nocturnal enuresis.” 

Wet nights were not “significantly reduced” with respect to the control group.  The only significant reduction was obtained by comparing the treated group’s initial wet night frequency with that determined after the ten-week treatment period.  In fact, “The mean pre- to post-treatment change in the wet night frequency for the treatment group compared with the control group did not reach statistical significance (p = 0.067).” 

The key comparison of the “treatment” and “control” groups did not reach statistical significance.  This is a negative trial.  It’s also a small trial (n=57) with some significant methodological flaws, such as not providing details of the method of randomisation. 

Crucially, only eight out of 31 treated children were deemed to be successfully treated (50% improvement) – that’s 26%.   Even if this effect is real, it doesn’t compare well with  the use of alarms (Glazener, Evans and Peto, 2005): 

[…] The review of trials found 56 studies involving 3257 children. Alarm interventions reduce night-time bed wetting in about two thirds of children during treatment, and about half the children remained dry after stopping using the alarm. […]” 

No wonder the Cochrane review recommends that if chiropractic is used it is only used where, “standard effective therapies such as enuretic alarms have failed or are contra-indicated”. 

So it’s a small, poor-quality study with a statistically insignificant result of limited clinical relevance: weak indeed. 

“22.     Blomerth PR. Functional nocturnal enuresis. J Manipulative Physiol Ther 1994; 17: 335-338.

The patient’s enuresis resolved with the use of manipulation. This occurred in a way that could not be attributed to time or placebo.”

 This article describes a single case study: 

“The lumbar spine of an eight-year-old male bed wetter was adjusted once and at a one-month follow-up. There was a complete resolution of enuresis.  This happened in a manner that could not be attributed to time or placebo effect.”

 The author notes that, “The patient had several recurrences of bed-wetting” but and opines that, “all of which were associated with minor injury to the lower back.”  It is a bit much for the author to have us take this on trust.  

The claim that, “This happened in a manner that could not be attributed to time or placebo effect” is very odd.  Without a time-machine, how could the author be sure? 

And that, as far as the BCA are concerned, is that: a review that calls the evidence “weak” and notes that it is based on “a single small trial[ ] of dubious methodological rigour”, the dodgy trial in question and a single case study.  I’d call this a paucity of evidence. 

What the BCA Missed

Because the BCA has just cherry-picked** what it obviously considers the most compelling evidence, several other studies have been missed off the list.  For example, the Cochrane review also cited Leboeuf et al (1991)

This was a unblinded “prospective outcome study” which looked at, “[o]ne hundred and seventy-one enuretic children, aged 4 to 15” who were, “were treated with chiropractic adjustments”.  The outcome measure was the number of “wet nights” which was monitored by their parents. 

With the children acting as their own ‘controls’ the number of “wet nights” had decreased during a two week period with no treatment from a median of seven per week to 5.6 (p = .01).  By the end of the treatment this was 4.0 per week (p less than .0001). 

This means that after 2 weeks without treatment the median rate of “wet nights” had already fallen by 1.4 per week.  It would appear that the treatment phase lasted a further 2 weeks, during which time the median rate of “wet nights” fell by a further 1.6.  This is a further reduction of 0.2 “wet nights” per week, compared to the initial rate, which seems deeply unimpressive for a condition that generally tends to improve with time. 

So, was this a success? Not according to the authors: 

 “This result is less favourable than the therapeutic success of other common types of therapy, which have reported “cure” rates well above 50%.  

[…] In the absence of a control group there appears to be no validity in the claim that chiropractic is a treatment of choice for functional nocturnal enuresis.”

[…] The only variable which predicted treatment outcome was the initial estimate of bed-wetting; the more severe the condition at the onset, the less likely was the child to improve by the end of the study […]  

They also neglect to mention a review by Kreitz and Aker (1994).  This concluded that: 

 “The success of each therapeutic option must, in part, be attributed to the natural history of enuresis, as well as any educational or placebo aspects of treatment. Conditioning therapy utilizing the urine pad alarm may be the most reasonable initial mode of intervention. Spinal manipulative therapy has been shown to possess an efficacy comparable to the natural history.”  

I take it that this means that chiropractic works as well as leaving the child alone. 

It’s also worth noting that, contrary to the protestations of Richard Brown, the vice-president of the BCA, this research is all about attempting to treat a non-spinal condition by spinal manipulation.  No wonder there’s paucity, rather than a plethora, of evidence. 

My conclusion is that there’s not a jot of robust evidence that chiropractic manipulation can help relieve nocturnal enuresis. 

Disclaimer

This does not constitute medical advice.  If you need that please consult a medical doctor. 

Notes

*This piece is largely based on a previous post.

**An honest mistake, I’m sure. 

References

Blomerth PR. Functional nocturnal enuresis. Journal Of Manipulative And Physiological Therapeutics. 1994 June;17(5):335–338. Available from: http://view.ncbi.nlm.nih.gov/pubmed/7930968.

Glazener CM, Evans JH, Cheuk DK. Complementary and miscellaneous interventions for nocturnal enuresis in children. Cochrane Database Of Systematic Reviews (Online). 2005;(2). Available from: http://dx.doi.org/10.1002/14651858.CD005230

Glazener CM, Evans JH, Peto RE. Alarm interventions for nocturnal enuresis in children. Cochrane Database Of Systematic Reviews (Online). 2005;(2). Available from: http://dx.doi.org/10.1002/14651858.CD002911.pub2.

Kreitz BG, Aker PD. Nocturnal enuresis: treatment implications for the chiropractor. Journal Of Manipulative And Physiological Therapeutics. 1994 September;17(7):465–473. Available from: http://view.ncbi.nlm.nih.gov/pubmed/7989880

Leboeuf C, Brown P, Herman A, Leembruggen K, Walton D, Crisp TC. Chiropractic care of children with nocturnal enuresis: a prospective outcome study. Journal Of Manipulative And Physiological Therapeutics. 1991 February;14(2):110–115. Available from: http://view.ncbi.nlm.nih.gov/pubmed/2019820

Reed WR, Beavers S, Reddy SK, Kern G. Chiropractic management of primary nocturnal enuresis. Journal Of Manipulative And Physiological Therapeutics. 1994;17(9):596–600. Available from: http://view.ncbi.nlm.nih.gov/pubmed/7884329

Edits

None Yet!

[BPSDB]

About these ads

10 Responses to “Plethora or paucity? The BCA and bedwetting”

  1. [...] canna’ change the laws of physics blog takes a look at the studies dealing with bed wetting and unbelievably finds they aren’t quite as persuasive as the BCA claimed. Who would have [...]

  2. dvnutrix said

    As ever, thorough, analytical, nicely-referenced work. Congratulations on another fine piece.

    • apgaylard said

      Thanks. It’s mostly a re-packaging of bits of a previous post, but the BCA statement does provide an interesting, if disappointing, context. I must admnit to being fascinated by the “we’re not just back crackers” defence of Richard Brown and the “back cracking really works” strategy of the BCA, on the same topic of the Singh litigation and non-spinal conditions. I wonder whether this is just a single bad strategy or various bits of the BCA are not co-ordinating.

  3. [...] Gaylard of A canna’ change the laws of physics offers a thoughtful analysis of the studies dealing with bed wetting. They aren’t quite as persuasive as the BCA seems to argue that they [...]

  4. [...] Science Blogs Plethora or paucity? The BCA and bedwettingBritish Chiropractic Association (BCA) demonstrate what evidence-based medicine isn’tExperimenting [...]

  5. [...] of the BCA statement and aftermath. HolfordWatch – What would constitute good evidence? Apgaylard – A more detailed look at the bed-wetting papers. JDC – General comment on the BCA [...]

  6. [...] flagged up the BCA selectively quoting a Cochrane review. Every stone was turned by Quackometer, APGaylard, Gimpyblog, EvidenceMatters, Dr Petra Boynton, MinistryofTruth, Holfordwatch, legal blogger Jack of [...]

  7. [...] up the BCA selectively quoting a Cochrane review. Every stone was turned by Quackometer, APGaylard, Gimpyblog,EvidenceMatters, Dr Petra Boynton, MinistryofTruth, Holfordwatch, legal [...]

  8. [...] flagged up the BCA selectively quoting a Cochrane review. Every stone was turned by Quackometer, APGaylard, Gimpyblog, EvidenceMatters, Dr Petra Boynton, MinistryofTruth, Holfordwatch, legal blogger Jack of [...]

  9. [...] treat conditions that there is no evidence they can successfully treat: colic, ear infections, or bedwetting to pick just three [...]

Sorry, the comment form is closed at this time.

 
Follow

Get every new post delivered to your Inbox.

Join 596 other followers

%d bloggers like this: