Posted by: Nicholas Swetenham | March 20, 2009

Times misreports maggot therapy research

Ceci n'est pas une panacée

Lucilia sericata larvae

***Edit 24/03/2009***

Effect measure has got a good post on this.

***Edit 23/03/2009***

The Guardian has now got a layman’s summary of the paper. It’s published in association with the BMJ but nonetheless seems a fairly balanced summary.

***Edit 21/03/2009 13:40***

Changes: 1. Image caption changed to describe species. 2. Quoted both BBC and Times more extensively, with headlines, for fairer comparion. 3. Added paragraph below:

Let me just clarify that I think that while nothing in either report is untrue, the fact that the two headlines seem to be suggesting very different things about the study suggests that one of them is more balanced. The Times story focuses on debridement, rather than time to healing or pain. In the words of the study authors:

the study raises uncertainty about the role of debridement in the care of leg ulcers. Although debridement is viewed as an important part of preparationof the wound bed, data describing the relation between debridement and healing are sparse. Research is required to explore the relation between debridement, healing, and microbiology as well to better understand the value of debridement as an outcome from the patient’s perspective.

******

A randomised controlled trial on maggot therapy was published in this week’s British Medical Journal. The researchers’ conclusion:

Larval therapy did not improve the rate of healing of sloughy or necrotic leg ulcers or reduce bacterial load compared with hydrogel but did significantly reduce the time to debridement and increase ulcer pain.

Seen in the BBC as this:

Maggot therapy hope ‘premature’

Maggots may not have the miracle healing properties that have been claimed, a UK study suggests. Researchers comparing maggots with a standard “hydrogel” in treating leg ulcers found little difference…

…There was no significant difference in the time it took the ulcer to heal between the two treatments or in quality of life.

Maggots were not more effective than hydrogel treatment at reducing the amount of bacteria present or in getting rid of MRSA and were, on average, associated with more pain.

BBC

Compare with this:

When it comes to wound healing, the maggot cleans up

A study by a team of British scientists, published today, lends support to the use of the maggot in high-tech healthcare. They found that, left to graze on the skin, maggots can clean wounds that fail to heal five times faster than conventional treatments…

…Professor Nicky Cullum, a specialist in wound care, who led the maggot therapy study published in today’s British Medical Journal, said that maggots had cleaned wounds in 14 days — compared with 72 days with gel treatment. She said there was anecdotal evidence of increasing maggot use in the NHS.

The Times of London

It is a classic mistake in science reporting to fail to distinguish the subtleties in phrasing of positive vs. negative outcomes. While debridement was indeed faster the primary outcome – the wound’s actual healing – was no faster. And to top it off, the levels of pain reported were increased. This is certainly no miracle cure. If you read Nicky Cullum’s letter to the BMJ from 2006 entitled Not so fast with vacuums and maggots as firstline treatment you might also infer that the Times selectively quoted Prof. Cullum, who does not appear to be a maggot therapy enthusiast, to make it sound like she was supporting maggot use as first-line treatment.

I suspect that this story was intentionally misreported, in order to appeal to those readers who like the sound of maggots because they are ‘natural’. It is worth bearing in mind that maggots also ‘naturally’ cause disease by feeding on necrotic tissue – this is called fly strike or myiasis (warning: nasty pictures).

I have e-mailed this to Ben Goldacre at Bad Science.

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Responses

  1. In response to Nicholas Swetenham, I take issue with the suggestion that The Times is ‘misreporting’. Perhaps he is relying too heavily on the BBC, and having spoken to both the author of the paper, and read the paper (it would appear he has done neither), I would suggest he is a little too quick to judge. Nicky Cullum’s research showed that debridement occured in 14 days with maggots compared to 72 days with the conventional treatment, hydrogel (I generalise slightly with ‘five times’). The findings also show that wound healing happened as quickly with maggot therapy as hydrogel, itself an interesting finding – the first time maggots have been shown to be as effective in a randomised controlled trial.
    Prof Cullum said that maggot usage was ‘increasingly widespread’ (quote) in the NHS. She also observed that if quick wound cleaning was required, maggots could offer a clinical benefit.
    Whether Prof Cullum is (or is not) an advocate of maggot therapy (I do not know), the research speaks for itself. And if you want to compare reports against the BBC (not always accurate), you can just as easily compare with Maria Cheng of the Associated Press…

    ………………
    LONDON (AP) _ In a study testing treatments for leg ulcers, British doctors found that a surprising, yet perhaps revolting, option works just as well as standard treatment: maggots.

    Patients were either treated with a gel commonly used for ulcers or with maggots. The maggots were bred in sterile conditions and were about the size of a grain of rice. The insects were either packed into a teabag-sized packet or corralled into the wound with bandages.
    Patients who got the maggots healed just as quickly as those who got the gel, but suffered a little more pain in the process. The research, along with another study that said maggots were as cost-effective as the gel, was
    published Friday in the BMJ.
    ………………….

    Why not assume The Times is not misreporting, and that other (unbylined, non-specialist) reports might occasionally misrepresent instead?

    Yours,

    Sam Lister (Health Editor, The Times)

    • Dear Mr Lister,

      Thank you for your comment.

      I believe the correct reporting of medical journal articles requires a lot of care and subtlety to produce a story that is both true to the research and appealing to the reader. The Times article, in my view, exaggerated the benefits of maggot therapy over hydrogel by focusing on the faster debridement rather than the primary outcome of healing time, or the secondary outcomes of pain and rates of staphylococcus aureus infection. It is unlikely that maggots will be adopted as a conventional treatment for ulcers in the near future, so this article might give patients the wrong impression that they should request maggot therapy because it is ‘better’. The idea of using maggots for rapid debridement before surgery is indeed interesting but requires additional research before it can be confidently used in medical practice.

      I think that the Times usually does at least as good a job as other UK newspapers when reporting health, but I found that this particular story was not as good as it could have been.

      Best wishes,

      Nicholas Swetenham

  2. Nicolas:

    I think you didn’t quote enough from the Times article since the paragraph following the first one you quoted says:

    —-
    In a trial to investigate the clinical effectiveness of maggots for wound treatment, the leg ulcers of patients treated with larvae were found to heal just as quickly as the water-based gel normally used. The study also showed that the process of debridement — the removal of dead tissue, in this case eaten by the maggots — occurred far faster, suggesting that larvae could be used to clean sites at high speed before urgent surgery, such as skin grafts.
    —-

    You complained that:
    —-
    It is a classic mistake in science reporting to fail to distinguish the subtleties in phrasing of positive vs. negative outcomes. While debridement was indeed faster the primary outcome – the wound’s actual healing – was no faster.
    —-

    However this WAS reported!

    My take on your report: “Move along, nothing to see here”

    • Felix: I agree It was reported, but the overall impression given by the headline and the body of the text exaggerate the benefits of maggot therapy.

  3. I think that by failing to mention that the maggot treatment increased the pain of the ulcer results makes an otherwise good article slightly unbalanced.
    I also think that it should have been made clear that the primary measurable outcome for the trial was the healing time and that the time to debridement, like ulcer related pain, was secondary.

  4. I speak from personal experience with maggot therapy. I faced certain amputation and had tried all conventional methods at the time. (9 yrs ago) Being a diabetic, with poor circulation, on immuspressants and osteomyelitis(bone infection) I was told I had no choice or options. I by chance learned of maggot therapy and asked my doctors to consider using this to save my limbs. (Ulcers were on both feet.) They told me it would never work for me and only did to prove me wrong. Well, I proved them wrong. Maggots went into the tunneling and closed the tunneling up and came back out. They worked on the bone and healed the bone infection. They excreted enzymes to promote healing and totally healed my wounds up in approx 6 mos. This was an ulcer on my heel down to bone 2.5 cm. deep and 5.1 cm around. I barely have a scar now and have been healed eight years. There has been many studies in America showing the efficiency of maggot therapy. I suggest one do the research to learn the TRUTH about maggot therapy. They are cost effective and cost under $100.00 here in America. The antibiotics I was on for the bone infection all gave me bad side effects. One gave me a deadly bone marrow disease. Maggot therapy has no side effects! As far as pain… Yes, there was pain but it was better than amputation pain. IF I ever get another ulcer, maggot therapy would be my first choice not my last. I highly recommend maggot therapy to anyone for any non-healing wound. Maggot therapy is used for not only diabetic ulcers, but also gangrene, pressure ulcers, and infected burns. There is no product man can come up with that does all that maggot therapy can do.
    1 Eat just the dead infected tissue (not the good like surgery)
    2. Kill all the bacteria.
    3. Excrete enzymes to promote healing.
    I wish everyone would do their research and learn what I did. Maggots are amazing little creatures that can do miracles. Like they did for me.


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