Cherry picking
As I have written in my introduction, a lot of my colleagues claim to practice evidence based veterinary medicine. In reality, a lot of them practice profound cherry picking. If the evidence supports their opinions and experiences, they follow it. If it contradicts them, they ignore it.
Here is a collection of examples that I have encountered over the years. This collection is proudly subjective and obviously anecdotal, and by no means exhaustive.
- My all time favourite: ranitidine.
When I was still locuming, I often came into the situation that a lot of British vets liked to use ranitidine, a gastric acid blocker and H2-receptor blocker, for pretty much every gastroenteritis in dogs.
It often came to a conversation along those lines:
'You shouldn't be raw feeding, there is no evidence for the claimed benefits but good evidence for risks.'
(That statement is true, as it is. A bit more nuanced, there is mainly anecdotal evidence, and a few studies based on owner questionnaires. Not exactly no evidence, but all in all very weak evidence.)
'Fair enough, but talking about evidence, are you aware that there is evidence that ranitidine doesn't work in dogs, and that it is actually not indicated for a simple gastroenteritis?'
'Yes, I know, but it seems to help.'
There are two problems with this statement: first, you can use it for any intervention, including homeopathy and astrology. 'I know it's not working but I think it helps' is a contradiction in itself. Second, there is a BIG difference between doing something without having the evidence for a claimed benefit and doing something having the evidence that it does not work. And that's leaving the lack of indication aside.
- Antibiotics to treat cystitis in cats
As a background, cystitis in cats is rarely an infection. In young cats it virtually never is. In older cats, or if they have concurrent illnesses like kidney problems or diabetes mellitus this changes, but around 60 percent will still not have an infection.
Vets have known this for decades.
Yet at least a few years back when I was still exclusively doing locum work, a lot of vets in Britain routinely used antibiotics to treat them. Not uncommonly even using critically important antibiotics like cefovecin, because it comes as a conveniant 14 day lasting injection.
As one colleague put it, when I tried to discuss her approach to it: "Well, it works."
No, actually, it does not work. They just get better. Usually, they get better within 10-14 days whatever we do. Most other vets in the practice didn't give antibiotics unless there was proof of an infection (i.e. bacteria found in a sterile taken urine sample on microscopy or after bacterial culture) and our cats were getting better exactly the same.
Not to mention the scientific evidence and pretty much every official treatment recommendation.
- Cats and chronic gingivostomatitis
Most effective treatment of this condition is extracting every tooth, including any potentially retained roots. It resolves the problem in about 60-70% of the cases.
There is a medical treatment developed by some Australian vets. It is basically a triple medication (an antibiotic, an antiinflammatory and an antiviral) compounded into 1 liquid. The Australian vets claim they see really good results, even in cases where the tooth extractions did not work.
A client's cat had that problem and it was not certain whether she we would opt for full mouth extractions.
As a possible alternative I looked at this medication and asked a specialized dental clinic whether they had any experience with this treatment. Their answer was that they are aware of it but that they would not use it because there were no published, peer reviewed studies about its efficacy.
So far so good.
The only problem I have with this is, that they do propagate polishing teeth after scaling as absolutely necessary. Even though there is no published, peer reviewed study confirming the alleged benefits and necessity. On top of that there are some recognized risks, mainly if done incorrectly, and some evidence that any possible benefits are very short lived. In human dentistry they do not routinely polish anymore because the potential risks are seen as outweighing any potential benefits.
Again, that is cherry picking. In this case not cherry picking the evidence but which treatment is acceptable, even necessary, in the absence of evidence.
- diarrhoea and hge (haemorrhagic gastroenteritis) and antibiotics
most every study looking into these two illnesses found that antibiotics virtually never make a difference in regards to how quick and how well the animals recover.
Yet a lot of vets still use antibiotics routinely, especially for hge.
- another topic is routine diagnostic screening, pre-operative blood tests in particular.
A lot of veterinary practices do sell these tests as critically important. Allegedly, some practices refuse surgery without them.
Studies looking into the benefits of these screening tests find that in the vast majority of cases (>>90%) these tests change neither approach nor outcome. Based on these studies pre-anaesthetic blood tests virtually only make sense if there is already a suspicion of illness, but not as a routine screening test for every animal that appears clinically healthy.
A second mistake often made in this context is the assumption that at worst there is no harm.
But:
1st, taking a blood sample is invasive and could lead to complications. While these are rare and usually minor, the risk is not zero.
2nd, psychological stress for the animal.
Taking a blood sample often is a stressful and somewhat painful experience.
3rd, psychological stress for the owner.
One of the most common arbitrary blood results is a mildly elevated liver enzyme. In itself that usually does not mean anything. What a lot of pet owners hear, though, is that the animal has a liver problem. And then further diagnostic tests follow, more or less invasive and potential risks as well as what comes as
4th, unnecessary financial cost. And in some cases, that money then is not available anymore for necessary diagnostics and treatments…
If you have any comment, feel free to drop me a line.