Animals v humans
I don’t really see much difference between animals and humans. To me they are both beings that can feel pain and suffering and deserve life, sustenance and medicine (or veti) care when they are ill. I’ve never eaten meat and I don’t really see the difference between eating animal flesh and human flesh. I didn’t become a vet because you have to be able to kill animals as a vet. During vet school you have to be able to go into a slaughterhouse and kill animals, and I knew I could never do that. I’m aware that most people do see a difference between animals and people but I can’t really see one. I often wonder what is this huge point that I’m missing. Usually when one holds an opinion that differs from 90% of other peoples then it is because one is wrong. The only difference I can see between animals and humans is the fact that they’re smaller, have less frontal cortex and are furrier. Babies are smaller and have less frontal cortex, though not as fury.
You know when you are in a minority, do you ever start to wonder if it might be you that’s wrong and the world that’s right. Something happened tonight to make me doubt my value system. Today I found my cat with a wild rabbit, I chased the cat away and found the rabbit not moving it’s back legs.Although there was no obvious injury it wasn’t moving its hind legs.My wife told me to let the cat finish the job. I didn’t I picked it up and stroked it. It was injured and needed care.
‘Well what are you going to do with it’ she said we’ve already got enough pets. ‘I don’t know’ I said, ‘put in the in the tortoise hutch and call my friend who’s a vet’.
‘if you do that we’ll can’t carry on living in the countryside, wild animals get injured all the time, and you can’t go taking them all to vets’.
‘If I don’t I won’t be me, I’m not the sort of person who leaves something who needs help, I’ll be a harder person, a more callous person’.
She rolled her eyes as I failed to get hold of two friends that were vets. I thought that they’d just tell me that it was hopeless, that I should just knock it on the head. I remembered seeing that the University department of veterinary medicine had a 24 hour on call service. it was a reasonable time. I could just talk to a vet, and they could tell me it was hopeless and nothing could be done. It turned out that the university Vet School has a 24 hour on call resident vet.
‘Oh, it does sound very poorly. it sounds bad, but bring it in and I’ll take a look at it’
So that was why I found myself in the Roslin institute (home of the first cloned sheep) at 10pm. There very nice vet agreed it was a very cute rabbit and decided that it was very poorly, but it might just be ok, so she’s going to give it a day or so of warming up, fluids and analgesia. All covered by the vet school’s injured wild animal fund.
So now it’s getting a chance, and my wife thought I should let the cat finish of the job. I’m disturbed that the person I share my life with could be that callous towards the suffering of another being because it wasn’t a human. It just reminded me that she’s fundamentally different from me. Despite eating Quorn and having Soya milk in her tea it’s all a pretence, she doesn’t see animals and being worthy of life and deserving of medical (or vet) care in the same way humans are. I knew she wasn’t vegetarian when I married her, so I just have to accept this.
And I struggle with the fact that I know that most people over the age of 4 disagree with me. So maybe it is me. Maybe I am stupid over animals. But when I look at them I can’t see that much of a difference, they’re all worthy of life. Given that I’m in such a minority there must be a huge fact I’m missing. I must be wrong here, it can’t be that everyone else in the world is wrong.
Junior Doctors, Your Registrar is there to stop you killing someone
I’m watching the new BBC3 series ‘Junior Doctors’ your life in their hands, and cringing. It’s all there. It’s all a bit too true. Like most doctors I remember my first day as if it were yesterday, and to be honest I wasn’t much use.
The fear, the sudden feeling that you someone needs to call a doctor, and that doctors is you. The fear that you don’t know what I’m doing. You feel when you go out there that you can kill someone. The cringining when you’re grilled by your Reg. It really feels very very scary, and it is very very scary. There’s 5 years of theory which needs to be applied to real life and common sense, and it’s a big job to put it all together. Some people just take to it like a duck to water, some people take a bit longer to get the hang of it all. They’re all making the mistakes that I’ve made, I didn’t see the point of paperwork at first and I probably came across as arrogant.
What’s interesting is that TV programmes are always with filming doctors seeming like they’re fumbling around during the first day of their new jobs. Doctor’s to Be, Cardiac Arrest, Casualty. It’s all there. What I don’t get is why they never film nurses on their first day in the job? I’ve worked with nurses on their first shift on their own, and I can assure you that it’s just as scary as watching doctors. I suspect it’s because nurses have more sense than to let themselves be filmed. Nurses, as a profession, have better PR.
Nurses love to tell you that they teach junior doctors what to do in August. And that’s true – sort of. They do teach you a lot of the practical aspects. Which pain killer works where, that sort of thing, some of them are good at recognising when patients are sick, some of them aren’t so good at that. But what they don’t teach you is how to diagnose and manage patients. They’ll tell you what they have seen other doctors doing, but that’s different.
Years later and I’ve seen many Augusts with brand new doctors, and what really surprises me is how easy it is to stop them killing someone. What they never show on TV is that there’s (nearly) always another doctor around, watching, keeping an eye on them, supporting them. It’s usually their friendly, or often not so friendly, registrar. They may not even realise how close an eye we keep on them. But every new admission seen by my juniors will be seen again by me, or at least discussed with me if it’s a straightforward case and they’re a bit more experienced. Every sick person on the ward should be discussed with me, and is usually seen by me. I didn’t see any registrar’s in the background of Junior Doctors, hovering, low key, keeping things safe.
I’m sure juniors don’t realise that my ‘little chat’s to see what they’ve been up to’, are actually to check that they’re not killing people’, when I ‘drop into the ward after a clinic’ it’s not to nick the Quality Street, it’s to check they’ve done the really important jobs, the quality street is an added bonus. If they’re getting a bit cocky, I might tell them that they ‘Could have killed someone’ or ‘were a danger and needed to pull their socks up’, I sometimes make them cry, and then I feel pleased, because I know that my message has sunk in. Actually the most important thing is that the patient’s still alive. Those that care listen without crying, those that need making cry need taking down a peg or two.
It wasn’t until four years after I graduated that I actually got to make decisions that weren’t discussed with, or reviewed by another doctor with in a few hours, or immediately if they were very sick. These guys feel alone, but they’re not, and it’s not the nurses stopping them killing people, it’s the other doctors. Although there’s a myth that death rates go up in August, I seriously doubt that happens in the modern NHS, junior doctors are more protected now than they ever have been before. They are very very rarely left alone and there is a very supportive culture. But ultimately you have to get out there and do it.
Natural Nonsense about Salt.
‘Doctors are wrong! Salt isn’t bad for you! In fact salt is essential for life. Unfortunately real salt is hard to find – table salt is poison- you need magic Himalayan Mountain Salt!’
I was recently sent a link on Facebook to this page about the benefits of natural salt. Specifically Himalayan Mountain Salt, a wonderful substance that cures all sorts of ills. Climbers have been known to use it to avoid hyperthermia.I’d have though that hyperthermia, (excessive body heat) isn’t too much of a problem if you are climbing the Himalayas. Unfortunately it isn’t effective against hypothermia, which is a common cause of death on Mount Everest. The article helpfully tells us more of the reasons we should be taking Himalayan Mountain Salt:
‘Hypertension and stomach cancer have been linked to dietary salt imbalance’: yes, hypertension at least has been linked to too much salt, but I don’t think that’s what he meant. Oliver continues : Cystic fibrosis has been linked to improper salt metabolism’ yes, cystic fibrosis is caused by a genetic mutation in a chloride transporter – but that’s not going to be helped by magic mountain salt.
So apparently we shouldn’t be cutting salt out of our diet – we should be buying magic mountain salt instead. Let’s look at some of the claims made about magic salt – mainly by websites selling it, and we’ll get to see some of the most common logical fallacies along the way;
We’ll start off with a cup of tea at ‘Shirley’s Wellness Cafe’ , maybe she’ll add salt instead of sugar. She begins by telling us
An eight-year study of a New York City hypertensive population stratified for sodium intake levels found those on low-salt diets had more than four times as many heart attacks as those on normal-sodium diets.
She doesn’t provide a reference – but she does say that the study was performed by Dr Jeffrey R. Cutler in 1995. If you search pubmed for ‘cutler[Author] AND 1995[Publication Date] ‘ you can’t find the trial she mentioned, but you can find a letter written by Dr Cutler, about another trial performed by some other people. I think the paper she’s referring to is ‘Low urinary sodium is linked with higher risk of myocardial infarction among treated hypertensive men’ . This is a study of 2937 patients in New York who were treated for hypertension - they stopped their hypertensive medication for 3 weeks, and had urinary sodium measured, then they went back on their anti-hypertensive medication. The patients who had a low urinary sodium, which was thought to indicate a low salt diet, were more likely to have heart attacks. This is an interesting study, but it doesn’ t prove that a low salt diet is bad. Firstly they assume that a low urinary sodium is caused by a low salt diet, it could be caused by an excess of plasma renin, which causes salt and water retention, and raises blood pressure. Secondly, everyone had their blood pressure treated aggressively; one of the reasons that salt is bad because it causes high blood pressure, and these people all had their blood pressure lowered with drugs. The logical fallacy Shirley’s fallen for is actually Cherry Picking.
Logical Fallacy : Cherry Picking
Yes, she has quoted one study that shows that salt might not necessarily be a bad thing, but she has ignored all the other studies that show that a high salt diet is dangerous. She’s just taken the evidence that she agrees with and ignoring the evidence that she disagrees with. Never mind – someone who runs a natural health cafe probably doesn’t know how to do a systematic review. Let’s look at the rest of the evidence cited by Shirley and her friends, and the logical fallacies that they illustrate.
Logical Fallacy - appeal to ancient knowledge:
Shirley tells us that Hippocrates made frequent use of salt, especially the use of saline inhalation for asthma. Hmm. Well I use saline nebulisers sometimes, but actually salbutamol nebulisers are better for asthma, saline nebulisers are useful if you have pneumonia and are struggling to cough stuff up. Firstly this is totally irrelevant to whether or not salt in the diet is safe, and secondly that this is an example of another logical fallacy.
Lots of proponents of alternative medicine use this argument, it’s a variation of ‘appeal to authority’. For example ‘Ancient people knew that willow bark was great for chest pain, so we should know that aspirin is a great treatment for angina’. Do I need to explain why this is nonsense? Why should ancient people have any greater knowledge that we have now? Ancient people certainly valued salt a great deal, and it was very expensive in the past. This was because they used salt to preserve food, and if you could preserve food in the autumn you wouldn’t starve to death in the winter. So what if you died of a heart attack at 70? – at least you lived until spring when you were 4.
Salt is essential for life! : Logical Fallacy – the straw man argument.
Relfe.com and other websites tell us that ‘salt is essential for life’. And they’re right, every cell in our body contains salt, nerves need sodium ions to transmit signals, our sweat and tears contain salt. If you have low sodium levels in our blood then you may die, but it’s almost impossible not to take enough salt in your diet. People who have low sodium in the blood have usually lost excessive salt through vomiting, or they have other medical problem.
Doctor’s don’t advise a totally salt -free diet, they advise a low salt diet – between 2-6grams of salt a day. The problem is that the modern person takes on average 9g of salt a day. Here people are using a straw man argument, they claim that doctors are saying something clearly stupid and attack the stupid argument.
Sodium Chloride is Poison : use special salt instead!
Many health food websites say that the problem with modern table salt is that it’s too highly refined, it contains just sodium chloride. However natural salt includes lots of other elements ’83 out of the essential 84 elements’ that means that it has special properties. There are two sorts of salt that seem to be promoted on the internet ‘Himalayian Salt’ and Celtic salt : french salt that is refined in a natural way. The websites that promote Celtic salt tend to quote someone called ‘Dr. Jacques de Langre Ph. D’ who has written a book promoting the benefits of it. He doesn’t seem to have written anything that’s been referrenced in Pubmed, maybe he’s too busy promoting his book.
Logical Fallacy : ‘The Lone Expert is Right’
A variation of ‘Appeal to authority’ loved by people who like alt-med is the lone expert fallacy. If 99 doctors say x is true and 1 doctor says y is true, then it must be that y is true, because the 99 doctors have been bribed by Big Pharma. Dr De Lange obviously believes that he is right, and the medical establishment is wrong. He believes that Celtic salt, which is dried in a special way will magically regulate blood pressure, it will lower it if it is too high, and raise it if it is too low. This is because it contains other essential trace elements such as magnesium which are lost in the refining process. As well as being an authority, he has a PhD you know, he quotes some people who have written to him.
Logical Fallacy: Anecdote
“Two weeks ago I donated blood at a Red Cross station. At that time my blood pressure was 160 over 90. ( Normal is 120 over 80). Yesterday, after hardly one week of using the Celtic salt, the only new addition to my diet, I recorded a blood pressure reading of 105 over 82”. A Patient who wrote to Dr De Lange
Humm. I can think of another explanation – maybe he was nervous about giving blood! That would have made his blood pressure go up when he donated blood, and appear to come down
Logical Fallacy Non- sequiture
Himalayian Salt Restores your Bodies Natural Ph: Natural Home Cures’ claims that Himalayian Mountain salt contains electrolytes which help prevent acidosis and alkalosis. They are right that acidosis and alkalosis are signs of serious illness, but salt and other minerals don’t do anything to regulate the bodies Ph. . That is done by a complex set of chemical balances performed by the lungs and the kidneys, using bicarbonate, and carbon dioxide, it’s nothing to do with sodium at all. You only get a derangement of your Ph when you are seriously ill – in an about to die sort of way.
Natural Home Cures Claims that
- Ph derangement is bad (True)
- Salt contains electrolytes which carry charge and affect Ph (true – but in a salt the electrolytes are balanced, so that isn’t going to affect an overal Ph).
- Therefore eating our salt can prevent Ph derangement. (Doesn’t follow).
And finally – the silliest claim of all! From Oliver’s Natural Health
Sole (so-lay), which is the mixture of crystal salt and water is called the soup of life. The German word sole came from the Latin word sol, which means the sun. So the brine solution is the fluid state of the sun or light energy
Ok – so let me get this straight : if you dislove salt in water you get a solution that they call ‘Sole’, this is derived from a word that means ‘sun’, and this means that I should buy your magic salt?’
What’s the Harm?
It’s easy to laugh at some of these completely stupid claims about salt, but it’s actually serious. Firstly ‘magic salt’ is expensive, Himalayian Mountain salt costs £7.99 a kg from Allhealth.co.uk which isn’t cheap for a product that is actually potentially harmful to your health. There is a considerable amount of evidence that reducing dietary salt has considerable health benefits, but all this nonsense is getting in the way of speading the word. I think if we actually all put a concerted effort to restricting the amount of salt we eat it could make a huge difference to public health. Most people would rather cut back on salt than stop smoking, drinking, or eating nice food. If you want to find out more about the real science I’d suggest starting with this review article: Links Between Dietary Salt Intake, Renal Salt Handling, Blood pressure, and Cardiovascular Diseases and this one is quite good as well: Salt and High Blood Pressure. Neither of them are behind a paywall.
I was going to write more, summerising the actual evidence between dietary salt and disease, but it’s 2am, and I’ve already written nearly 2000 words. If anyone is still reading, and is interested in the actual science then just leave a message and I’ll write that essay….
It Snowed. In case you haven’t noticed.
I’ve been trapped in a lovely but rather impractical Christmas card for 10 days . For 10 days I was completely unable to move my car. It was under 2 foot of snow and there was a mile long ice rink between me and the outside world. My wife who has a real sensible job was able to work from home., whilst the neighbour who has a 4×4 gave her a lift to the shop twice a week. I decided that getting snowed in was only for useless English People and tried to Carry On. On the first week I needed to get to the UK stroke forum where I was presenting a paper. After a 5 hour journey, which should have taken me an hour I arrived in Glasgow. I soon realised I wasn’t going to get home, so I sent texts to anyone I knew in Glasgow and managed to procure a sofa bed for the night.
The only way to get to work was to walk for 3 miles, get a bus which took an hour, and then walk another mile.It turned a 30 minute communte into a 2-3 hour drudge. People look at you oddly when you turn up into an office in full body waterproofs, including wellie boots, waterproof trousers, 2 coats, 3 pullovers, scarf gloves and hat.
I do a bit of clinical work and mostly research. The research was easy enough to do from home. I just got my computer set up so I could VPN into the office and got on with things. The clincial work was much more difficult. But fortunately I managed to get a room in the nurses home so I could get snowed in at work instead of at home. There are few things more depressing that being stuck in hospitial accomodation when you have a lovely warm house and wife just 10 miles away. Hospital accomodation is a single room, about 10 foot square with woodchip and an uncomfortable bed.
Being snowed in at work changed my mentallity about the 3 hour commute. It didn’t meant that I was struggling in to get to work, but actually that I was struggling to get home. And home was worth it. Though to be honest I only went home every other night, and not if I was working late.
Now there’s more forecast.
Where is Bed 13?
It took me a quite a while to realise that most hospital wards don’t have a bed 13. At first I assumed that Bed 13 must be a side room at the other end of the ward. Then gradually I noticed that on every single ward I’d worked on Bed 12 is next to Bed 14. With the exception of one ward where the sequence went 12, 12a, 14. When the ward was built one of the beds was labeled 13. Patients, scared and unwell, would refuse to get into it. Before long a paper sign, declaring ‘Bed 12 A’, was written with a marker pen and sellotaped over the offending number.
By coming into hospital you are putting your faith in medical science, so why hang on to some strange superstition? It seems that people like hanging on to irrationality. But then I started to think about the power of the placebo effect. If you believe that you are more likely to die because you are in bed 13, you might actually be more likely to die. We should harness the power of the placebo.
Maybe we should do a randomised controlled trial - take a number of similar wards, and remove Bed 13 from some of them but not others. Anyone fancy explaining this to the ethics committee?
I always knew that Automatic Defibrillators were rubbish, now I have Evidence.
I was really smug to read an article in JAMA telling me that automatic defibrillators don’t improve survival in hospitals. I should start of by saying that in public places automatic defibrillators save lives, but in hospitals they annoy the staff who are trying to get on with saving lives. I really detest automatic defibrillators in hospitals, I detest the way they tell you how to run an arrest using a really patronising American voice. I am a professional damit, I don’t need a machine, an annoying American machine, to tell me how to do my job. Isn’t it great when something that you really hate is proved to be ineffective? I makes you feel all warm and fluffy, knowing that your bizarre prejudice is actually based on reason. (My bizarre prejudice is actually based on the annoying accent, not reason, but we’ll skim over that.)
What is a defibrillator anyway?
A defibrillator is the machine that you use to shock someone’s heart back to life during a cardiac arrest. The one where you put the paddles on, shout ‘stand clear’ and push a button to dramatically shock your patient back to life. On TV they wake up, in real life they’re still dead. Usually. Occasionally they wake up, and that’s what makes it worth it.
When someone’s heart stops beating you can’t always try and shock it back to life. You have to look at the rhythm on the monitor and decide if you can shock it back to life. To be able to look at a rhythm and interpret it means that you need to be trained. Then you need to not forget your training in the panic of a cardiac arrest. This also makes it more difficult to put defibrillators in public places. You can train nearly anyone to do chest compressions but it’s much more difficult to train members of the public to interpret the rhythm on an cardiac monitor, and decide if it needs a shock. That’s why automatic defibrillators were invented. They talk you through the whole resuscitation in a nice calm voice. So it doesn’t matter if you panic and forget the details of CPR, you just follow the nice calm voice.
Why put Automatic Defibrillators in Hospitals.
There are plenty of reasons why it would seem like a good idea to put automatic defibrillators in hospitals. To run an effective cardiac arrest you need to not panic, and that means going to them regularly. There are some places in hospitals that just don’t see that many cardiac arrests, such as the outpatient eye clinic. However often the staff at the eye clinic go on the course they are not going to be practiced at managing a cardiac arrest. They are going to be able to do their best with chest compressions but its unlikely that they would be able to use a manual defibrillator. They would have to wait until the cardiac arrest team arrived before they could shock the patient.
It seems like a good idea to have an automatic one around the place. There’s one big disadvantage to automatic defibrillators: they interrupt chest compressions. You have to stop chest compressions whilst the defibrillator is deciding whether to shock or not, and it takes the machine ages, when it would only take an experienced person a few seconds. The advantage of an automatic defibrillator is that you can shock your patient sooner; you don’t need to wait for a cardiac arrest team to come running, possibly from the other side of the hospital.
But remember hospital patients are very different from people walking along a street. People in the street are generally healthy, and people in hospital are usually not healthy. If a person walking about the street collapses and their heart stops it’s probably because they’ve had a heart attack; if a hospital patient’s heart stops it is probably because they have died of whatever they are in hospital with. A heart attack is much much more likely to lead to a shockable rhythm than dying of pneumonia. In public places 41-71% of cardiac arrests are ‘shockable’ but in hospital only 20% of cardiac arrests have a shockable rhythm. The most important thing with a shockable rhythm is getting electricity to the heart as fast as possible, whilst buying time with chest compressions. If there’s a non-shockable rhythm the most important thing is to do chest compressions as well as you can without any interruptions.
Now an article in JAMA suggests that Automatic Defibrillators don’t improve survival at an in- hospital cardiac arrest. You can read the study here .The researchers looked at a database of all cardiac arrests in hundreds of participating hospitals in the US. All the hospitals took part in a national data gathering project to record details of all cardiac arrests. Some hospitals introduced automatic defibrillators sooner than other hospitals, so they compared them to each other.
Was this the best study design?
This was a retrospective study, looking backwards, a study looking forwards would have been a better way to assess the effect automatic defibrillators. But this was the most feasible way of assessing the evidence. They tried to correct for as many confounding factors as possible, but the hospitals with Automatic defibrillators may have been different from hospitals without them. It’s important that that used a primary endpoint of survival to hospital discharge, not just survival for a few hours.
What did the study show?
For patients who had shockable rhythms automatic defibrillators didn’t improve survival to hospital discharge, but they didn’t make it worse either. For patients who had unshockable rhythms automatic defibrillators actually made them less likely to go home from hospital alive.
Can I apply this study to my patients?
This was a study done in American hospitals, so it goes without saying that hospitals in the UK are slightly different. The skills of ward staff are likely to be different, and the patients will have a different mix of illnesses. The advantage of automatic defibrillators is that you can potentially get electricity to your patient quicker. The disadvantage is that the quality of the CPR isn’t that good. To apply this study to a British hospital you would have to assume that the level of training of the staff would be the same as an American hospital, the time that it would take for the arrest team to arrive would be the same, and the quality of the resuscitation would be similar.
What does this mean?
It seems that I was right! Automatic defibrillators are annoying and pointless. They are useful out of hospital but they don’t have a big role in hospitals. Though this was a retrospective American Study, so we still have a fer more questions to answer before we decide if they going to be useful in UK hospitals.
Chan, P., Krumholz, H., Spertus, J., Jones, P., Cram, P., Berg, R., Peberdy, M., Nadkarni, V., Mancini, M., Nallamothu, B., & , . (2010). Automated External Defibrillators and Survival After In-Hospital Cardiac Arrest JAMA: The Journal of the American Medical Association, 304 (19), 2129-2136 DOI: 10.1001/jama.2010.1576
So, should I believe this? The Bakewell Tart of Fact
‘Tai Chi is a good treatment for fibromyalgia”
“MMR causes Autism”
“Brain tumours are caused by mobile phones”
You only have to pick up a copy of any newspaper to see people making claims about medical treatments. The challenge is to decide if they’re true. The first thing most skeptics do is say ‘show me the evidence’, but nearly all claims will have some evidence to support them. There’s much more to evaluating a claim than just looking at the direct evidence for it. You have to think about how likely it is to be true.
| Good Evidence | Bad Evidence | |
|---|---|---|
| Plausible | Probably true | Nice idea, – now go and do a study |
| Implausible | Extraordinary claims require extraordinary evidence | Bullshit |
The first thing you have to ask is ‘Is this plausible? Based on what I already know about the universe is this likely to be true.’ If this claim is true will it violate all known laws of physics. will it mean overturning everything we’ve learnt from science up to now.’ . Then you look at the evidence presented for the claim, and evaluate the evidence in light of that.
Plausible idea + good evidence = Probably True
If the idea is plausible, matches with what science already knows about the way the world works, and there is good evidence to directly support the claim, it’s likely to be true. I may well start to act on it, I may start recommending it to my patients. I might be looking at a claim that a drug that prevents blood clotting will prevent strokes. The drug company has presented a randomised controlled trial, and have calculated a p value of 0.05, which means that there is a less than 1 in 20 chance that this was a fluke result and the drug is actually ineffective. A 19 out of 20 chance of being right isn’t bad. But I don’t just have this trial to rest my decision on. I have lots of other research as well, I have research that tells me that strokes are caused by blood clots, evidence that chemicals similar to this one break down blood clots, evidence that breaking down blood clots is generally good for similar situation in the heart. The clinical trial is the final cherry of evidence on an almond tart of knowledge, making it the Bakewell Tart of Fact.
Implausible Claim + Good Evidence = ‘Interesting, lets look more closely at that evidence’
Lets imagine that instead of the claim that a blood thinning drug treated stroke I am trying to evaluate a claim that crainal osteopathy can treat stroke. Now the Cherry isn’t sitting on a Bakewell Tart but instead appears to be floating in mid air. If this is true then it overturns everything I knew about how the brain works. I know that the brain is in the skull, floating in a bath of CSF, and the sort of massage that crainal osteopaths do can’t possible actually even touch the surface of the brain. I know that the stroke is caused by a blocked blood vessel or a bleeding blood vessel, but there is no way that crainal osteopathy can actually get near a blood vessel. Now lets say we’d got the same statistics, showing that there is a 1 in 20 chance that this result occured by chance. Based on my knowledge of how the world works, I think that there is a less than 1 in 20 chance that crainal osteopathy can treat stroke, so I want better evidence than this.
The evidence that crainal osteopathy can treat stroke had better be really good, because I need it to overcome all the other evidence about how the world works, and how the brain words. To quote the great Carl Sagan, ‘extraordinary claims require extraordinary evidence’
Of course just because we don’t know how a drug works doesn’t mean that we shouldn’t use it. We don’t really know how anaesthetics work: but it does mean that we need really good evidence that it does work before rolling it out.
Plausible Idea + Little Evidence = Hypothesis
If an idea seems plausible, and makes sense but there isn’t that much evidence to support it, then we call that a hypothesis. The next step is to look for evidence, you’d start off by looking for other experiments that tests the hypothesis. If no one has done an experience to test the hypothesis then you might do one yourself.
It may be that the experiment has already been done, and you have to accept that despite however much you like your hypothesis, and however much it makes sense to you, it simply isn’t true. If you want to be sure you could always repeat the experiment to check that it really was done correctly, and that the results are reproducible. But you might find it difficult getting funding, and you might find it difficult getting ethical approval if you want to do a test on human subjects. But you have the largest part of the Bakewell Tart and now you only need a cherry.
Implausible Claim + Bad Evidence = Bullshit
I don’t feel the need to do any experiment to find out that drinking water is an ineffective treatment for severe infections, or that cutting your leg off will not treat your migraine. You have neither cherry or almond flavoured tart, so whoever is trying to claim that you have a Bakewell Tart is wrong.
Electrolyte abnormalities, some basic theory
Dear House Plants…
Before calling the medical registrar about some electrolyte imbalances, consider the following.
Generally, these imbalances occur due to one of 3 things:
- Too much in
- Too much out
- Change in how much it’s diluted
So, for example, if you have been filling a 90 year old with 0.9% NaCl for 2 days, and have given him 8 litres of the stuff, but no KCl, I would generally expect for them to be hypernaturaemic, and hypokalaemic. Particularly if they have had a huge diuresis due to their obstructive uropathy being relieved by that catheter your reg put in!
They might be a bit dehydrated to, which would explain their recent drop off in urine output.
Try some sugar, instead of the salt, add some potassium, and speed up the drip!
Oh, and that CRP result you’ve been looking at? That means they’ve got an infection. Try treating it!
Here endeth the lesson.
Your friend
The on-call med. reg.
Your wife doesn’t want sex? Part 2 – how to f**k up some research (whilst not f**king your wife)
I was reading through the FDA deliberations on Flibanserin, the proposed new wonderdrug to treat ‘Hypoactive Sexual Desire Disorder’. How did the drug company end up trying to market it? There are two basic concepts that they either misunderstood or manipulated..
The Evils of Subgroup Analysis
Flibanserin was first developed as an antidepressent, and it reached stage 2 trials. Stage 2 trials are where it is given to someone who actually has the disease to see if it helps them get better. It doesn’t, the partipants were given a questionare so that they could rate the severity of their depressive symptoms, and one of the questions they were asked was ‘How strong is your sex drive?’. So far so normal. The overall score on the questionnaire wasn’t improved at all by the drug.
When you have a load of data, you need to work out if there’s any way this could have come about by chance. So you take all your data and do some sums.
How do you do these sums?
Imagine you have a coin and someone tells you that every time you toss you get a head, so you suspect that it has two heads. The easiest way to find out would to turn the coin over and see if it had two heads. But for some reason you can’t do that you. So you toss it five times, and you get 5 heads. There are two possible explanations here
1. Either this is a perfectly normal coin, and you have simply had a run of heads. This the least interesting hypothesis, so you call this the ‘null hypothesis’.
2. This is a two headed coin.
To decide this you have to do some sums, what are the chances of getting 5 heads in a row? If you had a coin and your chances of getting heads or tails was exactly 50:50, you could say that your odds of getting heads is 0.5, the odds of getting two heads in a row is 0.5 x 0.5, the odds of getting three heads in a role is 0.5 x 0.5 x 0.5. The odds of getting 5 heads in a row is 0.03125, or 1 in 32.
It’s generally accepted that if the odds of the results occurring by chance are less than 1 in 20 (0.05) then there might be something in your theory. This is called a P Value, usually you’ll see words such as p< 0.05 to indicate that a statistical test has shown that this particular result might be significant. If the p value is 0.05 then that means that there’s a 1 in 20 chance that this result occurred by chance.
So they had their drug, and it didn’t make people any less depressed. What now?
Well lets go back to your coin. Imagine for some reason that you didn’t get 5 heads, but really really really really want it to be a double headed coin. Perhaps you’ve told all your friends that it is a double headed coin and you don’t want to look stupid. But you toss it five times and it doesn’t give you 5 heads. Now you decide that perhaps what was wrong was the circumstances of the test, maybe if you did the test in a slightly different circumstances it would give you 5 heads. Perhaps all that was wrong was the alignment of the stars, or could it be the ley lines? So you go on a tour of your local ley lines and repeat you test at each of them. Eventually at a particularly auspicious combination of ley lines you do your test and find that you get 5 heads. Hallelujah! You now have a 2 headed coin, but only on junction 3 of the M8. Westbound. At dawn.
Hang on – though no one would deny that Deer Park Services, Livingstone is a very auspicious place – could their be another explanation? Remember those sums. There is a 1 in 32 chance of getting 5 heads every time you toss a normal coin 5 times. So if you tossed a normal 5 times in lots of different intersections of ley lines the chances are you would just strike lucy and get the right combination eventually.
Getting back to the drug
Imagine instead of a coin you have an anti depressant that doesn’t work. But you want it to work, though you can’t afford to repeat the trial 20 times until you get positive results. But instead you can try something else. You have given people a 20 item questionnaire on the different symptoms of depression, so you decide that though it seems it doesn’t affect the overall score it might have other helpful effects. For instance it might help people sleep, or help them worry less. So you do your stats for each different item on the questionnaire - and low and behold one turns out to be positive. But what you have done is pretty much the same as the person tossing a coin 5 times in lots of different places, you’ve effectively repeated the test until you get a positive result. This is called a subgroup analysis, and it’s a sign that the researchers are very keen to get some results, any results, and you should be sceptical of their result.
One of the questions that these patients were asked was about their sex drives. This seemed reasonable enough after all a lack of interest in sex is one of the symptoms of depression. And when they did the subgroup analysis they found that women on the active drug were more likely to have a better sex life than those on the placebo drug.
This seemed to be a reasonable hypotheisis so they did the right thing and did a larger trial, which they claimed to be positive. Which brings me to another way to f**k up research:
Statistical Significance is not the Same as Clinical Significance
The FDA judged that although the result of the trial was statistically significant it wasn’t clinically significant. To see what that means lets look at another analogy. Say you have a drug that you think might reduce blood pressure, you do a big trial and find that it reduced blood pressure by 1 mm Hg, it brings blood pressure down from 185/89 to 184/88. You have tested lots of people so you know that it has this effect in everyone. But of course bringing your blood pressure down by such a small amount wouldn’t make a jot of difference to your health, it won’t make a difference to your chances of having a stroke or a heart attack. It’s just pointless. But the test showed that it was statistically significant.
Though there was a slight increase in the average score on a sexual satisfaction questions the FDA was not convinced that it was enough of an increase to actually make a difference to women’s lives. For instance it may mean that women score they’re sex lives as ’2/5′ instead of ’1/5′, so a bit better but not great.
So there two are – two ways of messing up research sub group analysis, and statistically significant, clinically insignificant end points. Keep a look out for them when you’re reading the literature.
Your wife doesn’t want sex? She’s broken, take her to the Doctor
One of the things that annoy me most about Big Pharma is the fact that they sometimes create a pill and then try and create a disease to follow it. A lot of people assume that if you are anti alt med you automatically think that all Big Pharma is wonderful. Er. No. Annoying drug reps is one of my favourite hobbies, it’s like badger baiting but legal, and the badger gives you sandwiches and pens. Anyway I was flicking through my huge pile of BMJ back issues when I came across an article on low sexual disease in women, where Ray Moynihan has written an article arguing that drug companies are attempting to create a disease so that their drugs can be used to cure it.
Take a look at the website ‘sex brain body’. Nice isn’t it? Friendly, full of happy healthy women having happy healthy sex lives. If they don’t have healthy sex lives they know they have a problem and they get it fixed. Because women who don’t want to have sex have a problem with the brain. Obviously. There aren’t any other reasons why women might have low sexual disease. No. Nothing to do with the relationship changing as they’ve been together longer. Or her husband loosing interest, or having children, or just a change in the relationship as things change. It shows you lots of tools, quizes that help you discuss sexual desire problems with your partner, fair enough, and your health care provider. Less fair, there really is less that they can actually do about it.
What it doesn’t show you is that the website was funded by Boehringer Ingelheim, who were due to launch their drug Flibanserin in 2010. First they tried to use it to treat depression, but it didn’t work very well, but one of the questions used to assess depression is ‘how is your sex drive’, and it seemed to improve sex drive. So far so good. The female viagra! So they prepared to use the drug to treat Hypoactive Sexual Desire ‘Disorder’ in women. They did some trials to assess safety and effectiveness. There as a small problem, most women don’t discuss their sexual desire with their GP, they didn’t see it as a medical problem. So first they had to create a way of diagnosing it, a screening tool, then they had to tell women to use it to see if they had a problem. So far, so good. When the drug launched their would be legions of women all ready to tell their doctors that they wanted it. But there was a problem. Isn’t there always a problem? The FDA wouldn’t play. They read the studies and found a small problem. It wasn’t proven to work that well. You can read their deliberations here . I have to admit I was snickering as I read this. What a shame it’s all fallen apart! Poor drug company. What about the women who read the website and believed that they had something wrong with them? Who believed that they had a physical problem that could be fixed by a drug. What should they do? Forget about it? Try magic pixie dust?
That said it’s well known that certain medical conditions affect men’s ability to have erections, so logically it should follow that some medical conditions would prevent women having satisfactory sexual pleasure. But if you’re going to treat it you’d need to spend some time working out the true cause of the problem, which might not be related to a physical condition at all. In fact you’re going to have to find out what on earth is going on, treat the route cause, not the symptom.
Mind you sometimes I have to admit that some created diseases actually do cause suffering. Osteoporosis has all the hallmarks of a created disease it describes the thinning of the bones as people get older. Every one’s bones get thinner as they get older, so by trying to stop them thinning you are altering the natural process of ageing. But by treating osteoporosis you prevent hip fracture and in elderly people hip fractures lead to death. Death is bad. SO that’s worth treating. But only if you’ve proved that the treatment benefits the patient and doesn’t just improve the meaningless measurement of bone density on a scan. I want proof that it prevents fractures, and proof that it prevents deaths.
There are so many real diseases causing real suffering we really don’t need to go creating more of them. I don’t see Africans walking 30 miles across the bush because they are bothered by restless leg syndrome, or by hypoactive sexual desire. They need real medicine for their HIV and malaria.