Hi everyone. I'm Helen Ashdown, so thank you very much for staying on into the evening to listen to me.
I'm aware that you've had a long day, so I'm very much going to be talking about the kind of the lighter side of diagnostic studies.
You may think what could possibly be the link between Breathalysers babies and bombs,
but as you probably guessed, it's that the link between them is the study methodology and the diagnostic studies.
And what I really want to talk about is my experience.
So happened that I ended up doing a few diagnostic studies, partly because I really enjoy them and I think they're really they're really good fun.
And so I wanted to share with you the kind of the fun side of that and really convince you that diagnostic studies are great.
And I think they're well, hopefully in that space of me saying that,
I really I really do think that it's a really simple, straightforward sort of study methodology,
which is, you know, once you put your head around, there is really you know,
there's lots of studies that can be answered using diagnostic test accuracy methodology.
So what am I going to talk about?
Does these three studies that I've been involved in breathalysers immunisation history and speed bumps and appendicitis.
Now, immunisation is obviously really, really important, but it's just slightly less exciting I think, than breathalysers and speed bumps.
So I'm actually probably get to talk about that for a few minutes and mainly concentrate
on what I've done with the Breathalyser Study and the Speed Bumps of Appendicitis study.
And what I'm going to talk about is kind of a how the study was designed in relation to the designing,
the designing the research question and formulating that and how we designed
the study to answer the question with the kind of the bumps along the way.
So things that things that came up which were unexpected or interesting, and then to also focus on the kind of the communicating the findings aspect.
So particularly with breathalysers and speed bumps, they've, they've had quite a bit of media attention.
And so I wanted to concentrate on the the sort of how you explain diagnostic studies to the public and how how to kind of sell diagnostic studies,
because it's not necessarily something which is easily understandable by by non, you know, people that don't don't understand the methods.
And so you can see here, this is a video and you have to also I'll talk about how these how these came about.
But first, it's come out a little bit small.
So I don't know if this will be possible, but I was going to test your Oxford knowledge and ask you, first of all, which pub is that?
Does anybody know where say.
No, but I think that's a good guess. Canal in the background. It's the Jolly Bateman and Swamp.
There we go. And where abouts is that? Now it is.
Say something. Yay! Yay! Well done.
So, yeah, so how these two pictures came out, how they came about and the sort of the stories behind them.
So I'm sure this is really you will have done this today,
but I just wanted to put it there in case as anybody that hasn't been on the course and wanted a bit of background.
So instead of thinking about this typical peak out with diagnostic studies, I always think of this instead as a sort of pit.
I hope I auto thinking about the patients or participants.
The index test, the reference test, and then what the target condition is.
And then putting them together to give us a sensitivity, specificity, positive, a negative predictive value and likelihood ratios.
Hopefully that should make sense to everybody. You probably all know this already,
but basically in the UK there's an immunisation schedule where babies have have immunisations
and it's the same in countries around the world but kind of differs between different countries.
And this set points when children have it and they get a letter in the post inviting them and then they get
follow up reminders and they also and it all gets recorded in this child health record that all children have.
But there are some children who don't have the immunisations up to date or even with the immunisations and the reasons for that.
You know, there's many reasons for that. It may be that the parents actively decide that they don't want their child vaccinated,
or it may be that they or it may be that there's just reasons, you know,
they've forgotten or the letters aren't getting through or they don't have the time to take the children to the doctor,
you know, all kinds of reasons. But when children go to hospital, when they go to the emergency department, when they're not planning to,
you know, when they're not planning to do so, obviously an unplanned admission.
It's a good opportunity to ask parents about it.
And that's both so that you could potentially identify if the child might have one of these diseases causing that presentation.
You know, obviously, the chances of measles is higher if you haven't been vaccinated against it.
But also as an opportunity to kind of give education about the importance of
immunisation and even give the immunisation while the child is in hospital as well.
So it's important in those respects. And what we wanted to find out was whether history taking, say,
whether the process of the doctor asking at the initial clerking of the patient, is your child up to date with their immunisations.
How accurate that was for telling whether the child is is actually up to date.
So what we do is formulating the research question saying how good is it clocking at picking up children who are overdue with their immunisations?
So we looked at children six months to six years presenting to the emergency department, looked at immunisation history.
So for that, we went through the emergency department cast cards, which at that stage everything was done written,
whereas now it's electronic and where people had written kind of up to date IM's or whether there was any kind of mention of it.
And then combined compared that with a central primary care immunisations record database,
which is a central local database where this sort of information is held and looked at to whether they were overdue with their immunisations or not.
And what were our findings? So 76%.
So about three quarters had had an immunisation history documented and that was lowest for the surgical and mine injury presentations.
And also the older the child was 5% recorded as incomplete on the history.
And then when we compare that to the primary care database, it was slightly higher.
So 7% and we include excluded some children because of the if they were only just
overdue or if they'd moved from out of area or if they didn't have an NHS number.
So there were various reasons that that those numbers have sort of decreased down.
And what we find so we found that the sensitivity of this immunisation history
for picking up children who were actually overdue was eight was less than half.
So it's only about 40% who picked up using the methods. But if they are picked up, it's a relatively specific method.
So our conclusions, less than half of those overdue, are picked up by history.
Taking the highest sensitivity was in the younger age groups,
which kind of makes sense in that it's kind of closer to when parents are when the child is actually had that immunisations.
But there is a limitation of this in that the primary care database may overestimate those who are overdue, for example, if stuff hasn't been updated.
We did get that the the local PC, the Primary Care Health Trust,
people who run the database actually very kindly phoned up every GP practice of the people we identified
as overdue to check that it matched the GP records and say we're relatively confident that it's accurate.
But at the same time it's possible that those original GP records in themselves weren't weren't necessarily up to date.
Moving on, speed bumps. So since I started doing this project, I've been collecting pictures of speed bumps.
And this was from our holiday in.
Western Canada. So this is on Vancouver Island in British Columbia.
Really good speed. But my husband's absolutely sick of me going places and saying, say, oh,
there's a really good speedbump, please, can we get down this road and take a picture of it? And this was very recently.
So this is hot off the press. So the first people see this particular speed bump.
Anybody, any guests for it is islands in the background.
It's the west coast of Scotland, and that's the show of egg and that's the island of Rum.
And this was, I think, news day or something. Anyway, good.
Particularly good speedbump signs.
These slides are taken from a presentation I gave M.I.T. a few months ago, and I'll come into that onto the reasons for why.
But one of the things throughout is that lots of people have asked me to define what is a speedbump,
which I find a bit strange, having grown up with speed bumps. But it is a rich set at intervals in a road surface to control the speed of vehicles.
And they are also called sleeping policeman, which is the British equivalent,
which the Americans all found very funny when we were over there because of well,
a few of them had come across the Thames sleeping policeman before, but not not many of them.
And the reason behind this study was,
say this started when I was a surgical house officer and we had lots of people coming in with suspected appendicitis.
Now, just to give you a little bit of background of appendicitis, you know, for the non medics, you know, that, you know,
appendicitis can be really classical and it's obvious even to, you know,
the person next door or your grandmother is appendicitis, but often it is not quite so clear cut.
So you use it. The doctors use a combination of symptoms and signs.
So things like whether the pain moves, whether the patient has nausea and vomiting to try and work out if it is appendicitis.
But it's good to pick it up early because if you miss it, then it can get more.
It can get more serious and can it can cause sort of severe sepsis and even death.
And the definitive treatment is is to remove the appendix surgically.
But that's something which actually more recently is a little bit more questionable
and certainly mild cases are now sometimes treated with antibiotics instead.
So what we wanted to the reason this kind of came back was that we've noticed that
quite a few patients in the hospital would say that the journey had been terrible.
And I worked with one of the surgeons who said, oh, speed bumps. Absolutely.
You know, if the patient says they've had pain on going over speed bumps,
they absolutely must have they straight to theatre, they must have appendicitis.
Let's not worry about any blood tests or scans.
And obviously they were joking, but they'd noticed that there was this strong association and we thought actually that would be really easy to test.
You know, it would be quite easy study to do. So what we did, we looked at patients who'd been referred with possible appendicitis,
looked at the index test as pain over speed bumps, appendicitis on histology as our reference standard,
say what it looks like under the microscope and if it's showing signs of being
appendicitis and then obviously the target condition being acute appendicitis.
And we did this at Stoke Mandeville, which is famed for its link with spinal injuries and and was the place that the first Paralympic Games were held.
The reason that we well, it was a good place to do it because Aylesbury is a hospital that's got quite a few speed bumps and you know,
that's a good reason to do a study, obviously.
And what we did was we looked to patients who'd been referred with possible appendicitis by either the emergency department or via their GP.
We gave them a questionnaire when they were first admitted to hospital.
So before they'd had any, you know, before they'd had any treatment.
And this questionnaire kind of asked about the journey to hospital and whether they'd travelled over speed bumps and if they had,
whether it made the pain worse or better. And then we got their permission to follow them through and sort of see what happened in relation
to whether they went on to have appendicitis or not and those who were discharged home,
we telephoned them a month later just to check that they hadn't been admitted elsewhere,
that they hadn't had a you know, they hadn't been diagnosed subsequently with appendicitis.
And yeah, so we followed them very happily. Nobody, happily, nobody died in our study, which was very good.
And we looked at the appendicitis histology to see,
to see that and that was blindly assessed by somebody who hadn't been exposed to the who hadn't seen what,
whether the patient had had pain, O2 speed bump.
So it was an independent assessor of the kind of interpretation of the histology results and the pathology department.
The hospital had no idea that we were doing the study, so in that respect it was quite good that nobody knew it was going on.
It was published in the Christmas BMJ in 2012 and it had a particularly good cover image.
So I put this on, it was the Sgt Pepper staff cover, which I think is great.
These are the results. But I've actually because these are the slides that I used I thought would actually be interesting to
explain the results in the kind of the way that I did it to the public audience a few months ago.
So this is from the original paper and I think later this week, I don't know with the latest tweet,
you're going to be looking at the speed of those papers anyway. I think Richard talks about it.
And so 101 patients were recruited in the study, 64 who travelled over speed bumps were included in the analysis.
So we excluded those that said they hadn't been over any speed bumps.
54 of those who travelled to speed bumps had worsened pain and we called those speed bump positive 34 patients in total.
All have confirmed appendicitis and three of them had pain over speed bumps.
And that gives a 97% sensitivity.
So only one person didn't have pain over speed bumps.
And that is a better sensitivity than other symptoms and signs of appendicitis.
So it scored better than migratory pain, nausea and vomiting, rebound tenderness.
And having such a high sensitivity means that it's a really good rule out test, as you know.
And so it's really good for saying actually, it's really unlikely that you have appendicitis.
However, lots of those who were speedbump positive didn't have appendicitis.
So just because you have pain over speed bumps doesn't mean that you necessarily have appendicitis.
And that was the worst thing about the media associated with this, that loads of newspapers said, do you get pain when you go for speed bumps?
If so, go to a hospital, you might have appendicitis.
I was thinking, no, they want me responsible for these people going to the hospital on account of us, on account of our study.
And yeah, as I say, there was lots of media attention at the time,
but what I really wasn't expecting was to get a phone call last Easter from a guy in in London,
a professor, saying, oh, I think I think you might want to give me a call.
I'm at home painting. This is my home phone number. I looked him up and he seemed like he was a proper, proper professor.
And and I kind of thought, well, what have I got to lose by giving him a giving him a call?
Even though I was away on holiday in Scotland at the time and I phoned him up and he said, Have you heard of the IG Nobel Prizes?
And I said, No, no, never heard. And he said, Oh, you've won one.
And obviously it was slightly lost on me, the significance of this, having never heard of them.
But I was saying with a group of friends who who had kind of like got off the phone and then immediately said, What are you running on prize?
That's amazing. I think in non-medical subjects, they're very highly regarded and they're seen as the sort of greatest accolade that you
can get in your scientific career if you're not going to win a proper Nobel Prize.
So what they're sold, as is the IG Nobel Prize, is on the research that makes that first make people laugh and then make them then make them think.
And Nature Magazine call them calls it the True Nature Journal, calls it the highlight of the scientific calendar.
And it really was you know, they were awarded at Harvard and they really make a huge, huge thing over the over this out.
You know, there was just a huge amount of media attention. There's lots of people to travel from all over the world.
I was interviewed by of Japanese TV stations, Russian TV stations, and I never even heard of these awards before.
People just really, really excited that I was one of the winners of these really most coveted prizes.
But the ceremony is absolutely mad. I've never had such a mad evening in my life.
It's got paper aeroplane fights and this guy stands on the stage as a kind of target and people throw paper aeroplanes at him.
And as I was sitting directly behind him,
you're just in the sea of paper aeroplanes and it's just a kind of public lecture thing as there was a guy swallowing,
swallowing a sword and that so but it was in a sort of scientific way.
I can't quite remember the details, but anyway,
and then you win these prizes and they put a lot of effort into the prizes and I brought my prize along to show you because I would say I'm very,
very proud of this. This is my IG Nobel Prize.
And what's what's particularly great about this is that bringing it back from the States?
I came I got my bags out of the, you know,
of the baggage collection thing at the end and saw that my bag had been opened and my padlock had been cut free.
And afterwards I thought actually that was kind of obvious that that was going to happen
because it looks like this big sort of thing with all these wires coming out of it.
And I thought, no, the people opened it and tried to find out what it was.
Must have been it must have been really, quite, really, quite surprised.
Probably had to go, what is it? What is an IG Nobel Prize? But I wanted to show you two bits from the ceremony, like, thank you.
As you know, we used to have a problem at this ceremony.
Many of these speakers would exceed their allotted amount of time.
Here's how we now solve that problem. Please welcome the charming, the delightful, the ever so cute.
Miss Sweetie. Who? The swimming pool is eight years old.
Mr. Sweeting, how would you demonstrate what you will do when somebody exceeds his or her allotted time?
Please stop. Oh, please stop.
Oh! Oh! Oh!
Oh! Thank you. I'm a sweetie.
Thank you. Miss me? Thank you.
So. So the ceremony is just full. That's just one example of what is a completely crazy ceremony.
And remind me quite a lot of kind of Monty Python style style things.
But I just wanted to end by showing you our acceptance speeches. Again, something I'm very proud of.
My friend from Edinburgh actually wrote it for us because it was very difficult to try and think,
how am I going to summarise my research to a non-medical audience in just one minute?
So this is this is what we did, and we were actually allowed a little bit of time afterwards to do a demonstration as well.
But it was really good because then the demonstration really caught the press's attention.
And I never thought when I started my medical career and started an interest in kind of diagnostic
studies that it would lead me to being on stage at the University of Harvard dressed as a speed bump.
But it really was my proudest moment. This was the this was the win a date with a Nobel laureate competition that they had beforehand.
And they were real Nobel laureates that give out the prizes. Diagnostic Medicine Prize.
The IG Nobel Prize for Diagnostic Medicine is awarded to Diyala, Kareem of Canada and the UK after the harm done to New Zealand, the UK and the U.S.
Nigel D'Souza. That's me. If you missed me in the middle of it, the speed bump happened.
South Africa, the U.S. and the U.K. Andrew Wall of China and the U.K.
Abdelkader Aloni of Syria and the U.K. and Helen Ashdown, Richard J.
Stephens and Simon Krakower of the UK for determining that acute appendicitis can be accurately
diagnosed for the amount of pain evidence when the patient is driven over speed bumps.
We tried to give our speech too quickly. We're also awarded $10 trillion.
I'll tell you better than this. This is less how this day.
But first of all, we'd like to say we never achieved this perk without the other group as well.
And so, you know what else is missed? We've got both sides, you know.
Our moms and dads. Let's not forget. I hope they're watching on the net and all I can yell at.
Answer J. Oh, my God.
Oh, God. That's one of the professors of our department.
He's. Just what the [INAUDIBLE] is wrong with him?
Please cut off the grid. If it's a hostile.
Brain disease, appendicitis. Could it be?
It could be that. Now, let me see. But how would I have to see to you an ultrasound or an X-ray?
Man, just read our paper. Then you'll know the speed bumps all the way to show.
Just so I can quickly offer help. You know the paper.
They can jump. Appendix cases that we sent was sensitive at 97%.
It really is the simplest test. Their specificity is not best.
So see diagnostic test accuracy to a wide audience, he states.
Oh, my God. He's got appendicitis.
He's not. Not normally like that.
I'm sure we have a little demonstration. Is that correct?
We have a demonstration. This was the moment I regretted wearing high heels.
But. And you'll know Antony's appendix there was made out of tights.
I happened to have a safety pin to. And then some lucky person in the audience, Joe, got got Anthony's appendix, another one.
So, yeah, it was completely, completely mad. The $10 trillion are actually Zimbabwean dollars, which have a value of about 20 PPI or something.
So sadly so I have been awarded $10 trillion.
But that, yeah, sadly is not worth very much.
I think that's all I wanted to say pretty much, other than I mean,
we got lots of media stuff around the time and they loved all the pictures from it and it was really nice.
It was really nice because it gave an opportunity to talk about kind of how much fun
diagnostic accuracy research is and also kind of public engagement in science and things.
And that's my final slide. I always like to put a picture of my cats in presentations.
This is Agnes and Pippa, but they really like diagnostic accuracy studies, too.
So, yes, that's all I want to say. Thank you very much.