Clinical trials are in the public eye once again, and Vitamin D for COVID is especially topical right now. Like everything in healthcare, the trials are complex, so here’s an explainer on them. These points are most important for doctors but relevant to us all. 1/15
One particular trial provoked debate this week. Enthusiasts insist it proves the role of Vitamin D in treating COVID but experts highlight numerous problems with how the research was done. These limitations mean the research should not, on its own, change patient care… 2/15
…because we need to understand the strengths and weaknesses of a trial to safely use the results to shape patient care. When non-experts get involved we have problems. Some doctors make these mistakes too I’m afraid. 3/15
The best evidence comes from randomised trials where we allocate patients to treatment A or B at random. This avoids doctors guessing about who may benefit the most and who may get the worst side-effects. Our guessing often results in very misleading data! 4/15
Small (10s-100s) ‘efficacy’ trials test treatments in ideal circumstances. But real-world healthcare is never ideal so we also need large (100s-1000s) ‘effectiveness’ trials to allow for this. Efficacy trials answer ‘can it work?' Effectiveness trials answer ‘does it work?’ 5/15
Efficacy trials limit which patients take the treatment, and control how its delivered. Effectiveness trials are more like normal healthcare. Treatments are simplified to make them easy to deliver correctly, and given to any patient who may benefit, not just the best fit. 6/15
It's common to find that treatments show promise in small efficacy trials but don’t work well enough in large effectiveness trials. This doesn’t necessarily mean they don’t work at all rather that the real-world benefits may be marginal or too small to justify the treatment. 7/15
We might think that even a small benefit is worth having, but this ignores the downsides that every treatment has. Whether it’s treatment harm (every drug has side-effects) or just making patient care more complicated, the downsides of a treatment often outweigh the upsides. 8/15
In my early days as an ICU doctor, we tried all sorts of treatments, thinking even a small benefit was worth taking. But one by one we found many of our treatments caused harm which we couldn’t see. We know this because we did large effectiveness trials. 9/15
When there isn’t a clinical trial to tell us how to use a treatment, we study it in routine patient care to see how well it works. But these ‘observational’ studies are often misleading because the results are strongly influenced by what doctors expect to happen. 10/15
Sometimes doctors argue about new treatments. One group may want every patient to be given the treatment without delay while others first want to see evidence from clinical trials. The pandemic provides many examples of why clinical trials are needed. 11/15
Hydroxychloroquine, azithromycin, lopinavir–ritonavir and convalescent plasma are all examples of treatments that many doctors wanted to use in every patient. Clinical effectiveness trials showed that none of them helped. A treatment which does not work, can only do harm. 12/15
We also see some treatments which have only modest benefit. So we use them but only in carefully selected patients. The anti-viral drug Remdesivir is a good example. Some think the anti-inflammatory drug Tocilizumab should be in this category too. 13/15
Then there are treatments which do work. We wouldn’t be using dexamethasone in every patient if it wasn’t for strong evidence from a large clinical trial. Some doctors (like me) were worried about side-effects. Whatever the answer, clinical trials improve patient care. 14/15
The pandemic has put the value of large clinical effectiveness trials beyond doubt. The culture of medicine must change to make them quicker and easier to deliver. Through @NIHRresearch, the UK leads the world in this type of research, but we could still be so much better. 15/15
PS In the case of Vitamin D, the evidence isn't there yet to implement a policy where we prescribe it to everyone. We only have data from small trials and some of these have problems which make them hard to interpret. But large effectiveness trials are under way.

• • •

Missing some Tweet in this thread? You can try to force a refresh
 

Keep Current with Rupert Pearse

Rupert Pearse Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!

PDF

Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @rupert_pearse

13 Feb
New coronavirus infections are decreasing and 14 million people in the UK have received one vaccine dose. But the sitrep is that hospitals are still caring for 24,352 COVID patients – more than at the peak of the first wave. NHS staff cannot rest yet. 1/8 bbc.co.uk/news/health-56…
Despite the absurd claims of COVID sceptics, we have seen a huge number of excess deaths in the past 12 months, and well above the five-year average mortality rate. COVID remains the leading cause of death right now – many amongst working age people. 2/8
The pressure on the NHS remains extremely high and will be for months to come. This by @Zudin_P and @stevemathieu75 for @ICS_updates describing the vast effort needed to create extra Intensive Care beds across the UK. We still have more ICU patients than the first wave. 3/8
Read 8 tweets
30 Jan
Sitrep: situation report. This is what we call our daily briefings right now. Here’s mine. We are now fairly confident we have reached the high water-mark for the second wave of COVID-19 NHS hospital admissions across the UK. Good news but.... 1/10
....we still have nearly 40,000 patients in hospitals with COVID-19. Despite huge increases in staffing, we are very short-handed. In many hospitals, admissions have stabilised but not all. Some differences across the UK. Things still getting worse in the Midlands and North. 2/10
4000 of these patients (10%) need intensive care. This is huge: in January 2020 the UK had only 4100 adult ‘critical care’ beds including both ‘intensive care’ ventilated beds for the sickest patients and 'high dependency' beds for less sick patients. 3/10
kingsfund.org.uk/publications/c…
Read 10 tweets
23 Jan
Oxygen supply in hospitals is getting a lot of media coverage. Some hospitals are using five times more oxygen than usual triggering low pressure alarms. Media reporting oxygen supplies ‘running out’ and ‘not enough to go round’. The problem is not quite what it sounds… 1/12
We don't usually think about oxygen supply. It isn't something we notice until the oxygen pressure alarms go off. That used to be rare. The unfamiliar and emotive problem can seem frightening for NHS staff and public alike. This from @ChrisCEOHopson 2/12

Oxygen supplies don’t run out like an electricity power cut. Instead the pressure drops like it can with the hot water system in your home. Your shower doesn’t run dry but the water pressure is not what you need. You may need to turn some other taps off to solve this. 3/12
Read 12 tweets
20 Jan
A bit of controversy at the moment about medical students redeploying in Healthcare Assistant (HCA) roles. Some unfortunate language which I’m sure is regretted. I’m very involved in the @QMULBartsTheLon @QMUL med student redeployment and would like to point a few things out. 1/8
In the first wave (March), med student studies were suspended. Ours had just finished final exams and *volunteered* to join us to support patient care. They did not expect to get paid. They were incredibly professional and made me very proud to be a @QMUL prof. 2/8
In the second wave (January) our students’ studies have NOT been suspended. We (@QMULBartsTheLon) have *sent* them to help. While many would choose this, not all would. Our final years have major exams looming and must also complete educational log books, attend teaching etc. 3/8
Read 8 tweets
19 Jan
Optimistic news: National data on new coronavirus infections data do now show we have passed the peak. Good news but really this is just the end of the beginning for the NHS response. 1/7 https://coronavirus.data.gov.uk/
Firstly, the national data hide regional differences. New infections are still increasing in many parts of the UK. NHS hospitals in different areas will need to support each other for some time to come. 2/7
This map illustrates this much more clearly. Many areas of the country still very badly affected by new infections. This affects NHS healthcare in pretty much every part of the UK. 3/7 https://coronavirus.data.gov.uk/
Read 7 tweets
17 Jan
What reaching the peak means for the NHS: We're increasingly confident we have hit *a* peak and hopefully *the* peak of the second wave of coronavirus infections. Hospital admissions lag behind and will carry on rising for another week or so, but this is still a key moment… 1/10 Photo @jometsonscott
I have talked before about how and why the healthcare the NHS provides right now is simply not as good as usual. We have protected emergency care but routine care for cancer, cardiac disease and so many other illnesses has been badly affected. Especially surgical treatments. 2/10
The surge in COVID patient admissions has a huge impact on other parts of the NHS. We see this pattern often in the winter flu season but it is far worse right now. The shortage of normal hospital beds and ICU beds makes in-patient work very difficult. 3/10
Read 10 tweets

Did Thread Reader help you today?

Support us! We are indie developers!


This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!