9 ms·
Parachute use to prevent death and major trauma when jumping from aircraft
- nabla9 8y agoRemember to reard the linked editorial for context: https://blogs.bmj.com/bmj/2018/12/13/we-jumped-from-planes-without-parachutes-and-lived-to-tell-the-tale/ https://blogs.bmj.com/bmj/2018/12/13/we-jumped-from-planes-w... > We conducted the PARACHUTE trial to illustrate the perils of interpreting trials outside of context. When strong beliefs about the standard of care exist in the community, often only low risk patients are enrolled in a trial, which can unsalvageably bias the results, akin to jumping from an aircraft without a parachute. Assuming that the findings of such a trial are generalisable to the broader population may produce disastrous consequences. >Before you jump to the conclusion that we’re suggesting we jettison RCTs from clinical research, let us clarify that that is not our intention. In an ideal world, new interventions would always be carefully evaluated through rigorous RCTs before widespread adoption. But when pre-existing convictions about an untested intervention affect the population enrolled, even a well conducted RCT can provide misleading results. Without careful attention to context, extrapolating findings from such an RCT to the patient in front of us may be, well, a leap too far.
- joker3 8y agoIt's also essential to read the first cited article (https://www.bmj.com/content/327/7429/1459?ijkey=3b8c1a70a8d21a7e0a17d524eb5376914857d03a&keytype2=tf_ipsecsha https://www.bmj.com/content/327/7429/1459?ijkey=3b8c1a70a8d2...) which very much inspired this paper and is also quite a bit funnier.
- byset 8y agoIt's like when someone says something funny, then another person follows up with a witticism that basically repeats the same joke... Like someone makes an inspired pun and some dude immediately exclaims "LITERALLY!"
- ikeboy 8y agoThey did an actual trial here though
- excalibur 8y agoAlso, the one with the trial was just published, while the funny one is from 2003. Maybe this is immediate in sea turtle years?
- codeulike 8y agoThe point being made by this new paper is actually substantially different to the original 2003 one
- marcosdumay 8y ago$37 for 1 day access to download the paper. If that's not part of the satire, I don't know what it is.
- nkurz 8y agoThat might be the suggested amount, and it is a great paper, but I think you are allowed to donate less if you choose: http://sci-hub.tw/10.1136/bmj.327.7429.1459 http://sci-hub.tw/10.1136/bmj.327.7429.1459
- deleted 8y ago[deleted]
- superkuh 8y agoThankfully at least bmj still has a real website. Most of the elsevier journals have moved on to a 'web app' design for journal articles and IEEEXplore has as well. These load and display absolutely no article information until you successfully run all of their third party code (only works in latest Chrome and FF). That means you can't even get the DOI from the page for sci-hub. All you get is the crappy little 'loading' spinners.
- asdofindia 8y agoYou will benefit from http://unpaywall.org/ http://unpaywall.org/
- conistonwater 8y ago> The relevance to parachute use is that individuals jumping from aircraft without the help of a parachute are likely to have a high prevalence of pre-existing psychiatric morbidity. Individuals who use parachutes are likely to have less psychiatric morbidity and may also differ in key demographic factors, such as income and cigarette use. It follows, therefore, that the apparent protective effect of parachutes may be merely an example of the “healthy cohort” effect.
- simonh 8y ago>We think that everyone might benefit if the most radical protagonists of evidence based medicine organised and participated in a double blind, randomised, placebo controlled, crossover trial of the parachute. Classic.
- scythe 8y ago>Compared with individuals screened but not enrolled, participants included in the study were on aircraft at significantly lower altitude (mean of 0.6 m for participants v mean of 9146 m for non-participants; P<0.001) and lower velocity (mean of 0 km/h v mean of 800 km/h; P<0.001). This is an amusing didactic example of how the "fine print" can invalidate a study's conclusion.
- kalmi10 8y agoPlease fix the title. It's misleading. The linked article in no way claims that "Parachutes prevent death when jumping from aircraft".
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- nkurz 8y agoWell, maybe it does if you correct for the obvious errors in the statistical analysis. How did this get through peer review? I was particularly bothered by this sentence: "A P value greater than 0.05 was statistically significant." Presumably they meant "less than", but it's hard to trust any of their conclusions with such sloppy attention to detail.
- yakshaving_jgt 8y agoGiven that it says "randomised trial", it's implied that there would be a control group — a group of people who are sent to die for the sake of an experiment. Given that nobody would ever do this, it's quite obvious that there's some tongue-in-cheek angle to the story. It isn't misleading if you can read between the lines.
- ikeboy 8y agoThe finding was that parachutes have no effect on deaths. Title is the exact opposite of the finding.
- nkurz 8y agoTo the contrary, I think it might be you who is jumping to unfounded conclusions. Contrast the current title "Parachutes prevent death when jumping from aircraft: randomized controlled trial" with the first line of from the Conclusion of the paper: "Parachute use did not reduce death or major traumatic injury when jumping from aircraft in the first randomized evaluation of this intervention".
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- vamos_davai 8y agoWould you indicate this is a satirical article? Half the time I was looking for jump height or understanding if adding parachutes to commercial aircraft that suddenly experienced breakage such as a missile would improve passenger survival.
- oh_sigh 8y agoI've done over 900 jumps so I can fill you in, no references ATM because I'm on my phone. If you jump with a parachute, you will see chance of death go from 0% at zero feet, to approximately 100% at 35 feet. From there, it will remain near 100% until you reach about 600 feet, which is about the minimum distance it takes a parachute to open. Above 1000 feet and chance of death floors out near 0%
- b_tterc_p 8y agoWill jumping from high enough without a parachute ever decrease the odds of death than they the odds of death at a lower altitude?
- yakshaving_jgt 8y agoNot for humans. You're thinking of cats. https://en.wikipedia.org/wiki/High-rise_syndrome https://en.wikipedia.org/wiki/High-rise_syndrome
- pdkl95 8y agoThis is almost certainly survivorship bias[1]. Only middle-height cats that might theoretically survive are going to be taken to a veterinarian; the cats that fell from higher heights were not included, because they were "obviously dead". Which makes "high-rise syndrome" an example of the exact type of bias discussed in this paper. [1] https://en.wikipedia.org/wiki/Survivorship_bias#In_cats https://en.wikipedia.org/wiki/Survivorship_bias#In_cats
- 8y ago
- delinka 8y agoThis title has been editorialized from "Parachute use to prevent death and major trauma when jumping from aircraft: randomized controlled trial" to "Parachutes prevent death when jumping from aircraft: randomized controlled trial"
- throw-far-away 8y agoIt would suck to be in the control group. ;) Also, as my grandfather was a paratrooper: parachuting isn't a risk free activity even when the main canopy deploys properly, i.e., broken limbs on landing. And it's remotely possible to survive a fall without a parachute from terminal velocity height, i.e., Vesna Vulović. Edit: <- Edge-cases contrary to the obvious.
- txcwpalpha 8y agoThe control group in this study only fell a couple of feet at most. I don't think it sucked much for them at all.
- throw-far-away 8y agoSmh. Poe's law disclaimer wink added.
- txcwpalpha 8y agoHa! Fair enough. I'm leaving my comment just in case other people really do misinterpret the study.
- raphlinus 8y agoI believe that's an extremely subtle meta-joke on how popularizations of clinical trials always manage to mis-state what can actually be concluded from the trial. If so, well done. If that wasn't an intentional joke, even better.
- mlthoughts2018 8y agoI know this is a boring response, but I feel like there’s a formalism here to consider why a RCT would be “obvious.” Let’s say you’re going to use some causal model, like a regression adjustment technique. You could for example assign people to the treatment group (receives parachutes) and the control (no parachutes), and then observe who lives and dies, as well as a bunch of potential confounders like altitude, age, fitness, whatever. Fit a logistic regression to predict the outcome (survival) based on the treatment (parachute) controlling for the other characteristics. Then read off some effect size and ststistical significance. Or better yet, and here’s the important part, you could make it a Bayesian logistic regression by considering prior distributions for the regression model’s fitted coefficients, and sampling draws from the posterior distribution of coefficients using the data set and your priors. So what is the prior on the coefficient for the treatment term (parachutes)? Well, probably pretty damn high. Definitely some strongly informative prior, take your pick of historical data or effectiveness rates of physical safety equipment, whatever. From this prior, and making some neutral assumptions via the priors on other weights, you could figure of what the effective sample size would be for a data set to disconfirm your prior (e.g. a posterior with a mode on the parachute coefficient far away from your strong prior). Sort of like a power analysis, but assuming a fake data set that shows nothing but failed parachutes. How much of that silly data would you need based on your prior? What this would tell you is that you’d need some insane, physically ludicrous amount of data that flies in the face of an obvious prior, that what would be the point of running the study? You’re just going to confirm your prior. So the real question is how often is this a realistic description of other situations when you want to study a treatment? That’s the thing, right? That the author kind of wants to be snarky about. But really, it’s pretty fair to say you don’t have such a strong prior that the study would be futile, even in cases when you sort of do feel like the conclusion is obvious (e.g. taking Tylenol leads to less pain, college kids prefer drinking instead of homework). While it passes some gut test of what’s obvious, that’s different from really betting on such a one-sided prior that a study is futile. To me it suggests most of the sort of “duh” RCTs carried out are pretty much fine. Whether or not the study is worth it or is informative would be based on other priorities like cost, licensing or certification requirements, whether it’s of value to specialists who care about splitting hairs on accurate effect size measurement, etc.
- 8y ago
- calibas 8y agoThis isn't just for giggles. It's evidence that when there's a high perceived risk, "normal" people don't sign up for trials and it skews the results.
- stcredzero 8y agoA coworker of mine once made this proposal. 5 of us would start a company. The company would buy key man insurance for everyone, then go on a company team building trip. On this trip, we'd all skydive, but one of the 5 parachutes would be non-functional...Profit! This coworker of mine soon after left the company by storming out of the meeting room and slamming the door, then took up playing online poker for a living.
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- nostrademons 8y agohttps://en.wikipedia.org/wiki/Tontine https://en.wikipedia.org/wiki/Tontine
- porpoisely 8y agoAnyone else get acquainted with tontine from the simpsons? I watched that episode as a kid and still remember it to this day.
- twiceaday 8y agohttp://www.simpsonsworld.com/video/320768579741 http://www.simpsonsworld.com/video/320768579741
- masonic 8y agoI learned about them from a MASH episode in which Colonel Potter was the last surviving member of a WW1 tontine.
- superflyguy 8y agoNo, The Butt by Will Self.
- latchkey 8y agoThat's awesome, thanks! So is this: https://tontine.com/ https://tontine.com/
- xvilka 8y agoBut not a placebo-controlled one? Shame.
- ericye16 8y agoThe current title "Parachutes prevent death when jumping from aircraft: randomized controlled trial" is exactly the opposite of the article's conclusion: "Parachute use did not significantly reduce death or major injury (0% for parachute v 0% for control; P>0.9)." Nor is it the title of the actual article.
- qwerty456127 8y agoWhy do people use parachutes then? I felt like I'd like to have a parachute jump experience one day, do you mean that would equal jumping without a parachute (guaranteed death)?
- steve_musk 8y agoIt’s not guaranteed, there’s numerous cases where someone’s parachute malfunctions and they land with only broken bones and bruises.
- qwerty456127 8y agoI know but I have chosen to simplify the idea as the chance to survive (and recover your health to the level at which you won't regret you have survived) is negligibly small.
- pitaj 8y agoThe trial is essentially a joke. Here's some more context: > participants included in the study were on aircraft at significantly lower altitude (mean of 0.6 m for participants v mean of 9146 m for non-participants; P<0.001) and lower velocity (mean of 0 km/h v mean of 800 km/h; P<0.001). So essentially they had people jump about 2 feet from an airplane sitting at rest. Of course there were no injuries, and that was the point. Few people will participate in a trial in which the control group could die, and such a trial would be highly unethical.
- lallysingh 8y agoThe current title serves the point of the article quite well.
- lygaret 8y ago> The study also has several limitations. First and most importantly, our findings might not be generalizable to the use of parachutes in aircraft traveling at a higher altitude or velocity. Consideration could be made to conduct additional randomized clinical trials in these higher risk settings. However, previous theoretical work supporting the use of parachutes could reduce the feasibility of enrolling participants in such studies.16 > 16. Newton SI. Law of Universal Gravitation.Philosophiæ Naturalis Principia Mathematica, 1687.
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- frabbit 8y agohttps://www.bmj.com/content/327/7429/1459 https://www.bmj.com/content/327/7429/1459 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1584330/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1584330/
- lucisferre 8y agoAnyone know if these results have been reproduced by anyone? I'm a bit skeptical.
- paulcole 8y agoAssuming you’re serious, you can reproduce this yourself. Put on a backpack, stand on a chair and step off. The trial participants “jumped” from 0.6 meters.
- EamonnMR 8y agoI wonder if they where gunning for an Ig Nobel Prize. I'm sure they'll be nominated.
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- Fomite 8y agoThey were submitting to the BMJ Christmas Issue, which is an excellent read every year. Usually a bit of satire and humor mixed in with interesting methods.
- peterwwillis 8y agoWhen can we expect a news article telling people scientists advise not to wear parachutes?
- walrus01 8y agoI think this is like the medical research paper version of the famous RFC for IP over Avian Carriers. https://tools.ietf.org/html/rfc1149 https://tools.ietf.org/html/rfc1149 https://tools.ietf.org/html/rfc2549 https://tools.ietf.org/html/rfc2549
- jxramos 8y ago> PArticipation in RAndomized trials Compromised by widely Held beliefs aboUt lack of Treatment Equipoise (PARACHUTE) That has got to be one of the most torturous acronyms I've ever seen. That's a bit of a stretch.
- Fomite 8y agoOh my sweet summer child... Biomedicine has gone whole hog into torturing acronyms to make useful sounding cohort names.
- avar 8y agoAlso NASA. They just landed InSight on Mars. Interior Exploration using Seismic Investigations, Geodesy and Heat Transport. Most of the names are something where they're clearly trying to squeeze out a cute cohort name at all costs.
- jkim1258 8y agoMust have been a fun IRB approval process. Wish we could also see those applications/disclosures! >Ethical approval: This research has the ethical approval of the Institutional Review Board of the Beth Israel Deaconess Medical Center (protocol no 2018P000441).
- yason 8y agoI've always known the parachute manufacturers mostly ride on fear, uncertainty and doubt on this. They ruthlessly cash in on people's lack of knowledge and fear of death, advertising parachutes as a safer option which people buy because it's like insurance; if you'd happen to fall, you'd at least want to feel having prepared. So I'm glad to hear there's now some scientific evidence pointing to the futility of parachutes. Surely, the experiments were carried out in a constrained environment with some unavoidable assumptions baked in but it does rather convincingly suggest that parachutes consistently do not offer any help in the event of freefall. A corollary might appear that parachutes might even do more harm, adding weight to the falling person which could cause further injuries unnecessarily upon touchdown. I'll look forward to follow-up research. The big question is how would altitude affect the results. For experiments at higher altitudes they might need to locate an airstrip situated on a mountain, with enough runway to allow larger planes to land there and enough free space on the tarmac for several planes while they carry out the jumps. It will likely shed much more light and build confidence to the applicability of this new research and the obvious conclusion. Also, I'd like to see jumps done from different kinds of aeronautic vehicles, by more people, different brands of parachutes etc if should there be any differences regarding that. But it looks like after a few rounds of serious experiments we should quickly conclude the benefits are thin and see no need for excess research but, rather, reaching a steady conclusion.
- ainiriand 8y agoI suspect that landing on water has no discernible effect on the health of the suspect. And he will be completely soaked, so avoid jumping over water and always try to land on land.
- akavel 8y agoNotably, as to choosing land vs. water when falling from high altitude, see the ever fresh: https://news.ycombinator.com/item?id=11748528 https://news.ycombinator.com/item?id=11748528
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- dashmatte 8y agoHow come humor for smart people causes you to chuckle but not much else?
- flippyhead 8y ago> A key strength of the PARACHUTE trial was that it was designed and initially powered to detect differences in the combination of death and major traumatic injury. Although the use of softer endpoints, such as levels of fear before and after jumping, or its surrogates, such as loss of urinary continence, could have yielded more power to detect an effect of parachutes, we believe that that our selection of bias-resistant endpoints that are meaningful to all patients increases the clinical relevance of the trial. I love how much detail into which they go.
- peterburkimsher 8y agoTheir methodology has some serious shortfalls ;)
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- jusssi 8y agoIn case anyone else got curious about parachuting injury statistics, Google found me this (also cited by the article): "Parachuting injuries: a study of 110,000 sports jumps", 1987, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478603/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478603/ All 6 deaths they observed, were either failures to activate the parachute (4 cases), or parachute malfunction (2 cases).
- dohow 8y agoSome comments have touched on a few of these points but I’ll try to bring them together. So first, yes the headline is a joke (BMJ Xmas has satirical content), but it also has a history beyond the immediate point of the paper—that sometimes RCTs can’t accrue properly to a control arm to fairly evaluate an intervention. Quick points: - There’s a history to this analogy and paper within biomedicine and this journal (BMJ) from a 2003 article, which I’ll get to. - Parachutes are a dangerous metaphor in medicine, where almost nothing has an absolute risk reduction of >99% (note: not 100% because, yes, a handful of people have survived falling from altitude without a parachute), especially over the time-frame of a matter of hours. - This should not be a call to stop attempting RCTs (which is the conclusion some commenters have made), but an exhortation to find ways to create better ones when conditions are challenging. Frequently, objections to doing an RCT because “how could we withhold X from the control arm!”, are not as obvious once the data are in. Some background: beyond Retraction Watch looking for outright fraud, there’s a movement toward opening trial data for analysis because abuses in RCT design/analysis/reporting have gotten more criticism and attention lately. This is happening at the same time as the FDA has been moving toward lower/faster evidentiary standards for approval (see Sarepta controversy and general guidance in 21st Century Cures Act to allow drugs to market with earlier phase evidence and based on “surrogates” like was the tumor 2in vs 3in bigger vs hard endpoints like “did this person die later than the control”), so it couldn’t come at a better time. The broader point is that the 2003 “parachute” article in the same journal (BMJ), was frequently incorrectly understood / used. While “parachutes” makes an easily understandable headline, it is almost totally unrelated to the field of medicine where we rarely have a shot at doing something as obviously lifesaving as making someone hit the ground at 10 mph vs 120 mph. The problem is that people have cited the 2003 paper mentioned in the thread to justify a number of interventions that ended up not being better than prior care. The interventions were started in good faith because was “obvious” to their creators that doing X would be helpful (spoiler: it usually wasn’t or wasn’t that beneficial). A lot of this is cribbed from Vinay Prasad, who has a twitter thread about this: https://twitter.com/VPplenarysesh/status/1073298754298556416 https://twitter.com/VPplenarysesh/status/1073298754298556416 He is a controversial figure, but I think he does a good job of hammering home some important skepticism about a great deal of medical literature and practice to a broad audience. I’d appreciate hearing objections to the above, btw.
- jdlyga 8y agoI'd hate to be part of the control group.
- imh 8y ago> The PARACHUTE trial satirically highlights some of the limitations of randomized controlled trials. Nevertheless, we believe that such trials remain the gold standard for the evaluation of most new treatments. The PARACHUTE trial does suggest, however, that their accurate interpretation requires more than a cursory reading of the abstract. Rather, interpretation requires a complete and critical appraisal of the study. I love this paper. Whenever you see pop news articles saying "Study shows X is good/bad for you," if you dig in to the paper, it's often something like this. When you read the specific details, you realize the study doesn't generalize to "You should/shouldn't do X." But not enough people read the details, so it gets circulated into conventional wisdom :(
- stevespang 8y agojokes on you: "the trial was only able to enroll participants on small stationary aircraft on the ground"
- mormegil 8y agoImmediately sprung to my mind: http://www.lukesurl.com/archives/comic/444-fall-in-all http://www.lukesurl.com/archives/comic/444-fall-in-all
- j7ake 8y agoN=92 participants is not big enough of an N to conclude anything. To see differences you're going to have to go up to 10 times more at least.