http://onlinelibrary.wiley.com/doi/10.1111/cea.12211/abstract (http://onlinelibrary.wiley.com/doi/10.1111/cea.12211/abstract)
The abstract (the full article is available free)
Quote
Background
Food allergy is a common cause of anaphylaxis, but the incidence of fatal food anaphylaxis is not known. The aim of this study was to estimate the incidence of fatal food anaphylaxis for people with food allergy and relate this to other mortality risks in the general population.
Methods
We undertook a systematic review and meta-analysis, using the generic inverse variance method. Two authors selected studies by consensus, independently extracted data and assessed the quality of included studies using the Newcastle-Ottawa assessment scale. We searched Medline, Embase, PsychInfo, CINAHL, Web of Science, LILACS or AMED, between January 1946 and September 2012, and recent conference abstracts. We included registries, databases or cohort studies which described the number of fatal food anaphylaxis cases in a defined population and time period and applied an assumed population prevalence rate of food allergy.
Results
We included data from 13 studies describing 240 fatal food anaphylaxis episodes over an estimated 165 million food-allergic person-years. Study quality was mixed, and there was high heterogeneity between study results, possibly due to variation in food allergy prevalence and data collection methods. In food-allergic people, fatal food anaphylaxis has an incidence rate of 1.81 per million person-years (95%CI 0.94, 3.45; range 0.63, 6.68). In sensitivity analysis with different estimated food allergy prevalence, the incidence varied from 1.35 to 2.71 per million person-years. At age 0–19, the incidence rate is 3.25 (1.73, 6.10; range 0.94, 15.75; sensitivity analysis 1.18–6.13). The incidence of fatal food anaphylaxis in food-allergic people is lower than accidental death in the general European population.
Conclusion
Fatal food anaphylaxis for a food-allergic person is rarer than accidental death in the general population.
Okay-- firstly, while the media and laypersons may think this is meaningful, it is NOT. In fact, I'd characterize the meta-study here as
hopelessly flawed, probably to the point of no use whatsoever.
- 1946?? Seriously?? IS there anyone on earth that thinks that the "food allergic" population in 1946 looked anything like a food allergic child born in 2006?? I think probably not. In fact, there is OPEN concern among clinicians and researchers alike that something has made children born after 1990 profoundly different patients than those who came before then-- more severely impacted, more food allergies, more risk, more prone to anaphylax, maybe even. So okay-- they've included data on people that probably shouldn't be grouped together to begin with.
- Is this not even broken out by ALLERGEN, for heaven's sakes?? Nobody in their right mind thinks that the average experience of a soy-allergic person is a good portrait of the average peanut-allergic one. Nobody. Some allergens are FAR more difficult to avoid, but some allergens are also far, far, FAR more likely to evoke anaphylaxis with potentially fatal features. This is really well-known, and has been for most of the past 50 years.
- Um, so with recognition rates and mis-coding as rampant as they are NOW-- what with international efforts to raise awareness over the past forty years or so... what in the HELL makes anyone foolish enough to think that the capture rate for "anaphylaxis" as COD was anything more than a fraction of a percentage of the true total in 1950?? People STILL get coded with asthma as the presenting issue, and this is NOW.
- Other studies estimate the liklihood of reaction at about 14% per annum in the current cohort of juveniles with peanut allergy-- this REALLY doesn't seem to tally well with that figure.
- How very, VERY convenient to post probabilities in comparison form on log scales. You know, as opposed to in bar charts with, er-- errors associated. Just noting.
Anyway. Those are the most serious flaws with this paper. There are others.
Oh, and as far as I can tell not one of the authors of that mess is an allergy specialist. Nope-- epidemiology, psychology, and pediatrics.
While I have to think that their hearts were in the right place-- anxiety IS a real thing, and a serious one-- the problem is that they've just contributed to making a highly vulnerable population even more disenfranchised by dismissing their completely rational level of concern.
By using bad science to accomplish what was (apparently) their primary goal to start with.
They even noted some of the weaknesses that I listed above. But then dismissed them, or ignored data from relevant high-quality studies that even I know about, in favor of obscure stuff that is too specialized/isolated in scope to truly reflect upon their conclusions. Bias, much?
Sheesh.
Well, ideally fatal anaphylaxis would go down over time as long as you hold constant the carrying and use of epinephrine appropriately either by patients, their caregivers or first responders/ER, practicing avoidance, labeling laws and manufacturer disclosure, 504 adherence in accommodations, prevalence and use of cell phones for 911, proximity to rescue squad and triage at hospital.
In that sense any study would have to adopt the same controls that one would need for measuring murder rates in relation to quality of emergency services and access. More life saving = less murder but not necessarily indicative of actual violent crime and shootings.
Which leads me to yet again think of it in terms of the LSAT questions that are purposefully flawed to identify the best answer that if true most weakens the argument.