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View Full Version : Horrible Medical Study Methodology


iron81
06-25-2007, 01:29 PM
Chicago Tribune (http://www.chicagotribune.com/news/nationworld/chi-mrsa25jun25,1,1355761.story?coll=chi-news-hed)

I read a story today on the front page of the paper talking about how 48,000 people are dying from drug-resistant Staph infections in hospitals each year. Here's how the story came to that conclusion. It doesn't look like the actual study has been released yet on the group website (http://www.apic.org//AM/Template.cfm?Section=Home):

- They sent out a survey asking hospitals how many staph infections they had on a particular day and extrapolated that to the number of infections. So far, so good, even though this number is 10 times the previous (CDC) estimate of Staph infections.

- They point out that the previous estimate counts about 5,000 deaths/year from Staph infections.

- They then use this to say ZOMG! 48,000 Staph deaths/year.

The reason this is horrible is because a staph infection that leads to death is much more likely to be detected. The much larger number of Staph infections is due to hidden illnesses that are undetected, but obviously there won't be many undetected illnesses that lead to death. It might be a mistake by the reporter, but it sounds like they are quoting the study. It just puts me on tilt when non-peer reviewed studies make the front page with methodolgy so horrible I can pick it apart from the article.

vhawk01
06-25-2007, 02:19 PM
This is pretty terrible, but no real surprise when medicine and journalism collide. I'll reserve judgment until the actual study comes out, although I wouldn't be entirely shocked to discover that this actually IS the reasoning used. The medical literature is chock-full of this type of 'science.'

iron81
06-25-2007, 02:36 PM
The study results (http://www.apic.org/Content/NavigationMenu/ResearchFoundation/NationalMRSAPrevalenceStudy/MRSA_Study_Results.htm) are out and it looks like the Executive Summary does not make any claims about Staph mortality. Would someone mind double checking that or find the actual study before I send a pissy letter to the editor?

vhawk01
06-25-2007, 02:49 PM
[ QUOTE ]
The study results (http://www.apic.org/Content/NavigationMenu/ResearchFoundation/NationalMRSAPrevalenceStudy/MRSA_Study_Results.htm) are out and it looks like the Executive Summary does not make any claims about Staph mortality. Would someone mind double checking that or find the actual study before I send a pissy letter to the editor?

[/ QUOTE ]

I'll look for the actual study but I'm not at school so I don't have unlimited access to every journal. If it isn't freely available I'm probably not going to be able to find it from home.

iron81
06-25-2007, 02:53 PM
That's one of the things that chaps me: its not in a journal. Its not peer reviewed. It's just something this group has done and issued a press release. I mean, I expect this kind of garbage from the local news "Health Beat", but I had respect for the Tribune.

vhawk01
06-25-2007, 03:00 PM
So, I read the Executive Summary as well as the survey instrument. Seems pretty solid to me. Nowhere did they mention any silly, erroneous extrapolation of MRSA deaths. The survey was comprehensive and fair. The sample size was pretty huge, including 21% of all facilities and 28.4% of all hospital traffic. Those are huge numbers, and make the data a lot more solid and representative.

I'd have to say the blame falls on the journalists in this one. No surprise there.