Finding evidence-based medicine on the internet

Key Points

Google, the gargantuan answer machine in cyberspace, may strike you as a poor resource, particularly when you can turn to authoritative health care sites to research a diagnostic clinical problem. But, Google has more medical credentials than you might imagine. Google Scholar (http:// http://scholar.google.com/), for instance, searches only scholarly literature, weeding out online pseudo-science. And with a Google tool bar embedded in your Web browser, it's just as tempting to type in "epistaxis" as it is "American Idol."

Two Australian doctors put Google to the test recently and came away impressed. They selected 26 diagnostic cases published in The New England Journal of Medicine during 2005 and, without reading the differential diagnoses and conclusions, queried Google using search terms derived from each study. They reported in the British Medical Journal (BMJ) last December that Google guided them to the correct diagnosis in 15 of the 26 cases. For example, searching on "bullous skin conditions," "respiratory failure," and "carbamazepine" yielded the correct answer of "toxic epidermal necrolysis syndrome." The authors' conclusion: In difficult cases, it is often helpful to "google for a diagnosis."

Mixed reviews from the EBM world

Another bad review comes from Eamon Armstrong, MD, a family physician at Northern Arizona University who teaches other physicians how to find evidence-based medicine, or EBM, on the Internet. EBM is all about treating individual patients in light of the best available research, says Armstrong, and Google is not precise enough to locate it in most situations.

"The cases in the BMJ article deal with diagnoses so uncommon that most physicians will never make them in their lifetime," Armstrong says. "Google is useful for them, but not for common conditions where presenting complaints are vague, like 'nausea, fatigue, generalized muscle pain.' Google would yield a morass of disorganized information with no built-in quality filter. I can't think of a single person in the EBM field who would use Google on a regular basis."

Armstrong says that the BMJ study would have been more convincing had it compared Google with EBM search engines such as the Turning Research Into Practice or TRIP Database. Interestingly enough, Jon Brassey, a co-founder and co-director of TRIP ( http://www.tripdatabase.com/), holds Google in higher regard. "Google isn't anywhere near as good as TRIP," Brassey wrote in a blog. "But it's pretty fine."

Google was one of the reasons why Brassey stopped charging people to use the TRIP database last September. "Why should people pay for TRIP when they could use Google?" wrote Brassey, an information specialist with the National Public Health Service for Wales in the United Kingdom. "If I was hard-pressed financially, I wouldn't bother subscribing to TRIP."

How the CDC helps focus Google searches

Brassey does fault Google for not being transparent about its search and rank methodology, which, he says, often ranks older journal articles higher than recent ones. Although the company's search-engine algorithms are proprietary, at least part of what Brassey complains about may be a reflection of the value "label" placed on any given piece of information by recognized medical sources.

To see how that works, type in "hypertension" on the main Google search engine. In addition to ranked results, you'll see links to eight categories: Treatment, symptoms, test/diagnosis, cause/risk factors, for patients, for health professionals, from medical authorities, and alternative medicine. Click on "for health professionals," and more categories pop up, such as "practice guidelines" and "patient hand-outs."