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A new article in the BMJ this week reports on a good, clever evaluation of 29 online symptom checkers, showing that some have a clue and some don’t. I love it; in my view the bottom line is “Some are better than nothing, none is near perfect, and some are junk. Learn, but as with all things online, be careful.”

The method used (described below) is clever: it’s not unlike the famous Turing test (Wikipedia), which examines whether you can tell the difference between a computer and a real person. (Answer: real doctors, while far from perfect, are a lot better than today’s websites.)

Today’s Boston Globe has a good front page article by Felice Freyer about it. SPM co-founder Susannah Fox, currently Chief Technology Officer at HHS, is quoted, as am I – it’s great to see participatory perspectives sought out by the Globe!

Method: evaluate websites the way we evaluate docs

I love the method used by authors SemigranLinderGidengil, and Mehrotra at Harvard: they fed each website a “standardized patient” scenario. “SPs” are how medical students are tested: a trained actor answers the student’s interview questions; the student’s job is to hone down the options to reach a correct diagnosis, and in this test that was the website’s job, too. (That’s the Turing-like aspect: respond to the website like you’d respond to a human.) The researchers answered whatever questions each site asked, and recorded its suggested diagnoses.

Sensibly, the authors didn’t just report on whether the website produced the right diagnosis at the top of its list; they also reported whether the right answer was in its top three. That’s realistic: anyone who searches online for travel options, restaurants, etc knows that people look at the top few results. Plus, if you’ve ever googled your symptoms, I’m sure you at least scrolled a bit.

They also reported how often the right answer was in the top 20, but, as they noted, hardly anyone ever looks there. (To me the usefulness of this number isn’t who got it right, but who still didn’t have the right dx. Think about it: any site that doesn’t have the right answer in the top 20 is just… well, worse than nothing, eh?)

Separately, they reported how well the sites did at triage – recommending whether you should see a doctor. Not surprisingly, the sites were generally loathe to say “You don’t need a doctor” – who would want to be sued for giving that advice, if it turned out to be a real problem? In our Society we know that patients are responsible for their own decisions: seek information online, be responsible and cautious, and in particular be responsible for your decisions about when to seek help.

How did the sites do?

Happily, the BMJ article is open access so you can go comb through the results tables yourself. Here’s my highlight list. In short, there was a huge range:

  • Correct diagnosis was listed #1: sites’ performance ranged from 50% of cases (DocResponse) to an abysmal 5% (MEDoctor). 50% is impressive for a robot that can’t see you, but still wrong half the time, eh?
    • Runners-up: FamilyDoctor 47%, AskMD 43%
  • Correct diagnosis was in the top three: sites’ performance ranged from 71% of cases (Symcat) down to 29% (Better Medicine).
    • Runners-up: Isabel 69%, AskMD 68%, DocResponse 67%, iTriage 64%
  • Correct diagnosis was not in the top twenty: these sites get the booby prize for not even having the right answer in the top twenty half the time:
    • Doctor Diagnosis only mentioned the right answer 46% of the time, Symptify 44%, MEDoctor 43%, BetterMedicine 38%, Symptomate 34%, and EarlyDoc 33%.
    • That’s just epically bad. I mean, what are they thinking inside that robot, if 2/3 of the time the right answer isn’t even in their top 20 guesses??? Was the robot stoned during class?:-)
  • Triage advice (“should I see a doctor?”) I’ll only comment on the ratings of “Is self-care reasonable with these symptoms?”
    • Correct: 62%, Harvard Medical School Family Health Guide 62%, Family Doctor 60%, Steps2Care 57%
      • Note: even the best of them is very often wrong.
    • Booby prize: These sites never said it’s safe to stay home (what??): iTriage, DoctorDiagnose, Isabel, Symcat and Symptomate.

The other half of the Turing test: how well do doctors do?

Diagnosis is difficult. We wrote about it here in 2011 (Action in the face of uncertainty), and the New York Times reported in 2006, “Studies of autopsies have shown that doctors seriously misdiagnose fatal illnesses about 20 percent of the time. So millions of patients are being treated for the wrong disease.”

Note: that doesn’t say “Doctors are wrong 20% of the time”! Autopsies are done on dead people, not people who survive. It just says that it’s not at all rare for docs to miss a diagnosis – because diagnosis is hard.

e-Patient takeaways

Our 2011 post ended with the question, “What do you do in the face of uncertainty? How many sources do you check before you decide to move forward?” So it is with symptom checkers.

In the Society for Participatory Medicine we’ve long known (since the pioneering work in the 1980s and 90s of “Doc Tom” Ferguson) that patients and families contribute more to healthcare when they’re empowered, engaged, informed; more information is a good thing. But we also know that although everyone would like certainty, we are all often operating in an atmosphere of our current best guess based on available facts.

e-Patient takeaways:

  • Diagnosis is hard. Don’t expect perfection anywhere. Keep an eye on whether the treatment seems to be working.
  • There’s a huge range of accuracy in symptom checker sites. (SPM past president Dr. Josh Seidman notes that the best site is ten times better than the worst … but even the best will be wrong a lot.) (See comment below for more on his work.)
  • So, get a second opinion – from another robot (another website).
    • If two agree, that’s a good sign – but they still might be wrong. If three agree, that’s even better – but still, don’t assume you’ve got it.

I’ll add this personal opinion (not an official SPM policy statement):

Do not go in to your clinician and say “I figured out I have condition x.” Go in and say “Before calling you I tried to learn what I could, and here’s what these sites said. What do you think?”

(I also recommend not bringing the famous eye-rolling “big stack of printouts” – a summary is enough. And if you’re really lucky, your clinicians will discuss it in email first!)

And for visionaries, policy people, and software developers, the best advice is not in the BMJ article but in Susannah Fox’s comment to the Globe:

“The reality is, people are using these tools and consulting Dr. Google whether we like it or not,” Fox said. “What this study shows is that we have an opportunity to open up a new avenue to reach people with quality information.”

Caveat: when business interests meet patient needs

A closing note: as a businessman involved in patient empowerment, two things stuck out to me.

  • The famous and much-viewed site WebMD has a symptom checker, and you’ll notice it’s not listed above – because it was perfectly mediocre, placing in the middle of the pack: #10 of 19 in the “Top 3” test. In the Globe article WebMD commented defensively: “Dr. Michael Smith, chief medical editor of WebMD, defended his website’s symptom checker, which gets about 4 million visits a month, and described it as accurate and helpful.” Really? If “We got the right answer in the top three 51% of the time” is your idea of accurate, do I trust your thinking??
  • And I have to ask, what’s going on with iTriage, owned by insurance company Aetna, never endorsing self-care, always saying “we recommend you spend money”??

So it goes when business meets healthcare, I guess: buyer beware; patient be wise.

SPM member Dr. Michael Mascia summed it up on our members-only listserv:

People and Patients still, yet and again need reliable physician partners … or, in the future whomever the designated healer of the moment may be … partner and partners will be needed.

Technology can help us deliver better and best health and health care and each of us (responsible adults) must carry the bulk of the burden to achieve best care and treatment.

But, when it comes to sick care … there comes a time when each of us needs help from other folks.  That’s when we need reliable partners.



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