App review: Health Check – Symptom Checker Review

Editor’s Note: Each month, physician reviewers will evaluatea particular app or category of apps that provide some functionality for medical practices and/or patients.

These days, anybody can attempt to determine their medical conditions. However, most individuals who aren’t physicians don’t have good ideas about how to diagnose the problem(s) or symptom(s) they are experiencing. The advent of computer software, the ability to parse large volumes of data, and the power of algorithms have made it possible to take a statistical and scientific approach to differential diagnosis. Whether this is an accurate and/or usable approach is an entirely different question.

Health Check – Symptom Checker Review was designed with a plug and play interface to allow users to determine a differential diagnosis by inputting the known symptoms. The app is clearly designed for non-medical people, even going so far as to put up obligatory warnings about using it and seeking professional help if needed. Company and lead design Cezar Popescu said in an interview with Physicians Practice that the goal was to create a desktop-based application that helped patients to check symptoms. His company, Day1 solutions, focuses on developing desktop-based software to do just that on the Mac OS X platform.

The app costs $4.99 from the Apple App Store and, as of this writing, was one of the top featured apps in the medical category. However, because it is relatively new, the app had only six ratings, though most are good. The app presents a fairly simple interface for users who choose an organ-graphically represented on a human outline-then use a drop-down list to identify their symptoms. The right half of the screen has a slider for users to indicate the intensity of each symptom. Users may add multiple symptoms for a single case and separately rate the symptom’s intensity. The intensity scale uses phrases such as low, moderate, and extremely high that, while descriptive, aren’t very specific.

The app becomes very interesting after users click on the “Find Diagnosis” button. At that point, the application spits back a number of potential disease processes along with the probability, expressed as a percentage, for each. Each disease process has an info button that provides additional information about the condition including a layperson description, gravity of the situation, incidence per 1,000 people, and commonly associated symptoms. Users can create profiles to save and track their symptoms over time.

Three physicians, from the Romanian town where the company is located, developed the database for the disease lists and percentages based on patient volumes and complaints. Lead physician Camelia Lacatusu is the mother of the software developer, and Popescu said she has more than 30 years of experience in internal medicine. The other two physicians are identified as a surgeon and neurologist. The data was cross-checked against online databases, although the databases were not specified. Lastly, the company states that algorithmic stability was assessed at each stage of the app’s development, although the process was not identified.

The real question is: How does this application measure up against other free online applications with a similar or identical functionality, such as WedMD’s Symptom Checker or the Mayo Clinic’s Symptom Checker?

I compared the apps using three relatively simple findings: blood in urine, lower abdominal pain, and frequency of urination. I entered them into the symptom checkers to see if they returned diagnoses of kidney stones and urinary tract infections (UTI). All three came to the same conclusions, but Health Check and WebMD were quicker and much more accurate. The Mayo Clinic’s Symptom Checker couldn’t get the right diagnoses from lower abdominal pain and took me down a very different path but corrected when I started with the symptom of hematuria. Health Check was the only one to give specific percentage probabilities, while WebMD used ratings of moderate and fair for matches.

Rating

Recommend to patients?: For basic evaluation only; not comprehensive or accurate enough for routine use.

The challenge here is that none of the tools returned kidney stones or UTI as the first or most likely diagnoses, which is what my random sample of residents and physicians consistently did. This simple test demonstrates that such tools are not likely to be effective as replacements for clinical evaluation. To be fair, all of the tools suggest that their use is limited and should prompt further evaluation by a qualified physician.

Keeping these disclaimers in mind, Health Check does an OK job of filling that need. The challenge will be to see if the company continues to update it. Popescu said they are planning to add 50-100 disease states over the next six months based on popularity of the app and broaden the symptom list.

The cost ($4.99), though minor, is surprising given the newness of the app and similar free tools on the market such as that offered by WebMD-a well-known resource for self-diagnosis-and the fact that such apps still require clinical evaluation. It is difficult to foretell if such a product has a public market, but it will be interesting to watch how patients choose to use such tools moving forward.