One of my passions is practicing and teaching evidence-based medicine (EBM). Many of the reviews I select to write on iMedicalApps are apps that connect the user to EBM. Our list of the Top Apps of 2017 is filled with EBM apps. But where should providers go for EBM stats? For busy primary care providers and any medical student, resident or even many residency faculty, applying EBM stats at the point of care is just too difficult. You can’t do the math in your head and the calculations going from pre to post-test probability is mind boggling. Many of the top medical references such as UpToDate, DynamedPlus, Essential Evidence, and Medscape contain great EBM information and some include useful stats such as the Number Needed to Treat (NNT) and Number Needed to Harm (NNH). However, these can be time-consuming to find and depending on your subscription/resource, may require an internet/cellular connection. Current medical calculators such as MdCalcQxCalculate, MediMath, and MedCalc (now MedCalx) include some of these basic EBM stats. So far the most complete EBM calc app is MedCalc 3000 EBM Stats, but it costs $9.99. The “best” free EBM Stats Calc app is by Dr. Joshua Steinberg which we favorably reviewed here in early 2018.

The problem with all of these apps is they do not guide the user from start to finish with the necessary data to make an actual diagnosis. Some apps such as Evidence-Based Primary Care, contain an enormous amount of useful pre-test probabilities and likelihood ratios, but that app must be combined with an app such as EBM Stats Calc to arrive at a specific post-test probability. One medical provider, Dr. William Wright, set out to create an all-in-one diagnosis app for infectious disease. Dr. Wright is an infectious disease specialist at the University of Pittsburgh. His app, iDx Essentials, is focused solely on common infectious diseases. The app guides the user from an initial stated and referenced (but adjustable) pre-test probability to a post-test probability and diagnosis using unique likelihood ratios for each ID condition (23 in all currently). The app also provides a detailed treatment section for each ID dx with numerous references.

Apps like iDx Essentials, EBPC, and EBM Stats Calc bring providers closer to making actual evidence-based/statistics-based diagnoses using just our smartphones at the point of care. One of the most revered EBM textbooks by Straus, et al. challenges providers to do just this very thing. Now at least for some common ID conditions, we actually can meet this challenge.

Evidence-based medicine

Dr .Wright’s iDx Essentials brings the most high-yield infectious disease EBM calculators to the iPhone. Using validated pre-test probabilities to start the calculations, the app allows users to click check boxes of various +/- likelihood ratios and/or other validated clinical decision tools to arrive at a final post-test probability. The app should greatly aide clinicians in making challenging infectious disease diagnoses. The app is well referenced and includes a detailed treatment section for each condition.

Who would benefit from this App?

Students, nurses, residents, mid-levels, faculty in any specialty (but certainly ID), any provider looking to perform EBM stats for ID conditions on their mobile device.

Disclaimer: The views expressed are those of the author(s) and do not reflect the official policy of the Department of the Army, the Department of Defense or the U.S. Government.

  • Price
    • Free
  • o Simple to use checkbox interface to move from pre-test to post-test probabilities

    o Includes detailed section on treatment for each condition with references

    o Available for Android

  • Dislikes

    o Only covers conditions in infectious disease

    o Some common ID conditions not included

    o No hyperlinks for references and some screen formatting issues

  • Overall

    An app like iDx may be what we are all looking for if you want to apply true scientific formulas, math, and EBM stats at the point of care. For the included infectious diseases, the app allows users to easily convert pre-test to post-test probabilities using validated likelihood ratios related to each condition. Furthermore, the app includes a brief overview and treatment section for each disease. The only drawback is the narrow scope of the app (infectious disease) and the absence of some common ID conditions seen in primary care.

  • Overall Score
  • User Interface

    Easy to use and nearly perfect with only a few minor layout quibbles.

  • Multimedia Usage

    App has numerous calculators using pre-test probabilities, likelihood ratios, or other EBM tools for calculating post-test probabilities for common infectious diseases. Includes copious references, but no hyperlinks.

  • Price

    App is free.

  • Real World Applicability

    iDX makes calculating post-test probabilities on common infectious diseases extremely easy. Instead of looking at separate signs, symptoms and lab tests, iDX puts them all in one place for each common ID condition. Furthermore, it gives evidence-based treatment recommendations. The only drawback is the number of conditions covered including some notable common primary care infectious diseases. Absolutely worth trying out in the clinic or on the wards.

  • Device Used For Review

    iPhone 8 running iOS 11.4

  • Available for DownloadAndroidiPhoneiPad