In medical education, it is often taught that clinical reasoning and judgment should support any orders for diagnostic tests to be completed. That is, the key question to ask when placing an order is: What do you plan to do with the test result? If you can’t come up with an answer, then reconsider ordering the test. If we think back to grade school science class, this is like a small-scale application of the scientific method in every clinical scenario: make observations, develop hypotheses, collect data, see how the results compare to the hypotheses, then refine and repeat as needed. (Wikipedia offers a quick review of the scientific method.)

In our rapidly expanding world of digital health, we have an abundance of data and tools with which to collect that data. With cheaper and more ubiquitous technologies, consumer health offers an expansive market of easily accessible wearable devices and apps for one to quantify oneself in as many and various dimensions as desired. It is estimated that more than 165,000 mobile health apps existed in 2015, and health apps account for more than 90% of consumer app downloads. But then the important questions need to be asked: Why do we want these data? How long do we plan to collect and use these data?

To critically and thoughtfully quantify oneself, it helps to don your citizen scientist hat (more on citizen science here and here) and be your own subject in a n-of-1 study. Then, apply – even if a bit loosely – the principles of the scientific method when you decide how to collect your data. If you are considering picking an app or wearable to collect personal data, here are a few considerations when you make your choice:

  1. Describe your health goal. Returning to the original question above, what do you plan to achieve with your personal experiment? Your health goal could be as common as using a wearable to track your daily step count, and adjusting your activity levels to aim for walking at least 10,000 steps per day, with the overall goal of increasing your daily physical activity. If you have borderline high blood pressure, and you are reducing sodium intake, aiming to avoid taking antihypertensive medications, using an app to enter your blood pressure readings, or a Bluetooth connected blood pressure cuff and app, can be the right choice to help you self-manage your health and wellness (in combination with discussion with your health care provider, in this case). Other apps track self-reported symptoms to guide self-management as well, like the Department of Veterans Affairs app for post-traumatic stress disorder. Regardless of your goal, it’s important simply to have one; while it’s perfectly acceptable to track your data simply “to know” or just for fun to try a new technology in the absence of health conditions, it’s also possible that non-clinically significant events might be sporadic or purely incidental findings and creating unnecessary worry about your health should never be the goal of any app or wearable.
  1. Be critical of what apps claim they can do for you. Keep in mind that most mobile apps and wearables in the health and wellness spaces are new, and federal regulatory standards are still evolving around such apps. There are recommendations as to what are considered tools for general wellness and tools that must be distinguished from medical devices, since medical devices* are under a separate, more well-established and stricter set of regulatory standards. Make sure you are not buying into marketing tactics that lure you into investing personal resources – times, energy, money, and maybe even a bit of worry – into a product that does not support your achieving your health goal. Also, data quality is essential; if data collected with your app or wearable are not accurate, how can you rely on them to make healthy choices? Read reviews of these apps and wearables, as other consumers may have already tested or compared them with an external standard or other sets of apps or wearables already.
  1. Consider the risks of an app or wearable. First, the FDA criteria to categorize risk of an app or wearable seem commonsense enough: Is the product invasive, implants, or could it pose a safety risk to the user or others? If yes to any, then reconsider its use. Also consider the indirect risks, such as the privacy and security issues around your health data. Apps are designed by software developers and companies that can request that you grant them access to smartphone data or data from other already installed apps. Take a moment to consider what exactly the app is asking to access. You are potentially agreeing to share your phone data with a third party and when you quickly tap “Accept” to proceed with installation, you are trusting them with your existing data and the data you plan to track using the app. Finally, you also want to consider who created the app; in my last post I recommended identifying the source of online health information, and evaluating an app should be no different.
  1. Consider sharing your data with your health care provider or asking for suggestions. Start a conversation with your health care provider if you are ever unsure of the merit of claims made by apps or wearables, or you think you might try one to benefit your health and wellness but aren’t sure where to begin. While the integration of data from apps and wearables into routine clinical care is still a work in progress, this is an opportunity to open new dialogue around learning about and taking the lead in managing your health.

*According to FDA guidance, “when the intended use of a mobile app is for the diagnosis of disease or other conditions, or the cure, mitigation, treatment, or prevention of disease, or is intended to affect the structure or any function of the body of man, then mobile app is a device.” (Emphasis added.)

Tiffany Leung

Author Tiffany Leung

Tiffany I. Leung, MD, MPH, FACP is a Clinical Assistant Professor of Medicine at Stanford University School of Medicine. She is also board certified in Clinical Informatics and has a particular interest in how technology can be used to ensure that patients have a better understanding of their health profile.

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  • Vincent says:

    Very nicely written. I didn’t know 90% of downloaded apps are health related! We are obsessed with using apps. ” When you have s hammer, everything looks like a nail”☺
    Also I perfectly agree with sharing your phone data is risky.

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