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HFE for Over-the-Counter Medical Devices and Combination Products: Nice to Have or Necessary?

Human factors experts Tamara Will and Tricia Gibo weigh in the necessity of human factors engineering (HFE) work when designing over-the-counter (OTC) healthcare products.

Helping a person with a walker.

January 26, 2021

If you work for one of the many companies developing an over-the-counter (OTC) medical device or combination product, you might be wondering: Do I need to conduct human factors/usability work? And if so, what activities should I perform? Through this blog post, we will help you answer these questions for your individual case.

Definition of over-the-counter (OTC) healthcare products

First, when is something considered an OTC product? An OTC product is available without a prescription, such that it can be sold directly to the general public without seeking treatment or consultation from a healthcare professional (HCP). The latter is especially important to take into account when designing the OTC product, as the lack of HCP involvement means that users must be able to self-diagnose, self-treat, and self-manage their condition. Example OTC products include nasal sprays, wart removal devices, self-tests (e.g., pregnancy tests), and laser hair removal devices.

US FDA HFE-related guidance documents

In addition to the US Food and Drug Administration’s (FDA) general human factors engineering (HFE) guidance document, the FDA also has published specific guidance documents for OTC drug products that focus on label comprehension and self-selection. These HFE-related OTC drug guidance documents require statistically powered studies to examine whether consumers can understand the labeling (i.e., label comprehension) and correctly decide whether the OTC drug is appropriate for them to use based on their personal medical situation (i.e., self-selection). Notably, these guidance documents are not specific to combination products and medical devices, but sometimes the FDA does request these types of studies for these types of products. That said, there is no specific guidance for OTC medical devices or combination products.

OTC-specific considerations for HFE activities

Because there is no specific HFE-related guidance for OTC medical devices or combination products, we recommend referring to the FDA’s general HFE guidance document. As such, you should (at a minimum) identify the intended use, users, and use environments; conduct an analysis of known problems; and develop a use-related risk analysis (URRA) – similar to prescription (i.e., non-OTC) medical products.

Importantly, although a use-related risk analysis for prescription products can assume that an HCP is responsible for determining whether an individual is part of the intended patient population, this is not the case for OTC products. As such, the URRA for an OTC product should also consider risks related to potential users misdiagnosing themselves, or overlooking or misunderstanding contraindications, resulting in non-intended users using the product. For example, if a contraindicated person (e.g., under-aged, pregnant, implanted with pacemaker, with severe instead of mild symptoms) uses the product, what is the potential harm (e.g., experienced side effects, missed clinically relevant treatments) that could result?

As with other medical products (including prescription products), the scope of expected HFE work (including whether to conduct a human factors [HF] validation test) will depend on your use-related risk analysis. Specifically, if you have identified critical tasks (i.e., tasks associated with highly-rated risk), you will need to conduct an HF validation test; if you have determined there are no critical tasks, you could write a justification explaining why an HF validation test is not necessary.

Although not formally required, we strongly recommend performing formative evaluations, such as conducting a formative usability test. For example, a formative usability test can include an assessment of participants’ ability to understand important information on the labeling (e.g., indication for use, dose, warnings, when to stop using the product) for safe and effective OTC product use. Results from such a usability test can then be used to inform and optimize labeling modifications. Although OTC medical devices and combination products are not within the scope of the FDA’s label comprehension study guidance for OTC drug products, this guidance can be used as inspiration for how to design and conduct a formative usability test with similar objectives.

We also recommend evaluating consumers’ self-selection decisions, which can be incorporated as a use scenario in an HF validation test (if deemed necessary based on your use-related risk analysis), or potentially as a standalone test. In our experience, despite the lack of specific guidance, the FDA has sometimes requested that OTC medical device and combination product manufacturers perform a self-section study. Such a request might come about because the product is changing from a prescription to OTC status, there is no predicate, or there is a new indication. If the FDA has specifically requested a self-selection study, we highly recommend having discussions with the agency to fully understand their expectations – for example, a statistically powered study in strict compliance with the OTC self-selection study guidance might not be necessary, but rather a study loosely based on the guidance might be sufficient.

Either way, here are a couple of extra things to consider when conducting a test to evaluate self-selection:

  • Include participants with varying levels of literacy, in particular individuals who have been assessed (e.g., via the Rapid Estimate of Adult Literacy in Medicine (REALM) test) to have low literacy skills (also applicable for label comprehension studies)
  • Include participants who have contraindications to use the product, potentially targeting a specific population of interest depending on the identified risks and study objective

Conclusion: The benefits of HFE for OTC products

Finally, don’t despair if your product requires a greater extent of HFE work. HFE is not only a regulatory requirement; it also helps improve your product and make it more user-friendly for the intended users. Good HFE can help determine whether, as consumers walk down pharmacy store aisles, proper intended users not only correctly self-select your product, but perhaps are even more likely to decide to buy your product based on recommendations from others. And the effects of good HFE continue after the initial purchase, as a well-designed product can further enable consumers to independently use your product safely and effectively, with fewer customer complaints and use-safety issues.

Tamara Will and Tricia Gibo are Senior Human Factors Specialists at Emergo by UL’s Human Factors Research & Design division.

Learn more about HFE and user-centered design for healthcare products:

  • HFE user research support for medical devices, IVDs, and combination products
  • Medical device and product evaluation
  • Webinar: Human factors engineering for medical devices
  • Webinar: Safe in-person usability testing during COVID-19

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