Keeping the Human Connection in Drug Delivery Device Development

Drug delivery devices have changed a lot over the years. The humans who use them? Not so much. Sometimes, the very features that were intended to help patients end up causing confusion instead. 

As we continue to add functionality and connectivity to drug delivery devices, we need to make sure that we are keeping humans at the center of device development decisions. Human factors studies illuminate potential use errors before irreversible decisions about a device’s design are made. That saves device manufacturers the time and high cost of late-stage device redesign and, even more importantly, protects patients from the risks of foreseeable misuse errors. 

The Rise of Connected Drug Delivery Devices

Modern drug delivery devices are much more sophisticated than devices from previous eras. Many of them are packed with sensors and electronics that allow them to track dose delivery and timing and provide instant feedback to patients so they know whether or not a dose has been successfully delivered. Many devices are now also connected to programs and apps, either through cables that allow data to be transferred or through wireless connectivity. 

Connected drug delivery devices have tremendous potential benefits for patients and caregivers. 

• They enable automated tracking of when each dose is delivered and how much has been taken, allowing patients, doctors and caregivers to see dosing history.

• They can alert patients when they are getting low on medication or even trigger automated communication to doctors and pharmacies for just-in-time refills.

• They can even connect the device to sophisticated systems and apps that enable closed-loop drug delivery, remind patients when a dose is due, or trigger alerts for caregivers or doctors if a patient is not taking a medication as prescribed. 

Done right, smart, connected drug delivery devices improve patient safety, adherence, and doctor-patient communication. But the more features that are added to the device, the more demands are placed on the user. Patients may need to download an app to a smartphone and learn how to use it. They may have to take specific actions to ensure that data is transferred to an app or program for tracking and monitoring. They may need to learn how to interpret different sounds, flashing lights, or error codes to determine whether the device is ready to use or whether a dose has been successful. All of this is much more complicated than simply pushing a plunger on a traditional syringe or autoinjector. 

The Importance of Human Factors Studies for Connected Drug Delivery Devices

Designers and engineers make educated assumptions in the course of developing a new drug delivery device. Some of these assumptions are overt: for example, we may assume that the meanings of red and green lights are intuitive for people who have grown up within our cultural context. Other assumptions may be implicit or even hidden. We may assume certain things about our users’ physical abilities (such as their visual perception or hand dexterity), cognitive abilities (such as their ability to follow sequential instructions or navigate a smartphone app), or language background without consciously thinking about it. These assumptions drive device development decisions, whether they are conscious or not.

Human factors studies put these assumptions to the test. These studies put design concepts, physical prototypes, instructions and software, or actual devices into the hands of potential users. Users may be asked to respond to researchers’ questions or simply to engage with the device as if they were using it alone at home. Watching real people in the target population interact with drug delivery devices can show us where we have made unfounded assumptions. Often, we see people using devices in ways that may be contrary to our expectations. 

For example, we conducted a study of an autoinjector device that connects wirelessly to a smartphone app that records the dose time and amount. Sometimes, the patient must perform an action (pushing a button in a certain way) to trigger the data transfer. The device provides feedback to patients through different sequences of flashing lights. 

While this seemed like a relatively simple operation (and it did not impact the ability to administer medication), the steps for this new feature caused confusion for many of the patients and caregivers in the human factors study. Some were confused by the sequence of flashing lights or did not know when they needed to push the button to transfer data. As a result of the study, the manufacturer will be able to make changes to the app and device instructions to address points of confusion. 

Getting the Most Out of Human Factors Studies

Medical device manufacturers can avoid costly mistakes by integrating human factors studies early and throughout the development process. To get the most benefit from human factors studies, there are a few points drug delivery device manufacturers should keep in mind. 

Consider your target population. From the very beginning of the design process, device designers should have a clear picture of the population of users who will be engaging with the device, which could include both patients and their caregivers. Then, they should carefully consider the assumptions that they are making about their users’ physical, cognitive and linguistic capabilities. Keep in mind that aging or disabled patients may respond very differently to a device than an “average” population. For example, older patients may not be as comfortable with technologies such as smartphone apps and may have low tolerance for frustration when learning new technologies. Device developers should always run human factors studies, making sure to include a broad representation of all of the user types who may be engaging with the device.  

Engage in human factors studies throughout the development process. Validation studies are the only human factors trials that are required for medical device developers for regulatory purposes. However, changes to the device once it reaches this point can be prohibitively costly and are likely to push back product launch dates or even prevent the device from going to market. Human factors studies in the conceptual, design and early prototyping phases can make sure your product design is on track for your users at a stage when making changes is much less expensive and quicker to implement. 

Watch, listen and learn. It is important to come into a human factors study with an open mind—remember, we are testing assumptions that designers may not even realize they have made. Watch how users interact with the device without interference and pay careful attention to their actions, behaviors and even facial expressions. These often tell you more than their words. 

Finding the Right Balance Between Function and Simplicity 

Designing drug delivery devices that meet the needs of patients and caregivers requires balancing functionality with ease of use. Remember, just because something can be connected doesn’t mean it should be. Device developers should ask themselves whether the connected feature is making the patient experience demonstrably better or simply adding unnecessary complexity. 

When we keep humans at the center of the design and engineering process, we can find a balance that works for both device manufacturers and their users. Human factors studies tell us when something is too hard, too confusing, or too intimidating for users. Studies can also suggest potential fixes. Sometimes, these are as simple as changing a user display on the device or in the app, simplifying the language in the instructions, or making a software change that reduces the number of actions the user is responsible for. Little changes in device design, software or instructions can make a big difference in the way patients respond to the device. 

Battelle works with medical device developers to design and conduct human factors studies that get to the heart of what developers need to know to make their devices safer and provide an enhanced user experience. Our human factors team has expertise in designing human factors studies and asking the right questions to help device manufacturers make effective development decisions. Integrating human factors studies into drug delivery device design and engineering can help manufacturers avoid costly development mistakes and create products that maximize patient acceptance, adherence and safety.