User Needs in Medical Devices and Combination Products
Introduction: The Foundation for User-Focused Medical Devices and Combination Products
In my years of experience in the medical device and pharmaceutical drug delivery device industry, I’ve realized the key role of properly defining user needs for any medical device or combination product. Properly defined user needs are essential for developing effective, patient-centered drug delivery devices, but mostly to ensure the team doesn’t lose focus on the goal of creating the best possible solution for the user. By understanding how to properly define user needs, and how to translate them into user requirement specifications and design input requirements, we can ensure that the needs and expectations of both patients and healthcare professionals are translated into device development, helping innovation stay focused on our final users.
When user needs are not properly defined, teams often find themselves revisiting documentation and design inputs, leading to delays and added costs. A clear definition not only streamlines the development process but also ensures that devices meet usability and safety expectations. In the highly regulated environment that the pharmaceutical and medical device industry operate and where user errors can have significant consequences, the focus on user-centered design and regulatory compliance is particularly critical.
Understanding the Differences Between User Needs and User Requirement Specifications in Medical Devices
It is really important to understand the difference between User Needs and User Requirement Specifications (URS). Misunderstanding on these terms happens frequently and even today I still see some specifications that are formulated more as need than as requirement, confusion on these terms can lead to problems during the validation process and forcing the company to re-conduct some of their evaluations, creating extensive delays in their timelines.
User Needs
Represent the main goal or expectation that your intended users have and your device must satisfy. They are generally qualitative and focus on what users want or need from the device, such as ease of use, safety, and efficacy. For example, a user need might be that "the device must be easy to activate for elderly users with limited dexterity."
User Requirement Specifications (URS)
On the other hand, URS are detailed, measurable criteria derived from user needs. They translate the qualitative aspects of user needs into specific, actionable design inputs that guide the engineering and manufacturing process. For instance, a URS derived from the user need mentioned above might specify that "the activation force for the device must not exceed 2 Newtons."
This distinction is critical. From my experience, when teams clearly define user needs and translate them into precise URS, they are better positioned to create devices that not only satisfy regulatory requirements but also align with real-world user expectations. According to Greenlight Guru, this process bridges the gap between what users want and the technical requirements needed to build a compliant and functional device.
Clearly distinguishing these terms also facilitates communication between multidisciplinary teams, helping to align engineers, designers, and human factors specialists around shared goals. This alignment ensures that design inputs derived from URS remain tied to the original user needs, maintaining focus throughout the development lifecycle.
Meeting Patient and Healthcare Needs: The Role of User Research in User Needs definition
To truly understand your patients, the only proper way is to head into the field and investigate. This is something that anthropologists and UX researchers do really well. It’s always beneficial to have people on your team who are well-versed in exploratory techniques, as well as those specialized in validation and more formal human factors experimentation. These steps enable developers to understand user behavior, challenges, and preferences, forming a strong foundation for innovation.
One case that stands out in my experience involved designing an auto-injector for both elderly patients and adolescents. Observing these groups interact with existing devices revealed not only common challenges, such as difficulty with grip strength or understanding feedback mechanisms, but also unique opportunities to tailor solutions for each demographic. For example, adolescents often seek discretion in device use, which informed design features aimed at minimizing stigma, while elderly users required ergonomic adjustments to accommodate reduced dexterity and vision.
Insights from exploratory research led to features like enhanced grip textures, clearer instructions, and multi-sensory feedback tailored to the capabilities of each group.
During one formative usability evaluation, we discovered that users often ignored the visual feedback indicating dose completion. Interestingly, the reasons differed between user groups: some elderly users failed to notice the feedback due to visual impairments, while adolescents were easily distracted so they missed the visual feedback. This insight prompted the addition of a tactile confirmation mechanism, significantly reducing errors and improving user confidence across both groups.
On the other side, I experience unique challenges when developing medical devices for surgical doctors The intense environment of the operating room (OR), combined with the urgency and pressure of critical interventions, revealed gaps in usability that standard development processes often miss. For example, I’ve had to revisit entire device designs to ensure they accommodated the unique demands of surgeons, such as intuitive operation under time pressure and clear feedback mechanisms to confirm proper functionality amidst the chaos of the OR.
Identifying User Groups and Their Unique Needs
Identifying all your potential user groups is the first step in defining their needs. Different populations, such as adolescents and elderly users, require tailored design considerations. As I previously mentioned, adolescents may value discretion in device use, while elderly users might need ergonomic designs that compensate for reduced dexterity, to understand better the challenges faced when including adolescents in your program, check our post Pediatric and adolescent users in Human Factors.
The key point that I would like to convey is that including diverse user groups ensures that the device accommodates varying physical, cognitive, and emotional needs, leading to broader adoption and improved outcomes. In addition, you will face regulatory challenges if not all your user groups are properly represented in your medical device or combination product Human Factors program.
Key Steps in Defining User Needs for Enhanced Drug Delivery Devices
Defining user needs involves a meticulous process. While some aspects can be intuitive, it’s critical to conduct formal investigations to avoid assumptions that overlook real-world challenges. Inexperienced teams may struggle with this step, I always recommend involving experienced human factors specialists in this process since it is a foundational step in your whole usability program, it is really important to have someone that understand how a validation or summative evaluation is conducted.
Not every user need can be validated by simulated use, some of them may require clinical use validation, it is really important in this part of the process that the person defining the user needs really understand how each one of the defined needs will be validated, so they can guide you to effectively formulate each one of them.
Usually, non-experienced teams end up formulating needs in a way that cannot be validated in simulated or clinical use, and force the team to revisit all the documentation and sometimes even the design phases to accommodate new definitions.
Translating Needs into Design Inputs
Effective documentation of user needs involves breaking them down into specific requirements. For example, “the device must be easy to activate” could translate to “the device’s activation force should not exceed 2 Newtons.” Such granularity ensures that the design meets diverse user needs while adhering to the human factors regulatory requirements, to understand more the role of human factors check our post Introduction to Human Factors. Structured documentation simplifies validation, helping teams demonstrate compliance during evaluations.
One of the most impactful strategies I’ve employed is creating a visual matrix that links user needs to design inputs and tasks in your validation or summative evaluation. This approach provides a clear audit trail for regulatory submissions, but also let your team understand from the beginning how the validation will be conducted so they can easily see where and if the defined input requirement will satisfy the validation activities, reducing the risk of delays in the late phases of development.
Validation Through Human Factors Evaluations
At the end of development, summative evaluations validate that the device meets all user needs through simulated-use testing and other methodologies, ensuring compliance with the initially defined requirements. Personally, I believe that if a program is properly conducted, with sufficient formative evaluations and iterative refinements to the interface, a summative evaluation should primarily be a regulatory formality. Nevertheless, it is an essential step to confirm that the device delivers on its promises, ensuring safety, efficacy, and user satisfaction.
Simulated-use testing mimicking real-world conditions is frequently use as validation, nevertheless some needs may be better suited for validation by clinical setting, it is up to the human factors or usability expert and the clinical team to decide the best setup for validation.
Validation activities confirm that the user needs are satisfied. According to CFR 820.30: “Design validation shall ensure that devices conform to defined user needs and intended uses and shall include testing of production units under actual or simulated use conditions.” This ensures that the product not only complies with regulations but also resonates with end-users.
Conclusion
Accurately defining and implementing user needs and URS is crucial for creating effective, user-friendly drug delivery devices. By following structured methodologies and prioritizing user feedback, developers can design devices that enhance patient safety, satisfaction, and adherence. Ultimately, this approach bridges the gap between regulatory compliance and real-world usability, contributing to better outcomes for diverse populations.
