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The MHRA recently released a guidance document on the human factors aspects of design for medical devices including those in drug-device combination products. The guidance is not a compliance requirement however states that it is:
“intended for manufacturers of all device classes and developers of medical devices and drug-device combination products, and notified bodies responsible for assuring the quality of those devices. Others, such as those involved in procurement and risk management of activities involving medical devices may also find this guidance relevant to their roles. Physicians, NHS, NICE, and other stakeholders may find this guidance useful but it does not apply to them or other professionals making clinical decisions”
Human factors refers to how a person will interact with the systems surrounding them, including the technology they use and has long be part of the regulatory framework for medical device and drug-device combination product development. The CDRH originally released human factors guidance in 2000 and in 2010, Directive 2007/47/EC amended the MDD and Recital 18 provided the background to the introduction of more specific human factors requirements into the MDD: ‘As design for patient safety initiatives play an increasing role in public health policy, it is necessary to expressly set out the need to consider ergonomic design in the essential requirements. In addition, the level of training and knowledge of the user, such as in the case of a lay user, should be further emphasised within the essential requirements. The manufacturer should place particular emphasis on the consequences of misuse of the product and its adverse effects on the human body.’
In the last 17 years there have been a number of different international standards and iterations of standards describing the application of human factors to medical device development. The most recent including, IEC 62366-1:2015 Medical Devices Part: Application of usability and the 2016 version of the FDA’s Guidance document “Applying Human Factors and Usability to Medical Devices”.
The MHRA’s human factors guidance represents the first written human factors guidance from a European regulatory agency. Fortunately, the MHRA’s guidance draws heavily on the decades of medical device human factors guidance and international standards and even states at the start that its aim is to be consistent with these documents.
What is in the MHRA’s Human Factors Guidance?
For those familiar with the current medical device and human factors standards there will be very few surprises. In keeping with the aim of being consistent with the existing materials the definitions and rational are directly derived from the FDA guidance and IEC 62366-1:2015. The regulatory section of the guidance describes the human factors elements of the three EU directives and even though these are due to change in the next three years the MHRA states, “This guidance should be equally useful in supporting the demonstration of compliance with the new regulations, recognising that specific details will be updated.”
The guidance is also clear about how it should be applied to drug-device combination products:
“ for both integral and non-integral drug-device combination products, the expectations for human factors and usability engineering considerations will be similar to those for any other medical device and should be discussed in the application for a marketing authorisation and subsequent variations, where relevant”
The usability engineering process described in the guidance document is the same as the process described in IEC 62366-1:2015 and the FDA’s guidance. The guidance here clearly states that human factors is not a check-box activity.
“Depending on the risk classification of the device, the file may be requested for review by regulatory bodies and would also be useful for commissioners of devices to review in order to understand how the process has been conducted and whether their particular use scenario has been taken into account. A statement of ‘compliance with IEC 62366’ is not sufficient without supporting evidence”
As with all human factors guidance the effort should be scaled according to complexity and risks associated with the device. The guidance states, “user testing and Failure Modes and Effect Analysis (FMEA) are normally considered the minimal requirements”.
Stages of a usability engineering process
The stages of the usability engineering process include:
- Identification of uses, users, use environments, operational contexts of use and training (creation of use specification)
- Identification of known use problems
- Risk assessment of use and use error
- Formative and summative evaluation
Unlike the FDA guidance this MHRA guidance is not prescriptive where these usability studies should be carried out. Summative testing should include:
- Validation of instructions for use
- Validation of the device/system. This study must:
- Include 15 of each identified user group
- Include all tasks with identified potential use error that could impact the safety and effectiveness of the design
- Include all tasks essential for the operation of the device
- Be carried out in a realistic simulated or actual environment
- Not include prompts or request to review the manual during the study
- Assess the completion of tasks and gather subjective data on safety and ease of use.
Finally, usability engineering should be incorporated into the post-market surveillance strategy for all medical devices.