Human factors validation study of 3 mg sumatriptan autoinjector, for migraine patients

Evaluating Medical Devices Remotely: Current Methods and Potential Innovations

OBJECTIVE

We present examples of laboratory and remote studies, with a focus on studies appropriate for medical device design and evaluation. From this review and description of extant options for remote testing, we provide methods and tools to achieve research goals remotely.

BACKGROUND

The FDA mandates human factors evaluation of medical devices. Studies show similarities and differences in results collected in laboratories compared to data collected remotely in non-laboratory settings. Remote studies show promise, though many of these are behavioral studies related to cognitive or experimental psychology. Remote usability studies are rare but increasing, as technologies allow for synchronous and asynchronous data collection.

METHOD

We reviewed methods of remote evaluation of medical devices, from testing labels and instruction to usability testing and simulated use. Each method was coded for the attributes (e.g., supported media) that need consideration in usability studies.

RESULTS

We present examples of how published usability studies of medical devices could be moved to remote data collection. We also present novel systems for creating such tests, such as the use of 3D printed or virtual prototypes. Finally, we advise on targeted participant recruitment.

CONCLUSION

Remote testing will bring opportunities and challenges to the field of medical device testing. Current methods are adequate for most purposes, excepting the validation of Class III devices.

APPLICATION

The tools we provide enable the remote evaluation of medical devices. Evaluations have specific research goals, and our framework of attributes helps to select or combine tools for valid testing of medical devices.

Development and usability of a new subcutaneous auto-injector device to administer hydroxyprogesterone caproate to reduce the risk of recurrent preterm birth

Background

Current administration of hydroxyprogesterone caproate (HPC) by intramuscular injection is associated with limitations, including the potential for human error and contamination, patient anxiety, and increased risk of needlestick injury.

Objective

To describe the design of an auto-injector for subcutaneous (SC) administration of HPC and the results of studies that evaluated the target user's understanding of the proper use of this device.

Materials and methods

A single-use, prefilled, fixed-dose, disposable auto-injector intended for the SC administration of HPC was developed, and its usability by health care providers was evaluated in 3 formative (N=32, 64 injections) and 3 validation studies (N=45, 90 injections). These studies consisted of one-on-one testing sessions performed in a simulated home environment. Analyses were based on observed use error or use difficulty during the performance of specific tasks, including those considered critical (associated with high severity harms).

Results

In the formative studies, the majority of participants correctly administered an injection with the auto-injector, but prior training improved performance. Specific errors were noted, including holding the device at the injection site for a period inconsistent with its instructions for use (IFU). The IFU was modified to reduce potential occurrence of these errors. Use errors were subsequently observed on critical tasks in the first and second validation studies, including hold-time errors that were attributed to using visual cues rather than counting seconds. For the third validation study, the IFU was modified to focus on visual cues and all users were able to successfully perform the injection per the IFU.

Conclusion

An auto-injector device for SC administration of HPC for reduction in risk of recurrent preterm birth was successfully developed through iterative design and validation testing. The device design provides high usability and acceptance of this device by health care professionals.

Pen devices for self-injection: contrasting measured injection force with users' perceived ease of injection

OBJECTIVES

Past research has emphasized injection force as a clinically highly relevant technical attribute of pen devices. However, little work has been conducted to relate these results to in-use studies. This article explores whether and how differences in pen injection force profiles influence users' self-reported perceived ease of injection and preferences.

METHODS

Three different pen systems were subjected to measurements of injection force using an automated mechanical set-up followed by a simulated use study where users assessed perceived ease of injection.

MAIN OUTCOMES MEASURE

Outcomes were measured by fitting data of measured injection force and perceived ease of injection using a linear model.

RESULTS

Although mechanical testing revealed significant differences between the three pen's measured injection forces these differences were not directly perceived by users in simulated injection studies.

CONCLUSION

The article bridges literature on injection force measurement and simulated use. It reveals how users' perceived ease of injection is less sensitive to measured injection forces than prior research has assumed. Thus, future research should holistically integrate patient feedback in new device development. Key limitations of this work are the low number of participants in the simulated use study and the fact that the ease of injection was assessed indirectly.

Subcutaneous sumatriptan delivery devices: comparative ease of use and preference among migraineurs

BACKGROUND

Several sumatriptan subcutaneous autoinjector devices for acute treatment of migraine patients are available, each device differs with respect to design and features. Determining device preference and ease of use is important because patients experiencing a migraine attack are often functionally impaired.

OBJECTIVE

The objective of this human factors study was to compare migraine patients' device use performance and preferences for three sumatriptan subcutaneous autoinjectors: a disposable two-step device (Zembrace^® SymTouch^®), a disposable three-step device (Sumavel^® DosePro^®), and a multistep reloadable device (Imitrex^® STATdose^®), using simulated injections.

METHODS

Each study subject performed two unaided simulated injections with each of three different drug delivery devices, which were presented in counterbalanced order. The participants were then asked to rate the three devices on various subjective measures. The primary end point was overall device preference using a visual analog scale.

RESULTS

A total of 54 subjects participated and each subject performed two simulated injections with each of the three devices. Most subjects preferred the two-step device (88.9%) to the three-step (13.0%) and the reloadable (1.9%). The two-step device had higher mean overall preference ratings (F (2, 159)=56.6, P<0.01) and higher ratings for ease of use, intuitiveness, convenience, portability, and control. The two-step device had a first injection full-dose delivery success rate of 44.4%, higher than both the reloadable (24.1%) and the three-step (3.7%) devices. The number of errors with the two-step device (n=3) was ~90% lower than the three-step (n=49) and reloadable (n=44) devices.

CONCLUSION

In this human factors study, 54 migraineurs used simulated injections to compare three sumatriptan subcutaneous delivery devices. Zembrace SymTouch, a two-step device, was most preferred compared with Sumavel DosePro and Imitrex STATdose. It also ranked highest for ease of use and various other measures. In this study, migraine patients preferred the autoinjector that they rated as simpler and more intuitive.