Innovations in medical sensors

According to data from the Centers for Medicare and Medicaid Services (CMS), the United States spent 13.6 trillion dollars on health care in 2018, with annual increases trending at 4.6 per cent (Lehr, 2013). Concerns over burgeoning healthcare expenditures have increased pressure on healthcare providers and payers to reduce overall costs through a variety of approaches, including increasing focus on the development of novel rapid diagnostics for both point of care (POC) testing by healthcare professionals and in home use by patients (Elder, 2012; Lehr, 2013). Although testing with POC diagnostics is generally more expensive than testing in a clinical laboratory on a cost-per-test basis, it is anticipated that the use of rapid diagnostics provides offsetting advantages. For example, continuous monitoring of a chronic medical condition will enable better patient involvement and capture ongoing patient-specific data, which can lead to improved patient care, thus reducing incidents requiring physician intervention, including emergency room visits and hospital admissions.

A more rigorous analysis of the value proposition for diagnostics information as a component in the healthcare ecosystem was recently reviewed by Wurcel et al. (2019). The authors discuss the ongoing struggle that governments face to balance sustainable health care spending against the goal of high-quality health care, pointing out that the impact of diagnostics information has not typically been analysed with the same rigour as direct medical interventions. They highlight the value of readily accessible diagnostics information for patients—empowerment and knowing/deciding—as well as for healthcare professionals and payers who can evaluate the impact of diagnostics on healthcare system management and outcomes.

Increasingly, one of the drivers of the POC diagnostics market is the growing number of older adults, who not only require proportionately greater amounts of health care but also expect more rapid medical results as well as short turnaround times (Elder, 2012; Lehr, 2013). The National Institute of Aging expects there to be nearly one billion individuals over the age of 65 in the year 2030 (Lehr, 2013). The number of individuals with chronic diseases such as hypertension, diabetes and chronic kidney disease is anticipated to increase globally, with a surge in global diabetes that is already staggering. These trends will be exacerbated by a shortage of skilled healthcare workers, both in the developing and developed world, reducing the number of healthcare providers available to perform conventional hospital- or clinic-based diagnostic procedures.

Despite the attractiveness of the market for POC diagnostics, developers must overcome multiple technical, regulatory and reimbursement challenges to successfully introduce a novel product. Considerations when commercializing a point of care diagnostic include acceptability by the end-user, regulatory burden, convenience, simplicity in use, simplicity in data interpretation, price, portability (e.g. capability for in home use) and reimbursement (Elder, 2012; Lehr, 2013). Getting older adults to adopt innovative mobile health technologies in general and innovative sensor technology in particular requires engagement with the community. Adams recently noted that older adults have adopted mobile phones and computers at high rates but have not adopted digital health technology at a similarly high rate (Adams; Levine, Lipsitz, & Linder, 2016). He noted that many wearable medical devices are not designed with ageing adults in mind. Older adults often have differences in hearing, mobility and/or vision that preclude the use of devices with complicated interfaces and small-scale components. In addition, older adults with chronic conditions such as Parkinson's disease or diabetes may have physical changes (e.g. rigidity and tremors, or loss of sight) that affect the use of small-scale devices. Devices that are popular with older adults (e.g. Life Alert Emergency Response devices) have straightforward interfaces and automated features.

From an engineering design consideration, medical device development is an iterative process that must involve collaboration among older adults, caregivers, healthcare providers and medical device engineers (Baig, GholamHosseini, Moqeem, Mirza, & Lindén, 2017) in order to be successful. Michard, Pinsky, and Vincent (2017) created the acronym NEWS to describe desirable features from the medical device engineer perspective for new types of cardiac monitoring devices: “N” for non-invasive, “E” for easy to use, “W” for wearable and wireless, and “S” for smart algorithms and smart software.

At present, there is no globally harmonized regulatory pathway available for developers to seek market authorization for a novel diagnostic based on a single international regulatory filing. Thus, manufacturers must interact directly with individual regulatory authorities and multiple registration requirements in different countries and regions (such as the European Union) to bring products to market. In the US, all commercially manufactured In Vitro Diagnostics (IVDs) are regulated as medical devices by the US Food and Drug Administration (FDA). As such, all novel IVDs are subject to either 510(k) or PreMarket Approval (PMA) review by FDA prior to commercialization, and all IVD manufacturing facilities are inspected by the FDA. While diagnostics manufacturers face rigorous scrutiny from the US FDA, it is worth noting that the FDA's Center for Devices and Radiologic Health (CDRH), under the direction of Dr. Jeffrey Shuren, has implemented a number of regulatory initiatives aimed at fostering medical device innovation, including the Breakthrough Devices Program, the Digital Health Pre-Certification Pilot and the Payor Communication Task Force. As diagnostics regulation in the US has evolved, requirements for laboratory usage of IVDs, including so-called laboratory-developed tests (LDTs), and clinical laboratory operations fall under CMS according to the Clinical Laboratory Improvement Amendments (CLIA). One positive outcome of this parallel regulation of IVDs has been the CLIA waiver process, which allows some well established IVDs to be used by less skilled users, including patients at home. Several categories of blood analysis POC diagnostics are approved by the FDA and CLIA waived for home use, including tests for monitoring triglycerides, cholesterol, alcohol, blood urea nitrogen, lactate, ketones, amines, thyroid-stimulating hormone and blood glucose (Elder, 2012; Lehr, 2013).

There are also significant hurdles to obtaining payment coverage by government and private insurers, as well as pressures to minimize the cost associated with usage of POC testing (Elder, 2012; Lehr, 2013). The use of diagnosis-related groups (DRGs) incentivizes physicians to minimize the costs associated with diagnostic testing. Even now, CMS does not cover payment for several types of routine tests. Convincing the decision-makers at these agencies that the device will provide improved outcomes and higher quality of life will be an important consideration in the development of a new sensor. Although private third-party payers may cover a significant portion of diagnostic testing costs, they often follow the lead of CMS and must often be engaged individually regarding coverage for a particular diagnostic.

Despite the challenges, there are various examples of successful diagnostics development, both in terms of healthcare system impact as well as successful application of design iteration principles. In the first instance, continuous glucose monitoring (CGM) devices, initially developed for use in type 1 diabetics, have now been successfully expanded to use in type 2 diabetics, with the evolution of the technology spanning almost two decades from the first FDA CGM approval in 1999 for professional use only to the 2017 CMS coverage of ‘therapeutic CGMS’ for use by type 2 diabetics meeting defined criteria (Welsh & Thomas, March, 2019). As CGM technology improves and usage increases, it is likely to have a favourable impact on patients and diabetes treatment costs, which are currently estimated at $237 billion annually in the US (Kompala & Neinstein, 2019).

A recent example of successful application of an iterative design process to a novel sensor was described by Christina Wolf, who received a James Dyson award for a home monitoring device to stimulate breathing of a newborn via vibration or to sound an alarm when heart rate, respiration or oxygen levels deviated beyond normal values. She began by defining the stakeholders associated with neonatal medical devices as neonates, parents, neonatologists, nursing staff, medical device distributors and importantly for potential reimbursement considerations, health insurance providers. Engaging these stakeholders provided critical insights into concerns about potential device designs and product usage, differing levels of comfort with technical aspects of potential designs and valuable feedback regarding best case product usage. Key learnings that were incorporated into device design included the need for reliability, durability, ease of use and unobtrusive operation.

Going forward, technology and design advancements, such as the innovations described in this journal, will enable more comprehensive and more rapid POC testing. It is hoped that these innovations will result in more rapid decision making and better patient outcomes for patients of all ages. Undoubtedly, continued innovations in diagnostic testing will take on ever-increasing importance and urgency against the backdrop of the ongoing SARS-CoV-2 pandemic and an increasingly strained global healthcare ecosystem.