Developing an ecosystem of interoperable personal, connected health devices and services is becoming increasingly important. The U.S. healthcare system is suffering from a long list of ailments, and almost half of all Americans, 133 million people, live with a chronic condition. By 2020, as the population ages, it is estimated that this number will increase to 157 million and by 2030, half the population will have one or more chronic medical conditions.1 

Managing these conditions alone accounts for health expenditures of more than $1 trillion (including direct and indirect costs) annually in the United States.2 Adding to this is a lack of access to healthcare. According to a 2005 report by Rand Health and The Communications Institute, nearly 45 million Americans are uninsured and American adults receive just half of recommended health care services.3 

Furthermore, healthcare personnel shortages are affecting both specialty and primary medical care. By 2015, according to the Association of American Medical Colleges (AAMC), there will be a deficit of 62,900 physicians in the United States, and in 2025, the AAMC projects a deficit of more than 130,000 physicians across all specialties.

Some self-insured employers are instituting negative incentives to employees who make lifestyle choices that put their health at risk,4 with a message that amounts to “get healthy or pay,” thereby putting health self-management on the front burner for their employees. Financing trends such as pay-for-performance and accountable care organizations may influence providers to seek more efficient and effective means of caring for their costliest patients.5 

There are indications, however, that the connected mobile health (mHealth) market is growing. The global mHealth applications market is expected to grow at a compound annual growth rate (CAGR) of 24 percent from 2010 to 2014, according to research by Technavio.6 In addition, business market research firm MarketsandMarkets predicts the global healthcare IT market will reach $162.2 billion in 2015, a 10.2 percent CAGR from the 2010 value of $99.6 billion.7 

Financing trends such as pay-for-performance and accountable care organizations may influence providers to seek more efficient and effective means of caring for their costliest patients.

For the foreseeable future, providers, government, private payers, and patients all have reason to adopt connected health technologies. But if connected health is to become fully integrated into health self-management and healthcare delivery, the industry must commit to interoperability.

Evidence from studies of remote monitoring and other areas of connected health suggests that connectivity between technologies may contribute to improved clinical outcomes.

The argument in favor of interoperability is easily understood if one looks to the mobile phone market, where introduction of interoperability at a global scale for voice, data, and equipment fueled growth from one million connections in 1994 to six billion by the end of 2011.8 

Interoperability facilitates consolidation and analysis of patient health data from various telehealth devices and services, for the purposes of improving personal health and healthcare delivery. Without it, some of the value of personal data is lost.

Perhaps the strongest argument for interoperability is that it has the potential to create and develop a market of technologies made for “plug and play” integration into connected systems for consumer health self-management and healthcare delivery.

In this article, we discuss the case for interoperability, and the specific example of Continua's Design Guidelines for device manufacturers, developed to facilitate an ecosystem of connected personal health and fitness products and services.

Evidence from studies of remote monitoring and other areas of connected health suggests that connectivity between technologies may contribute to improved clinical outcomes. For example, Geisinger Health Plan's IVR (Interactive Voice Response) post-hospital discharge telemonitoring solution, used as an adjunct to case management, and its other telemonitoring solutions, demonstrated a 44% reduction in 30-day hospital readmissions, with a patient compliance rate exceeding 85%.

In a press release about the program, Geisinger affirmed its belief that the reduction in re-admissions reflects improved outcomes. Jim Peters, system vice president and head of strategic industry partnering activities at Geisinger Health System was quoted as saying, “our success in leveraging AMC Health's technology to reduce readmissions underscores our belief that providing clinicians with the right data, at the right time, to drive the right interventions is critical to driving the best patient outcomes.”9 

The Whole System Demonstrator Programme, undertaken by the U.K.'s Department of Health, was “the largest randomized control trial of teleHealth and telecare in the world, involving 6,191 patients and 238 general practices.”10 Of those, 3,154 patients from 177 practices were included in the analysis.11 

According to the U.K. Department of Health:

“The early indications show that if used correctly, teleHealth can deliver a 15% reduction in A&E visits, a 20% reduction in emergency admissions, a 14% reduction in elective admissions, a 14% reduction in bed days and an 8% reduction in tariff costs. More strikingly they also demonstrate a 45% reduction in mortality rates.”12 

However, given a trial period of 12 months (on a patient basis), whether or not these results would persist over the long term is an unanswered question.

Support for connected health is not limited to remote monitoring nor to devices historically used for health management: In March 2012, researchers from the Stanford Prevention Research Center reported that smartphone applications can raise awareness and motivate older adults to improve their health.

After eight weeks, 80% of participants reported increased awareness regarding the targeted health behavior (increased walking, decreased sitting time, improved diet), and three-quarters said the apps helped track the behavior. Two-thirds of the participants indicated the apps increased their motivation to make improvements.13 

Social media also shows promise for connected health management: In 2009, the Archives of Dermatology published a patient survey conducted by the Center for Connected Health, a division of Partners HealthCare, which recruited 260 patients from five online psoriasis support groups. The survey revealed that online support communities and social networks appear to benefit patients with psoriasis.

Nearly half of all study participants reported improvements in their quality of life (49.5%) and psoriasis severity (41%) after joining the site. Key factors reported with use of online support sites included availability of resources (95.3%), convenience (94%), and the lack of embarrassment when dealing with personal issues (90.8%).

Data from remote monitoring, smartphone apps, and social media studies collectively suggest that connected health could have a positive impact on healthcare. However, as the field is relatively young, detailed studies to assess clinical impact of connectivity to other sensors and/or electronic health records (EHR) are needed to accurately determine the effects of remote patient monitoring.

While direct data demonstrating the positive impact of interoperable personal connected health on improved workflow efficiency is lacking, acknowledgement of its workflow-related benefits exists.

In its 2008 report, Health Care at the Crossroads: Guiding Principles for the Development of the Hospital of the Future, the Joint Commission concludes, that:

“while health care policymakers and standards bodies hammer out solutions for achieving interoperability of systems that will allow for data sharing between separate entities, many health care providers see this as a reason to wait to invest in HIT (health information technology).

Unsolved issues around data privacy and fear of system obsolescence further fuel their hesitancy. In the meantime, lack of interoperability between HIT systems and medical devices that have an HIT component—such as hospital beds that take readings of vital signs but do not integrate with the EHR—slow the workflow of care providers.”

While it remains to be seen whether workflow efficiencies are a byproduct of adopting interoperable connected health technologies, some healthcare systems continue to embrace them. Geisinger, for example, expanded its teleHealth programs to include hypertension and diabetes patients.

Similarly, the Center for Connected Health's Connected Cardiac Care home telemonitoring and education program, which began as a pilot for patients with heart failure, was adopted as an “opt-out” program for this patient population, patients are now automatically enrolled in the program and must choose to opt out.

At the implementation stage, interoperability may offer advantages, as illustrated by a connected health program to aid victims of the Great East Japan Earthquake. The Disaster Cardiovascular Prevent Network (D-CAP) was developed to remotely monitor the blood pressure of evacuees, using personal health records and multiple devices to provide timely advice to medical staff on disaster sites and identify high-risk evacuees immediately following the earthquake.

Interoperability was pre-existing since technologies used in the program, supplied by A&D Medical, Alive Inc., Ryoto Electro Corp, Panasonic, Toppan Forms, and Intel, were already certified. Thus, D-CAP was not restricted to or reliant on a single supplier of devices.

While it remains to be seen whether workflow efficiencies are a byproduct of adopting interoperable connected health technologies, some healthcare systems continue to embrace them.

This alleviated supply and compatibility issues for integrating devices on-site, as certified devices are guaranteed to plug and play, that is, work “out of the box.” The medical support team was ready in one week, and A&D credits the program with avoiding loss of life, stating in its program summary that “compatibility and interoperability of instruments are of primary importance.”

However, it is important to note that in this case, a single parameter, via blood pressure sensors from multiple patients was transmitted to a compatible receiving station. Further studies are needed with more parameters.

In an as yet unpublished study, Continua conducted a series of interviews with companies that have certified a product for interoperability. Among the responses, participants cited two strong reasons to build for interoperability: time and money.

Decreased design costs for communication functionality saved an estimated $40,000 to $80,000 per device.

Decreased design costs for communication functionality saved an estimated $40,000 to $80,000 per device. Additionally, integration time was reduced from 12 to three weeks, facilitating a faster product launch.

Participants also perceived a smoother regulatory approval due to improved reliability and security of products and believe that reduced barrier to entry will foster competition and lower prices, driving more rapid adoption.

To address connectivity in the market for connected health devices and services, the majority of manufacturers develop communication functionality for their devices in-house. A systems integrator is then responsible for implementing connectivity within a specific connected health system. This practice preserves reliance on specific components within a system, which may impede the growth of an interoperable device ecosystem that has potential to spur innovation and adoption of connected health.

Continua has taken the approach of publishing standards-based interoperability guidelines. It works with existing Standards Developing Organizations (SDOs) such as the Institute of Electrical and Electronics Engineers (IEEE), to facilitate connections between the different components of a personal teleHealth system.

Building devices for interoperability will ideally facilitate integration into teleHealth systems and reduce the complication of switching suppliers within a teleHealth system. This is likely to create increased competition with economies of scale, putting price pressure on connected health components, and reducing the margins for all players. In an interoperable market, device manufacturers and system integrators will focus their efforts around the areas where they add most value.

In an interoperable market, device manufacturers and system integrators will focus their efforts around the areas where they add most value.

As mHealth interoperability is in the earlier stages of development, we analyze here one example of guidelines development, that of Continua. The guidelines are published in the first quarter every year, and in general, represent a year or more of development from use case definition to certification-ready guidelines.

Use cases, which describe the functionality and components of a personal teleHealth system, are submitted by Continua members and analyzed to identify interoperability needs. SDO standards are then selected against these use cases, for their ability to meet these requirements.

Where a gap is identified between the requirements and the available standard, Continua works with the SDO to resolve or, in some instances, define additional guidelines to address the gap. Where it exists, optionality is removed in order to facilitate an interoperable end-to-end solution.

Reference architecture (Figure 1), defines the various types of components of a personal teleHealth system and how they can be connected, and defines the interfaces.

Figure 1.

Reference Architecture for Continua Example

Figure 1.

Reference Architecture for Continua Example

Close modal

The Continua example of interoperability architecture (Figure 1) comprises three types of connections between sensors and application hosting devices, or AHD:

  • Personal Area Network (PAN)

    The PAN is intended for connecting sensors that are in the near vicinity of an AHD and are often mobile.

  • Local Area Network (LAN)

    The LAN is intended for connection sensors in a home or living facility to an AHD, and these sensors are often stationary.

  • Touch Area Network (TAN)

    The TAN, to be incorporated in Continua's 2013 Guidelines, is intended to connect sensors to an AHD by bringing them very close together (a few centimetres), mainly for sensors that do not need a regular connection via pairing with an AHD.

There are selected standards for two different layers of these interfaces; the transport layer and the data layer. The transport layer incorporates the following standards.

  • PAN: Bluetooth health device profile, Bluetooth Smart (currently support a subset of devices) and Universal Serial Bus (USB) personal healthcare devices.

  • LAN: ZigBee healthcare profile (note that the LAN/WAN categories presented here are not necessarily those used by other organizations).

  • TAN: Near field communication, or NFC, to be added to 2013 Guidelines as part of the TAN interface.

For the data layer, the guidelines comprise the International Organization for Standardization (ISO)/IEEE 11073 personal health device family of standards. The guidelines are not intended to address regulation. Instead each organization in the Continua model engages with regulatory agencies directly on issues related to interoperability in connected health.

A variety of personal health devices can be supported, including personal emergency response system sensors, pulse oximeters, and glucose meters. Many of these devices need to work within existing regulated scenarios. Depending on the intended use of a particular set of devices, there may be a regulatory requirement for evidence demonstrating that the device set provides a safe and effective way to work within the intended use.

The WAN interface describes the connection between AHDs and back-end services (WAN devices), which enable the communication of data from an individual's devices (mobile phone, tablet, PC, set-top box) to a health service that can act on that data (weight loss service, disease management service). The interface can also be used for sensors directly connected to the internet, such as Wi-Fi enabled weighing scales or sensors with cellular connectivity embedded into the device.

Selection of standards for transport and data layers to transmit health data from the home setting to health services has occurred in close relationship with the Integrating the Healthcare Enterprise (IHE) organization, which traditionally focuses on interoperability in a clinical setting.

The transport portion of the defined WAN Interface is based on a set of web service standards defined by the Internet Engineering Task Force or IETF, World Wide Web Consortium or W3C, and the Organization for the Advancement of Structured Information Standards or OASIS, as profiled by the IHE IT infrastructure technical framework and the WS-I basic security profile.

A variety of personal health devices can be supported, including personal emergency response system sensors, pulse oximeters, and glucose meters.

The payload or data layer portion of the interface is based on the PCD-01 transaction of the device enterprise communication (DEC) profile by IHE PCD. It uses Health Level 7 (HL7) V2.6 messaging and the IEEE 11073 nomenclatures, including nomenclature extensions that support personal health devices.

The interface, built using industry standard security methods, ideally creates an end-to-end secure and reliable connection to exchange medical data, and incorporates the ability for patients to specify consent policies related to their health data.

It is anticipated that certifications from solutions with radio cellular transports in the WAN layer will increase with the emerging prominence of mobile health.

Work is in progress for the WAN interface to include extensions that support new use cases such as interactive questionnaires, video conferencing, and remote device management; as well as to make it easier to integrate the defined interfaces into mobile platforms and present standardized data for mobile applications that use consumer-focused web technologies.

The Health Reporting Network (HRN) interface describes the connection between back-end services (WAN devices), such as weight loss services and disease management services, and electronic/personal health records (HRN devices). When in use, back-end services are often under control of different companies and tend to focus on a specific aspect of an individual's healthcare needs, often in customized implementations that preclude interoperability.

Traditionally, EHR reside within a hospital repository and are accessible to doctors, but not patients. However, current trend is to allow patients access to data stored in EHR through a patient portal.

At the same time, PHR initiatives such as Microsoft HealthVault allow patients to gather, store, and exert full control over their own data. The HRN interface ideally enables sharing of health data available from personal teleHealth back-end services to EHR and PHR systems by specifying the necessary criteria to enable this.

The IHE cross-enterprise document reliable interchange (XDR) and cross-enterprise document media interchange (XDM) profiles have been selected as the means to establish communication between WAN devices and EHR/PHR systems. On top of this profile, the HL7 personal health monitoring report document format was chosen to ensure consistent data encoding.

Over 70 devices have completed certification testing in the Continua system. Certified devices cover the spectrum from sensors to AHDs, and back-end services to electronic health records. Presently, connectivity between a sensor and AHD can be achieved via Bluetooth, Bluetooth Low Energy, Zigbee, or USB (with NFC coming soon); while data between AHD, teleHealth service centers, and back-end services can shared over any IP connection, such as cable, ADSL, Wi-Fi, or cellular.

Certified devices cover all three certifiable transports, Bluetooth, USB, and Zigbee,14 and further development of the certification program to extend certifiable transports is under way. Transport layer testing ensures data messages can be shared once a communication channel has been established.

According to a May 2012 Continua membership survey, PAN and LAN devices continue to be the primary certification drivers, at 71%. Bluetooth is the main transport of choice, followed by Zigbee and USB. A handful of devices implementing Bluetooth Smart and NFC are also in the pipeline.

It is important to work collaboratively towards interoperability, and Continua established liaison agreements with a number of industry special interest groups (SIG),15 which host joint testing events, coordinate test platform development, and may participate in certification program development.

Devices implementing Bluetooth HDP, USB PHDC, and Zigbee HCP are required by Continua to have transport certification from the respective SIG. Certification requirements for Bluetooth Smart and NFC devices are still in development.

It is anticipated that certifications from solutions with radio cellular transports in the WAN layer will increase with the emerging prominence of mobile health. Continua has begun work to leverage certification programs established by the CDMA Certification Forum, Global Certification Forum, and PCS-1900 Type Certification Review Board or PTCRB, which define requirements to ensure compliance with the 3GPP or 3GPP2 cellular network standards within the mobile operators' networks.

In conclusion, an opportunity exists for device manufacturers to enter the market for personal connected health. Pressures are mounting on the U.S. healthcare system, creating urgent incentives for change. While workflow efficiency data are lacking, initial evidence suggests that connected health technologies can improve the quality and efficiency of clinical care.

Furthermore, companies certifying connected health devices and services for interoperability are showing early indications of time and cost savings. Standards and guidelines for interoperability of personal connected health devices are necessary to fulfill the potential for a technology-enhanced system for healthcare delivery and personal health management.

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About the Authors

Ian Hay is head of Emerging Technologies at Orange, and chair of the Technical Working Group and Guidelines Control Board at Continua Health Alliance. E-mail:

Kelvin Lim, MBA, is senior R&D engineer at Roche Diagnostics, Indianapolis, IN; and chair of the test and certification work group at Continua Health Alliance. E-mail:

Frank Wartena, MSc, is senior scientist at Philips Research Europe and vice-chair of the Technical Working Group at Continua Health Alliance. E-mail: