The Evolving Landscape of Wearable Devices: From Wellness to Medical Devices

Introduction?

The landscape of wearable technology is rapidly evolving, with a significant shift in the transition from general wellness devices to those with medical applications. This article examines this transition's regulatory and business implications, focusing on off-the-shelf devices such as smartphones, smartwatches, fitness bands, and smart rings.

The wearable medical device market is experiencing substantial growth. According to recent market research, the global wearable medical device market size is projected to expand from USD 41.75 billion in 2024 to USD 86.2 billion by 2029, growing at a CAGR of 15.6% from 2024 to 2029 (figure 1).?

?Figure 1: Wearable medical device market.?

The clinical possibilities of wearable medical devices are extensive and continually expanding. These devices are playing a crucial role in various healthcare applications, including:?

Cardiac Health Monitoring?

Comprehensive heart health tracking through continuous heart rate monitoring, ECG recording, atrial fibrillation detection, and blood pressure estimation using smartwatches, fitness bands, and smart rings. Examples include:?

• 苹果 Watch: Offers ECG functionality and irregular heart rhythm notifications?

• Fitbit Health devices: Provide continuous heart rate monitoring and can detect atrial fibrillation?

• Withings : Offers blood pressure monitors and ECG-capable smartwatches?

• B-Secur : Develop ECG monitoring technology for various wearable devices?

Sleep Analysis and Disorders Detection?

Advanced sleep health assessment including sleep stage tracking, sleep apnea risk evaluation, circadian rhythm analysis, and insomnia pattern detection using smartwatches, rings, and smartphone apps. Companies in this space include:?

• ōURA Ring: Provides detailed sleep analysis and tracks various sleep stages?

• Fitbit Health: Offers sleep tracking features in its smartwatches and fitness trackers?

• Wellue : Develops the O2Ring, which continuously tracks oxygen levels and heart rate during sleep?

Neurological Health Assessment?

Monitoring of neurological conditions through tremor and movement tracking, seizure detection and prediction, cognitive function testing, and gait analysis using smartphone and smartwatch sensors. Notable examples include:?

• Cala Health : Offers the Cala Trio, a wrist-worn device for reducing hand tremors in patients with neurological conditions?

• 苹果 Watch: Includes fall detection and movement disorder tracking features?

• BioSensics : Develops wearable sensors for gait analysis and fall risk assessment?

Women's Health Tracking?

Specialized women's health monitoring including menstrual cycle tracking, fertility prediction, pregnancy monitoring, and menopause symptom management using smartphone apps integrated with wearable devices. Companies in this field include:?

• Fitbit Health: Offers menstrual health tracking features in its devices and app?

• 苹果 : Provides cycle tracking functionality in the Apple Watch and Health app?

• Identifyher: Develops wearable devices specifically for women's health monitoring?

These examples demonstrate the diverse applications of wearable medical devices across various aspects of healthcare, showcasing the potential for improved patient care and proactive health management.?

Figure 2: Wearable medical device clinical applications?

The wellness movement has gained substantial traction, with consumers increasingly utilizing these devices to collect personal health data. The critical question now facing the industry is: At what point does this data transition from general wellness information to medically actionable insights??

Several prominent companies, including 苹果 , WHOOP and Fitbit, have successfully navigated the transition from general wellness to medical device status. It is crucial to understand that this transition is not determined by the hardware or data itself but by the intended use of the product. As such, the number of “wearable” devices approved and cleared by the FDA is hard to determine – the category includes a wide range of devices (e.g. glucose monitor devices and breast pumps) that do not fit with the common use of the term “wearable” in the wider world. As such it is important to note that not all wearable devices claiming medical capabilities are FDA-authorized. In fact, on February 21, 2024, the FDA issued a safety communication warning consumers against using smartwatches or smart rings that claim to measure blood glucose levels without piercing the skin, as these devices have not been authorized, cleared, or approved by the FDA for this purpose.?

Regulatory Framework and Product Classification?

Intended Use: The Defining Factor?

The regulatory classification of a wearable device hinges on its "Intended Use." This concept is fundamental in determining whether a product falls under medical device regulations. When a device's intended use involves informing medical decision-making, the manufacturer must demonstrate to regulatory bodies, such as the FDA, that the device meets stringent accuracy and reliability standards.?

It is noteworthy that companies successfully making this transition often control both the hardware and software components of their devices. This vertical integration appears to be instrumental in achieving the level of accuracy and reliability required for medical devices.?

Regulatory Landscape?

United States?

General Wellness Devices?

The FDA has established guidelines for general wellness devices (figure 3), which are predicated on the principle that promoting healthy lifestyle choices can positively impact health outcomes. These devices typically focus on:?

• Sleep quality improvement?

• Physical activity tracking?

• Weight management?

Key characteristics of general wellness devices include:?

• Exemption from FDA regulation?

• Low risk to user safety?

• General health and wellness claims?

• No specific disease diagnosis, treatment, or cure claims?

The FDA's guidance document "General Wellness: Policy for Low-Risk Devices.?" provides comprehensive information on this category.?

Figure 3: General Wellness, Policy for Low-Risk Devices?by the FDA

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Medical Devices?

When a wearable crosses into medical device territory by making specific medical claims or being used for medical decision-making, it falls under FDA oversight and is classified based on risk.??

Medical Device Classification (Figure 4):?

Class I: Low risk, general controls?

• Least regulatory control?

• Most exempt from premarket notification?
• Examples: Basic fitness tracking apps with medical intended use.?

Class II: Moderate risk, special controls?

• Require 510(k) or DeNovo premarket review?

• May need clinical data to support claims?
• Examples: Apple Watch ECG app, Fitbit's atrial fibrillation detection feature, AliveCor's KardiaMobile ECG device?

Class III: High-risk, premarket approval??

• Require clinical trials and premarket approval?

• Highest level of regulatory control?
• Examples: Currently, there are no Class III wearable phone/watch devices, as this category is reserved for high-risk, implantable, or life-sustaining devices

Figure 4: FDA Medical Device Classification?

Note that most consumer wearables fall into Class I or Class II categories. The classification determines the regulatory pathway and requirements for bringing the device to market, with increasing scrutiny and evidence needed as the risk level increases.?

European Union?

In the European Union, the Medical Device Regulation (MDR) 2017/745 governs the classification and regulation of medical devices, including wearables with medical claims.? The MDR provides a risk-based classification system (Class I, IIa, IIb, or III) that determines the level of regulatory scrutiny applied to a device.?

Manufacturers of medical wearables must undergo conformity assessments, often involving Notified Bodies, to ensure compliance with safety and performance standards before affixing the CE mark, which permits market access within the EU.??

Conversely, wearable devices without medical functions—such as fitness trackers or smartwatches intended solely for general wellness or lifestyle purposes—are not subject to the MDR. Instead, these consumer wearables fall under the General Product Safety Directive (GPSD) 2001/95/EC, which mandates that products placed on the market are safe for consumer use. Manufacturers must ensure their products meet relevant safety standards and provide appropriate instructions and warnings to users. While the GPSD does not require conformity assessments by Notified Bodies, manufacturers are responsible for conducting internal assessments to verify product safety.??

Case Studies?

Apple Watch ECG Feature

In 2018, Apple obtained FDA DeNovo clearance for its ECG app on the Apple Watch Series 4 and subsequent models (figure 5). This feature enables users to record an electrocardiogram from their wrist, potentially identifying atrial fibrillation. The FDA's review process included data from a clinical trial with approximately 600 participants, demonstrating the app's efficacy in detecting atrial fibrillation. The agency classified it as a Class II medical device, acknowledging its moderate risk profile and implementing special controls to ensure safety and effectiveness.?

Figure 5: Apple Watch App and iPhone App components of the ECG App device

Following the initial approval, Apple continued to develop its health platform by including new features including:?

• Irregular Rhythm Notification Feature (IRNF): This feature monitors heart rhythms in the background and alerts users to irregular patterns suggestive of AFib. The IRNF received FDA clearance on October 22, 2021 (K212516).

• Atrial Fibrillation History Feature: Cleared on June 3, 2022 (K213971), this feature enables users to track the frequency and duration of AFib episodes over time, providing valuable information for managing the condition.?

• Sleep Apnea Notification Feature (SANF): Approved on September 13, 2024 (K240929), the SANF monitors sleep patterns to detect signs of sleep apnea, alerting users to potential breathing disruptions during sleep.? Note the Indication for use: The Sleep Apnea Notification Feature (SANF) is a software-only mobile medical application that analyzes Apple Watch sensor data to identify patterns of breathing disturbances suggestive of moderate-to-severe sleep apnea and provides a notification to the user. This feature is intended for over-the-counter (OTC) use by adults aged 18 and over who have not previously received a sleep apnea diagnosis and is not intended to diagnose, treat, or aid in the management of sleep apnea. The absence of a notification is not intended to indicate the absence of sleep apnea.?

Fitbit's Atrial Fibrillation Detection?

Fitbit received FDA clearance in 2022 for its photoplethysmography (PPG) algorithm designed to identify atrial fibrillation. The company now provides two FDA-approved methods for atrial fibrillation detection:

1. The ECG app: This allows users to take a spot-check approach by proactively screening themselves for possible AFib and recording an ECG trace that can be reviewed with a healthcare provider.
2. The PPG-based algorithm: This enables long-term heart rhythm assessment, helping to identify asymptomatic AFib that might otherwise go undetected. The algorithm passively assesses heart rhythm in the background while the user is still asleep.

This feature utilizes the optical heart-rate sensor on Fitbit devices to assess heart rhythm during periods of stillness or sleep. The company conducted the Fitbit Heart Study, a large-scale clinical trial enrolling over 455,000 participants. The study demonstrated that the Fitbit PPG detections correctly identified atrial fibrillation episodes with 98% accuracy. These two methods provide users with comprehensive options for monitoring their heart health and detecting potential atrial fibrillation episodes.

Figure 6: Fitbit's Atrial Fibrillation Detection Methods

Regulatory Strategy and Submissions?

Fitbit's regulatory strategy involved a multi-pronged approach to obtain clearance for both PPG and ECG-based atrial fibrillation detection methods. The company first received FDA clearance for its ECG app in 2020, which allows users to take spot-check measurements. For the PPG-based algorithm, Fitbit submitted data from the Fitbit Heart Study to the FDA, leading to its clearance in 2022. This strategy aimed to provide users with both long-term and short-term AFib assessment options. Fitbit's submissions to regulatory agencies included clinical trial data demonstrating the algorithm's high sensitivity (98.7%) and specificity (100%) in detecting AFib. The company also sought regulatory approvals in Europe, indicating a global approach to bringing these features to market?

Legal and Ethical Considerations?

The convergence of wellness and medical applications in wearable devices presents several significant legal and ethical considerations:?

1. Data Privacy and Security: The collection of sensitive health data necessitates robust data protection measures, compliant with regulations such as HIPAA in the US and GDPR in the EU.?
2. Liability: As wearables increasingly inform medical decisions, questions of liability in cases of device failure or misdiagnosis become more complex.?
3. Informed Consent: Clear communication of device capabilities and limitations to users is crucial, particularly for devices with medical applications.?
4. Health Equity: Ensuring equitable performance across diverse populations is essential, as concerns have been raised about the accuracy of some wearable technologies across different skin tones and body types.??
5. Regulatory Compliance: As companies expand their product offerings to include more medical features, they must navigate increasingly complex regulatory landscapes, which can vary significantly between jurisdictions.?

Conclusion?

The blurring line between wellness devices and medical devices presents both opportunities and challenges for the wearable technology industry. As this field evolves, collaboration between industry leaders, healthcare providers, and regulatory bodies is crucial to ensure the safe, effective, and appropriate use of these devices.?

As wearable technology continues to advance, it is poised to revolutionize healthcare delivery, enabling more personalized, proactive, and data-driven approaches to patient care and disease management. The future of wearable technology in healthcare is promising, but it requires careful navigation of the complex intersection of technology, medicine, and regulation. Companies operating in this space must remain vigilant in their compliance efforts and proactive in addressing the ethical considerations associated with their products.?

Stay tuned for upcoming editions of 'Innovation Meets Regulation,' where we explore the intersection of healthcare innovation and regulatory frameworks that shape the industry's future.

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