| Apple, meanwhile, does not display blood pressure readings in its FDA-authorized feature. The Apple Watch analyzes 30 days of data and alerts users of possible hypertension. The company’s data shows the feature catches just 41% of cases. Since the release of Apple’s product last fall, there’s been an outcry from experts concerned that it might result in false reassurance for the 59% of people who have hypertension and aren’t flagged. This concern extends to devices that display blood pressure values of questionable accuracy as well. Someone could falsely believe their numbers are healthy and not seek medical care. Though products might specify that they are not intended to diagnose or rule out medical conditions, users still may lean on readings inappropriately. “As a consumer there’s going to be a very low level of literacy in understanding how the technologies work and whether the output is accurate or not,” said Eugene Yang, a cardiologist and professor at the University of Washington who studies cuffless technology. He added, “If something is put on the market, then [consumers] come in probably with some assumptions that this has been tested appropriately.” If they didn’t believe that, why would they purchase a device? Contributing to consumer confusion is the lack of rules or norms around how companies should disclose information about the function of wellness features and their performance. The FDA’s wellness guidance does instruct companies not to display physiologic measurements like blood pressure that “mimic those used clinically,” unless they are “validated.” During a February presentation on the new guidance, an FDA official said that “there are no specific requirements for validation” and that it could include manufacturer testing or peer-reviewed studies. The official said that “FDA encourages making validation results public” and that the agency may ask manufacturers for data. The validation requirement has created some confusion in industry about what exactly needs to be done. David Simon, an associate professor at Northeastern University School of Law, called the mandate “quasi-regulatory” — something the FDA could enforce if it sees the need but which otherwise offers just a guideline for manufacturers to follow. One obstacle, industry insiders say, is that there is currently no International Organization for Standardization protocol for validating cuffless blood pressure wearables. Many manufacturers, including Samsung, have chosen to rely on modified protocols for cuffed devices, which are tested on seated, relaxed users. An ISO protocol for cuffless blood pressure monitoring that takes into account more complex conditions has been drafted but not finalized and disseminated. Despite FDA’s nudging, companies have disclosed little about how their wellness products were validated and how well they work. Oura has promised to publish more information about its blood pressure features in early June, and Russell, the product VP, said the company conducted “extensive validation” using direct arterial measurements as ground truth. A Samsung spokesperson shared that the company used an ISO standard for cuffed devices but did not offer data about the performance of its blood pressure product. |
A new noisy world
There’s a broad feeling among industry observers that the FDA’s wellness guidance update would not have happened if Whoop hadn’t pushed the boundaries. Now patients, clinicians, and developers are left to navigate a new landscape.
Brooke, the regulatory attorney, said it’s unfortunate that FDA created policies geared toward companies that want to avoid regulation, because there are many willing to do the hard work “to do things the right way,” he said.
Cohen, who helped write the AHA scientific statement, said that even before blood pressure wearables were common, she found herself at loggerheads with a patient who insisted a watch purchased online showed normal blood pressure and that elevated readings in the office must be “white coat” hypertension that only shows up in medical settings. A 24-hour reading from an ambulatory blood pressure monitor showed alarming levels of hypertension.
“My big concern is it’s going to create a bigger gap of physician distrust,” she said.
Josep Solà, the co-founder and chief technology officer of Aktiia, said even in the wake of the updated FDA guidance, he believes it’s important for the company to remain focused on clinical applications of its cuffless technology. Still, he would not rule out a wellness offering. He said that the new products from well-known brands like Apple and Samsung help build credibility for his company.
“The negative is that they’re adding a lot of noise to the market,” Solà said, “and more people will also come to the market with wellness things that just make nothing.”