False positives with Apple Watch could tie up health resources


Apple’s latest ad campaign for its Apple Watch makes much of its ability to monitor health functions – but researchers are concerned it may encourage people to seek medical attention prematurely.

A study of people who consulted a doctor after an abnormal pulse was detected by their device suggests it could lead to false positives that mean unnecessary healthcare visits, according to the team from the Mayo Clinic.

The study – published in the Journal of the American Medical Informatics Association (JAMIA) – found that it would take seven consultations based on the Watch’s pulse monitoring function to yield one case that warranted medical follow-up.

The authors say the FDA should consider the unintended consequences of widespread screening for ‘silent’ atrial fibrillation (AFib) using the Apple Watch abnormal pulse detection function “by populations in whom the device has not been adequately studied.”

The FDA has approved the latest versions of Apple’s device – which include a pulse monitor and single-lead electrocardiogram (ECG) – for use of these features, but has said it is concerned about false positive results leading to additional unnecessary medical procedures.

The approval emphasises that the device should not be used to replace traditional methods of diagnosis or treatment.

The regulator also specified that the ECG and irregular rhythm notification functions are not intended to be used by people under the age of 22, a group which made up around 9% of the 264-subject sample, or those previously diagnosed with AFib.

Pre-existing AFib was found in 58 (22%) of the sample, but an “actionable cardiovascular diagnosis of interest” was established in only 30 – or just over 11%. That included six out of 21 patients (15%) who had received a specific alert from the Apple Watch, according to the researchers. Most patients were symptomatic at the time an abnormal pulse was detected.

“False positive screening results have the potential to lead to excessive healthcare resource utilisation and anxiety among the ‘worried well’,” write the study authors.

“Stricter access controls are encouraged to ensure real-world use conforms with FDA guidance,” they add.

Earlier this year, Apple and partner Johnson & Johnson started enrolling patients in a study that will investigate whether the Apple Watches could be used to detect early signs of AFib.

J&J and Apple want to see if the Apple Watch can be used alongside an app developed by the pharma company to “accelerate the diagnosis and improve health outcomes of the 33 million people worldwide” living with the disease.

Apple now has a couple of competitors in the market for its ECG-enabled Watch, including the FitBit Sense, Samsung Galaxy Watch, Nokia unit Withings’ Move ECG sensor and ScanWatch, and AliveCor’s KardiaMobile devices.