Brock O'Neil, MD

Across the U.S., wearable devices are worn by roughly 10% to 20% of the population, with projected increases in use each year. Most devices offer tracking of parameters such as steps, heart rate, sleep, and calories burned. Though there is great potential for their use in health monitoring, little is known about the role wearables play in current care delivery models, and even less is known about their use in perioperative optimization and monitoring.

In this article, we discuss the current use of wearable devices in health care and review recent studies examining the role of wearables in the urologic surgery setting.

Google has recently joined forces with Stanford University and Duke University on Project Baseline, a study seeking to enroll 10,000 participants to wear a proprietary wearable device that measures heart rate, steps, movement, and electrodermal activity. With this, researchers aim to establish baseline health characteristics across a wide spectrum of the population (ages 18 to 80 years) as well as understand how different activities and health events affect the wearable data 

Studies such as these will be transformative in understanding how to implement wearables in health care.

Use of wearables in surgical patients, particularly those undergoing major surgery, poses some unique challenges. Current trackers are adept at recognizing and recording step and movement data; however, after undergoing major procedures, individuals don’t move as purposefully as prior to surgery, with gait patterns often becoming more shuffled. Current trackers aren’t tuned to recognizing these subtler movements and likely understate postoperative activity. This has led to the development of more surgery-specific activity trackers, though their testing remains unreported and none are commercially available.

Heart rate monitoring has become a standard feature on nearly all wearables on the market today. This is clinically useful as heart rate acts as a surrogate for a number of common postoperative complications such as dehydration or infection. For this reason, many of the wearables designed for patient monitoring focus their capabilities on heart rate monitoring, such as VitalPatch by VitalConnect (figure), which is an adhesive wearable patch worn over the heart. It is designed to identify cardiac arrhythmias in addition to respiratory rate, skin temperature, steps, and fall detection.

The potential that heart rate monitors have for early detection of illness was made manifest by a Stanford study of 43 individuals who wore activity trackers for 11 months. The study showed they were capable of detecting heart rate aberrancies 48-72 hours prior to reported episodes of illness and was the first to suggest wearables may be capable of early detection of illness 

Wearable devices have the potential to change the landscape of preoperative optimization as well as postoperative monitoring of high-risk patients or patients undergoing high-risk surgeries. For example, cystectomy has 90-day readmission rates as high as 40%. The ability to identify patients at risk for or in the early stages of serious postoperative complications, such as sepsis, would not only improve outcomes but also save millions in health care dollars. As an added bonus, reliable at-home monitoring would also potentially allow for early discharge and increased willingness of patients to discharge early.

A 2017 survey examining urology patient perspectives on wearing physical activity monitors was sent to all patients treated at Mayo Clinic in Rochester, MN during a 6-month period. The survey had 1,043 responders (19%), 20% of whom reported already using a wearable activity monitor and 82% of whom would be willing to use one for their medical care 

2017; 4:508-14). Though this study is limited by its single-institution nature, limited survey response, and response bias, these findings suggest a high level of patient acceptance for involving wearable technology into care.

Several studies using wearables in the urologic surgery setting are either underway or recently completed (table).

In 2016, Mayo Clinic Rochester performed a feasibility study on 42 patients undergoing radical prostatectomy. The participants were provided with a Fitbit Charge HR for 3-4 days preoperatively and wore the device for 1 week. While the wearables were well received by patients, only 69% had retrievable data. Of those who had retrievable data, overall device compliance varied from 75% to 95% 

2016; 30[S2], abs. MP6-14). The study highlights the challenges surrounding the use of wearables currently on the market, which require heavy user dependency for charging and wearing the device as well as maintaining a Bluetooth phone connection for data syncing.

A team at the University of Kansas utilized activity monitors as part of a preoperative optimization plan for overweight patients prior to prostatectomy. Though wearing the activity monitor was only one part of a series of interventions that included behavior coaching, diet, and physical activity, the 15 patients in the intervention arm experienced an average 6 kg of weight loss, 11 mg/dL reduction in fasting glucose, 8 mm Hg reduction in systolic blood pressure, and a reduction in the leptin to adiponectin ratio. Weight loss was maintained at 12 weeks post-prostatectomy, and physical quality of life was noted to be better in the intervention group 

A 2018 abstract from the United Kingdom tested the feasibility of wearing fitness trackers on patients undergoing radical cystectomy for bladder cancer. A component of this study was to correlate number of steps, as a surrogate for patient activity, with the 30-second sit-to-stand test and EQ-5DL-5L standardized health and mobility questionnaire. Of the 30 patients initially included in the study, 26 complied with wearing the device. The 7-day median daily post-cystectomy step count was 5,498 and did not correlate with the sit-to-stand test or EQ-5DL-5L 

While this study is still in an early phase, it demonstrates the feasibility of activity monitoring in cystectomy patients as well as the uniqueness of activity data. Given the lack of correlation with validated mobility measures, the question remains whether this device is adequately sensitive to capture postoperative movement or is measuring a unique movement domain altogether.

A similar study from the University of Southern California used wearables to track patient steps, daily calories burned, and sleep characteristics before hospitalization, during hospitalization, and after cystectomy. The authors found patients on average recorded 4,806 daily steps preoperatively, and in contrast with the UK study, only averaged 1,517 steps per day postoperatively. Average sleep was found to be 5.3 hours per day preoperatively and 4.9 hours postoperatively 

2018; 199:e336, abs. MP26-04). The introduction of sleep monitoring adds another variable to potential remote postoperative monitoring via wearable devices, although its clinical implications remain unknown.

The University of Kansas is conducting an ongoing National Institutes of Health-sponsored study evaluating feasibility of a carbohydrate-restricted diet and exercise regimen in diabetic patients with bladder cancer. Adherence to the exercise regimen will be monitored by wearable activity trackers 

2018; 199: e234, abs. PD11-03). This study will add to the growing knowledge of preoperative optimization as a mean of improving postoperative outcomes.

The University of Utah is wrapping up a pilot study investigating the use of wearables with the Garmin VivofitHR to monitor cystectomy patients for 30 days postoperatively. The goal is to evaluate heart rate, steps, and sleep to identify if there are alterations associated with postoperative complications.

While millions of individuals worldwide wear activity monitors around, little is known about how this information can be used to improve preoperative optimization, enhance remote monitoring postoperatively, and improve surgical outcomes. Fortunately, with the large-scale studies such as Google’s Project Baseline and the many others within urology, progress is being made toward utilizing the great potential that wearable devices hold in health care and in urology.

 is assistant professor in the division of urology, department of surgery, at the University of Utah School of Medicine, Salt Lake City.

 is assistant professor of surgery (urology) at the Center for Reconstructive Urology and Men's Health, University of Utah, Salt Lake City, and 

 is professor of urology, Icahn School of Medicine at Mount Sinai, New York.

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