Introduction

Wearable devices are ubiquitous. Over 30%–45% of U.S. adults use wearable devices, and their use is predicted to grow by 24.7% annually to create a U.S. market of $139.35 billion by 2026.¹ The popularity of wearable devices has translated to their use in health care. Wearables allow clinicians to remotely monitor patients, resulting in reduced physician visits and improved health outcomes.² Insurance companies now offer wearable devices to promote healthy lifestyles, and have even offered incentives on the basis of targets. These devices have particular promise in the perioperative setting, where physical activity, sleep, and health trends can be monitored at a time when complications and readmissions remain at their highest. Additionally, wearable devices have shown potential in the field of urology, with 82% of patients reporting they would incorporate these devices into their urological treatment.³ Herein, we outline some of the current uses of wearable devices in urology.

Prostate Cancer

Wearable devices have been used successfully in prostate cancer patients. A study examining men on active surveillance showed that the Fitbit is able to track step counts.⁴ Furthermore, patients are accepting of the technology. The Fitbit was worn 98% of the time and 90.6% of patients were satisfied with the Fitbit. Wearable devices have also been used to provide insights into recovery after prostatectomy. In 2018, the team at Mayo Clinic Rochester utilized a Fitbit to track step counts and sleep in patients undergoing radical prostatectomy.⁵ The device was well received by patients and the authors found a significant decrease in steps taken postoperatively, but no difference in minutes slept or nighttime awakenings.

Bladder Cancer

In a prospective single-center study, authors at Cedars-Sinai examined if wearable monitors could predict length of stay after major surgery.⁶ Patients, including those undergoing robotic cystectomy, wore a Fitbit on postoperative day (POD) 0 until discharge. The authors found that step count on POD1 was linearly associated with a decreased probability of prolonged length of stay up to 1,000 steps. Wearable monitors were shown to be an inexpensive platform to determine daily step counts. The authors proposed that wearables should be considered a “sixth vital sign” for health care teams.

In another prospective single-center study, a wearable monitor was used to track the physical activity and sleep habits of patients in the radical cystectomy perioperative period.⁷ The authors found that radical cystectomy patients had no differences in sleep throughout the perioperative period. However, there was a 50% decrease in moderate intensity exercise at POD30. These authors argue that wearable monitors can track objective measures of recovery after radical cystectomy and should be implemented into future cystectomy studies.

Men’s Health

Men’s sexual health represents an emerging field for wearable devices. The HuMOVE (Human Movement) device is an electronic patch worn on a man’s back that tracks movement during sexual intercourse. The device allows physicians to evaluate for premature or delayed ejaculation through analysis of movement during intercourse. Although the device was validated to accurately measure intravaginal ejaculation latency and sexual performance,⁸ the device is not yet commercially available.

A variety of other male sexual health wearables have been introduced, although literature on their efficacy is lacking. FirmTech is a penile ring recently introduced at the 2022 Sexual Medicine Society of North America meeting. It is an electronic penile ring that syncs with a patient’s smartphone to measure the number, duration, and firmness of one’s erection. It can also be used to monitor nocturnal penile tumescence. Data can be uploaded to share with clinicians. The MOR device is a wearable electrode placed on the perineum to delay premature ejaculation. The device syncs to one’s smartphone so that neuromodulation can be adjusted during intercourse to delay ejaculation. Data from the efficacy study, DELAID, has not been published, although the manufacturer is aiming for commercial release in 2023.

Urinary Incontinence

Multiple companies have developed wearable ultrasonic bladder monitors to reduce rates of urinary incontinence. The SENS-U is an ultrasound device designed for the pediatric population and worn on the lower abdomen. It continuously estimates bladder volume and notifies the user when their bladder is full via vibrations or phone notification. The device also serves as an automatic voiding diary that can be shared with clinicians. It has been validated against urodynamic testing as an accurate tool for determining bladder volume. DFree is another wearable bladder ultrasound that works similarly to SENS-U but is designed for adults.

Nephrolithiasis

Maintaining adequate hydration is a cornerstone of kidney stone prevention. As a result, multiple studies have investigated the use of a smart water bottle to increase fluid intake. The HidrateSpark is a water bottle that syncs to one’s smartphone to record fluid intake and reminds patients to stay hydrated. Initial studies show that the HidrateSpark is successful in increasing 24-hour urine volumes (1.37 L vs 0.79 L).⁹ A large multicenter trial is currently underway, which aims to enroll 1,642 participants to determine if the HidrateSpark leads to changes in symptomatic stone episodes and urine output.¹⁰

Fashion Trends

Adoption of any new technology follows a well-established “S curve,” in which various barriers to adoption must be overcome. Similarly, wearables in urology must address multiple issues until their widespread utilization. Patients often do not wear or charge their devices. The accuracy and reliability of wearables might not be proven until additional large-scale trials are performed. Cost considerations and reimbursement pose additional hurdles. The tracking of personal information also presents a multitude of privacy concerns. Finally, urologists must be careful to ensure that wearables do not devolve into what electronic health records have become: a seemingly unending array of data points contributing to physician burnout. Before large-scale integration of wearables, ask yourself, how will you manage an increasing number of inbox messages filled with blood pressure measurements, step counts, and post-void residuals? What is the clinical utility of this data, and will physicians be liable for these results? Until all these challenges are met, we are likely to see wearable technology in urology come and go.