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. 2025 Feb 10:13:e55298.
doi: 10.2196/55298.

Validity, Accuracy, and Safety Assessment of an Aerobic Interval Training Using an App-Based Prehabilitation Program (PROTEGO MAXIMA Trial) Before Major Surgery: Prospective, Interventional Pilot Study

Sara Fatima Faqar Uz Zaman  1 , Svenja Sliwinski  1 , Lisa Mohr-Wetzel  2 , Julia Dreilich  2 , Natalie Filmann  3 , Charlotte Detemble  1   4 , Dora Zmuc  1 , Felix Chun  5 , Wojciech Derwich  1   6 , Waldemar Schreiner  1 , Wolf Bechstein  1 , Johannes Fleckenstein  2 , Andreas A Schnitzbauer  1   4
Affiliations

Validity, Accuracy, and Safety Assessment of an Aerobic Interval Training Using an App-Based Prehabilitation Program (PROTEGO MAXIMA Trial) Before Major Surgery: Prospective, Interventional Pilot Study

Sara Fatima Faqar Uz Zaman et al. JMIR Mhealth Uhealth. .

Abstract

Background: Major surgery is associated with significant morbidity and a reduced quality of life, particularly among older adults and individuals with frailty and impaired functional capacity. Multimodal prehabilitation can enhance functional recovery after surgery and reduce postoperative complications. Digital prehabilitation has the potential to be a resource-sparing and patient-empowering tool that improves patients' preoperative status; however, little remains known regarding their safety and accuracy as medical devices.

Objective: This study aims to test the accuracy and validity of a new software in comparison to the gold-standard electrocardiogram (ECG)-based heart rate measurement.

Methods: The PROTEGO MAXIMA trial was a prospective interventional pilot trial assessing the validity, accuracy, and safety of an app-based exercise program. The Prehab App calculates a personalized, risk-stratified aerobic interval training plan based on individual risk factors and utilizes wearables to monitor heart rate. Healthy students and patients undergoing major surgery were enrolled. A structured risk assessment was conducted, followed by a 6-minute walking test and a 37-minute supervised interval session. During the exercise, patients wore app-linked wearables for heart rate and distance measurements, which were compared with standard ECG and treadmill measurements. Safety, accuracy, and usability assessments included testing alarm signals, while the occurrence of adverse events served as the primary and secondary outcome measures.

Results: A total of 75 participants were included. The mean heart rate differences between wearables and standard ECG were ≤5 bpm (beats per minute) with a mean absolute percentage error of ≤5%. Regression analysis revealed a significant impact of the BMI (odds ratio 0.90, 95% CI 0.82-0.98, P=.02) and Timed Up and Go Test score (odds ratio 0.12, 95% CI 0.03-0.55, P=.006) on the accuracy of heart rate measurement; 29 (39%) patients experienced adverse events: pain (5/12, 42%), ECG electrode-related skin irritations (2/42, 17%), dizziness (2/42, 17%), shortness of breath (2/42, 17%), and fatigue (1/42, 8%). No cardiovascular or serious adverse events were reported, and no serious device deficiency was detected. There were no indications of clinically meaningful overexertion based on laboratory values measured before and after the 6-minute walking test and exercise. The differences in means and ranges were as follows: lactate (mmol/l), mean 0.04 (range -3 to 6; P=.47); creatinine kinase (U/l), mean 12 (range -7 to 43; P<.001); and sodium (mmol/l), mean -2 (range -11 to 12; P<.001).

Conclusions: The interventional trial demonstrated the high safety of the exercise program and the accuracy of heart rate measurements using commercial wearables in patients before major surgery, paving the way for potential remote implementation in the future.

Trial registration: German Clinical Trials Register DRKS00026985; https://drks.de/search/en/trial/DRKS00026985 and European Database on Medical Devices (EUDAMED) CIV-21-07-0307311.

International registered report identifier (irrid): RR2-10.1136/bmjopen-2022-069394.

Keywords: accuracy; aerobic; aerobic training; app; digital health; heart rate; major surgery; management; medical device; oncology; pilot study; prehab; prehabilitation; quality of life; safety and quality; safety management; smartwatches; surgery; surgical; surgical oncology; validity; wearable; wearables.

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Conflict of interest statement

Conflicts of Interest: AAS, DZ, and CD are founders of Capreolos GmbH, a spin-off from Goethe University established to set up the regulatory framework for developing a medical device for prehabilitation. JF became a shareholder of Capreolos after the termination of the trial. All other authors declare that they have no direct or indirect conflicts of interest.

Figures

Figure 1
Figure 1
Trial profile for the interventional part of the PROTEGO MAXIMA trial: between March 25, 2022, and September 20, 2022, a total of 77 patients were enrolled, of whom 2 were excluded during exercise training. Finally, 75 patients were included in the statistical analysis.
Figure 2
Figure 2
Bland-Altman plots for wearable measurement versus standard measurement: Bland-Altman plots for wearable heart rate measurements compared with electrocardiogram (ECG) measurements for 4 device combinations. The ECG heart rate, used as the reference, is shown on the x-axis, and the specified differences between ECG and the device are shown on the y-axis. The bold line corresponds to the mean difference, and the dashed lines indicate the 95% limits of agreement.
Figure 3
Figure 3
Bland-Altman plots for wearable measurement versus standard measurement: Bland-Altman plots for wearable distance measurements compared with treadmill measurements for 4 device combinations are depicted.
See this image and copyright information in PMC

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