Background: While various objective tools have been validated for assessing physical frailty in the geriatric population, these are often unsuitable for busy clinics and mobility-impaired patients. Recently, we have developed a frailty meter (FM) using two wearable sensors, which allows capturing key frailty phenotypes (weakness, slowness, and exhaustion), by testing 20-s rapid elbow flexion-extension test. Objective: In this study, we proposed an enhanced automated algorithm to identify frailty using a single wrist-worn sensor. Methods: The data collected from 100 geriatric inpatients (age: 78.9 ± 9.1 years, 49% frail) were reanalyzed to validate the new algorithm. The frailty status of the participants was determined using a validated modified frailty index. Different FM phenotypes (31 features) including velocity of elbow rotation, decline in velocity of elbow rotation over 20 s, range of motion, etc. were extracted. A regression model, bootstrap with 2,000 iterations, and recursive feature elimination technique were used for optimizing the FM parameters and identifying frailty using a single wrist-worn sensor. Results: A strong agreement was observed between two-sensor and wrist-worn sensor configuration (r = 0.87, p < 0.001). Results suggest that the wrist-worn FM with no demographic information still yields a high accuracy of 80.0% (95% CI: 79.7-80.3%) and an area under the curve of 87.7% (95% CI: 87.4-87.9%) to identify frailty status. Results are comparable with two-sensor configuration, where the observed accuracy and area under the curve were 80.6% (95% CI: 80.4-80.9%) and 87.4% (95% CI: 87.1-87.6%), respectively. Conclusion: The simplicity of FM may open new avenues to integrate wearable technology and mobile health to capture frailty status in a busy hospital setting. Furthermore, the reduction of needed sensors to a single wrist-worn sensor allows deployment of the proposed algorithm in the form of a smartwatch application. From the application standpoint, the proposed FM is superior to traditional physical frailty-screening tools in which the walking test is a key frailty phenotype, and thus they cannot be used for bedbound patients or in busy clinics where administration of gait test as a part of routine assessment is impractical.

Keywords:
Frailty phenotype, Wearable technology, Geriatric population, Frailty meter, Mobile health
1.
Etzioni DA, Liu JH, O'Connell JB, Maggard MA, Ko CY: Elderly patients in surgical workloads: a population-based analysis. Am Surg 2003;69:961-965.
2.
Vincent GK, Velkoff VA: The Next Four Decades: The Older Population in the United States: 2010 to 2050. Washington, US Department of Commerce, Economics and Statistics Administration, US Census Bureau, 2010.
3.
Chow WB, Rosenthal RA, Merkow RP, Ko CY, Esnaola NF, et al: Optimal preoperative assessment of the geriatric surgical patient: a best practices guideline from the American College of Surgeons National Surgical Quality Improvement Program and the American Geriatrics Society. J Am Coll Surg 2012;215:453-466.
4.
Makary MA, Segev DL, Pronovost PJ, Syin D, Bandeen-Roche K, Patel P, Takenaga R, Devgan L, Holzmueller CG, Tian J: Frailty as a predictor of surgical outcomes in older patients. J Am Coll Surg 2010;210:901-908.
5.
Robinson TN, Wu DS, Pointer L, Dunn CL, Cleveland JC Jr, Moss M: Simple frailty score predicts postoperative complications across surgical specialties. Am J Surg 2013;206:544-550.
6.
Lasithiotakis K, Petrakis J, Venianaki M, Georgiades G, Koutsomanolis D, Andreou A, Zoras O, Chalkiadakis G: Frailty predicts outcome of elective laparoscopic cholecystectomy in geriatric patients. Surg Endosc 2013;27:1144-1150.
7.
Fried LP, Tangen CM, Walston J, Newman AB, Hirsch C, Gottdiener J, Seeman T, Tracy R, Kop WJ, Burke G, McBurnie MA; Cardiovascular Health Study Collaborative Research Group: Frailty in older adults: evidence for a phenotype. J Gerontol A Biol Sci Med Sci 2001;56:M146-M156.
8.
Schwenk M, Howe C, Saleh A, Mohler J, Grewal G, Armstrong D, Najafi B: Frailty and technology: a systematic review of gait analysis in those with frailty. Gerontology 2014;60:79-89.
9.
Rockwood K, Song X, MacKnight C, Bergman H, Hogan DB, McDowell I, Mitnitski A: A global clinical measure of fitness and frailty in elderly people. CMAJ 2005;173:489-495.
10.
Searle SD, Mitnitski A, Gahbauer EA, Gill TM, Rockwood K: A standard procedure for creating a frailty index. BMC Geriatr 2008;8:24.
11.
Cesari M, Gambassi G, van Kan GA, Vellas B: The frailty phenotype and the frailty index: different instruments for different purposes. Age Ageing 2014;43:10-12.
12.
Clegg A, Young J, Iliffe S, Rikkert MO, Rockwood K: Frailty in elderly people. Lancet 2013;381:752-762.
13.
Yang F, Gu D: Predictability of frailty index and its components on mortality in older adults in China. BMC Geriatr 2016;16:145.
14.
Rockwood K, Mitnitski A: Frailty defined by deficit accumulation and geriatric medicine defined by frailty. Clin Geriatr Med 2011;27:17-26.
15.
Robinson TN, Walston JD, Brummel NE, Deiner S, Brown CH 4th, Kennedy M, Hurria A: Frailty for surgeons: review of a national institute on aging conference on frailty for specialists. J Am Coll Surg 2015;221:1083-1092.
16.
Rockwood K, Andrew M, Mitnitski A: A comparison of two approaches to measuring frailty in elderly people. J Gerontol A Biol Sci Med Sci 2007;62:738-743.
17.
Carriere I, Colvez A, Favier F, Jeandel C, Blain H, et al: Hierarchical components of physical frailty predicted incidence of dependency in a cohort of elderly women. J Clin Epidemiol 2005;58:1180-1187.
18.
Ravaglia G, Forti P, Lucicesare A, Pisacane N, Rietti E, Patterson C: Development of an easy prognostic score for frailty outcomes in the aged. Age Ageing 2008;37:161-166.
19.
Studenski S, Hayes RP, Leibowitz RQ, Bode R, Lavery L, Walston J, Duncan P, Perera S: Clinical global impression of change in physical frailty: development of a measure based on clinical judgment. J Am Geriatr Soc 2004;52:1560-1566.
20.
Mohler J, Najafi B, Fain M, Ramos KS: Precision medicine: a wider definition. J Am Geriatr Soc 2015;63:1971-1972.
21.
Wile DJ, Ranawaya R, Kiss ZH: Smart watch accelerometry for analysis and diagnosis of tremor. J Neurosci Methods 2014;230:1-4.
22.
Deutsch M, Burgsteiner H: A smartwatch-based assistance system for the elderly performing fall detection, unusual inactivity recognition and medication reminding. Stud Health Technol Inform 2016;223:259-266.
23.
Casilari E, Oviedo-Jimenez MA: Automatic fall detection system based on the combined use of a smartphone and a smartwatch. PLoS One 2015;10:e0140929.
24.
Mortazavi B, Nemati E, VanderWall K, Flores-Rodriguez HG, Cai JY, Lucier J, Naeim A, Sarrafzadeh M: Can smartwatches replace smartphones for posture tracking? Sensors (Basel) 2015;15:26783-26800.
25.
Toosizadeh N, Mohler J, Najafi B: Assessing upper extremity motion: an innovative method to identify frailty. J Am Geriatr Soc 2015;63:1181-1186.
26.
Toosizadeh N, Joseph B, Heusser MR, Orouji Jokar T, Mohler J, Phelan HA, Najafi B: Assessing upper-extremity motion: an innovative, objective method to identify frailty in older bed-bound trauma patients. J Am Coll Surg 2016;223:240-248.
27.
Toosizadeh N, Najafi B, Reiman EM, Mager RM, Veldhuizen JK, O'Connor K, Zamrini E, Mohler J: Upper-extremity dual-task function: an innovative method to assess cognitive impairment in older adults. Front Aging Neurosci 2016;8:167.
28.
Joseph B, Toosizadeh N, Orouji Jokar T, Heusser MR, Mohler J, Najafi B: Upper-extremity function predicts adverse health outcomes among older adults hospitalized for ground-level falls. Gerontology 2017;63:299-307.
29.
Joseph B, Pandit V, Zangbar B, Kulvatunyou N, Tang A, O'Keeffe T, Green DJ, Vercruysse G, Fain MJ, Friese RS, Rhee P: Validating trauma-specific frailty index for geriatric trauma patients: a prospective analysis. J Am Coll Surg 2014;219:10-17 e11.
30.
Guyon I, Weston J, Barnhill S, Vapnik V: Gene selection for cancer classification using support vector machines. Mach Learn 2002;46:389-422.
31.
Zhu W: Making bootstrap statistical inferences: a tutorial. Res Q Exerc Sport 1997;68:44-55.
32.
Efron B, Tibshirani RJ: An Introduction to the Bootstrap. Boca Raton, CRC Press, 1994.
33.
Najafi B, Lee-Eng J, Wrobel JS, Goebel R: Estimation of center of mass trajectory using wearable sensors during golf swing. J Sports Sci Med 2015;14:354-363.
34.
Lin HS, Watts JN, Peel NM, Hubbard RE: Frailty and post-operative outcomes in older surgical patients: a systematic review. BMC Geriatr 2016;16:157.
35.
Van Epps P, Oswald D, Higgins PA, Hornick TR, Aung H, Banks RE, Wilson BM, Burant C, Graventstein S, Canaday DH: Frailty has a stronger association with inflammation than age in older veterans. Immun Ageing 2016;13:27.
36.
Partridge JS, Harari D, Dhesi JK: Frailty in the older surgical patient: a review. Age Ageing 2012;41:142-147.
37.
Coley B, Jolles BM, Farron A, Bourgeois A, Nussbaumer F, Pichonnaz C, Aminian K: Outcome evaluation in shoulder surgery using 3d kinematics sensors. Gait Posture 2007;25:523-532.
© 2017 S. Karger AG, Basel
2017
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.