{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,3,25]],"date-time":"2026-03-25T21:14:41Z","timestamp":1774473281869,"version":"3.50.1"},"reference-count":33,"publisher":"MDPI AG","issue":"23","license":[{"start":{"date-parts":[[2022,12,2]],"date-time":"2022-12-02T00:00:00Z","timestamp":1669939200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Smartphone-based pedometer sensor telemedicine applications could be useful for measuring disease activity and predicting the risk of developing comorbidities, such as pulmonary or cardiovascular disease, in patients with rheumatoid arthritis (RA), but the sensors have not been validated in this patient population. The aim of this study was to validate step counting with an activity-tracking application running the inbuilt Android smartphone pedometer virtual sensor in patients with RA. Two Android-based smartphones were tested in a treadmill test-bed setup at six walking speeds and compared to manual step counting as the gold standard. Guided by a facilitator, the participants walked 100 steps at each test speed, from 2.5 km\/h to 5 km\/h, wearing both devices simultaneously in a stomach pouch. A computer automatically recorded both the manually observed and the sensor step count. The overall difference in device step counts versus the observed was 5.9% mean absolute percentage error. Highest mean error was at the 2.5 km\/h speed tests, where the mean error of the two devices was 18.5%. Both speed and cadence were negatively correlated to the absolute percentage error, which indicates that the greater the speed and cadence, the lower the resulting step counting error rate. There was no correlation between clinical parameters and absolute percentage error. In conclusion, the activity-tracking application using the inbuilt Android smartphone pedometer virtual sensor is valid for step counting in patients with RA. However, walking at very low speed and cadence may represent a challenge.<\/jats:p>","DOI":"10.3390\/s22239396","type":"journal-article","created":{"date-parts":[[2022,12,2]],"date-time":"2022-12-02T03:28:04Z","timestamp":1669951684000},"page":"9396","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Smartphone Pedometer Sensor Application for Evaluating Disease Activity and Predicting Comorbidities in Patients with Rheumatoid Arthritis: A Validation Study"],"prefix":"10.3390","volume":"22","author":[{"given":"Stefan R.","family":"Wagner","sequence":"first","affiliation":[{"name":"Department of Electrical and Computer Engineering, Aarhus University, 8200 Aarhus, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Rasmus R.","family":"Gregersen","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Aarhus University, 8200 Aarhus, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Line","family":"Henriksen","sequence":"additional","affiliation":[{"name":"Department of Electrical and Computer Engineering, Aarhus University, 8200 Aarhus, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Ellen-Margrethe","family":"Hauge","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, Aarhus University Hospital, 8200 Aarhus, Denmark"},{"name":"Department of Clinical Medicine, Aarhus University, 8000 Aarhus, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2474-3389","authenticated-orcid":false,"given":"Kresten K.","family":"Keller","sequence":"additional","affiliation":[{"name":"Department of Rheumatology, Aarhus University Hospital, 8200 Aarhus, Denmark"},{"name":"Department of Clinical Medicine, Aarhus University, 8000 Aarhus, Denmark"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2022,12,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"44","DOI":"10.1002\/art.1780380107","article-title":"Modified disease activity scores that include twenty-eight-joint counts. Development and validation in a prospective longitudinal study of patients with rheumatoid arthritis","volume":"38","author":"Prevoo","year":"1995","journal-title":"Arthritis Rheum."},{"key":"ref_2","first-page":"167","article-title":"The Stanford Health Assessment Questionnaire: A review of its history, issues, progress, and documentation","volume":"30","author":"Bruce","year":"2003","journal-title":"J. Rheumatol."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1186\/s13075-015-0584-7","article-title":"Subjective and objective levels of physical activity and their association with cardiorespiratory fitness in rheumatoid arthritis patients","volume":"17","author":"Yu","year":"2015","journal-title":"Arthritis Res. Ther."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"e000434","DOI":"10.1136\/rmdopen-2017-000434","article-title":"Flares assessed weekly in patients with rheumatoid arthritis or axial spondyloarthritis and relationship with physical activity measured using a connected activity tracker: A 3-month study","volume":"3","author":"Jacquemin","year":"2017","journal-title":"RMD Open"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1690","DOI":"10.1002\/art.24092","article-title":"Risk of cardiovascular mortality in patients with rheumatoid arthritis: A meta-analysis of observational studies","volume":"59","author":"Choi","year":"2008","journal-title":"Arthritis Rheum."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"350","DOI":"10.1093\/rheumatology\/kel253","article-title":"Increased in the early course of disease, in ischaemic heart disease and in pulmonary fibrosis","volume":"46","author":"Young","year":"2007","journal-title":"Rheumatology"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1016\/j.berh.2019.03.013","article-title":"Physical activity, exercise and rheumatoid arthritis: Effectiveness, mechanisms and implementation","volume":"32","author":"Metsios","year":"2018","journal-title":"Best Pract. Res. Clin. Rheumatol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1818","DOI":"10.1111\/sms.13074","article-title":"Validity of activity trackers, smartphones, and phone applications to measure steps in various walking conditions","volume":"28","author":"Knaier","year":"2018","journal-title":"Scand. J. Med. Sci. Sports"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"1509","DOI":"10.1007\/s00296-020-04608-2","article-title":"Measurement of sedentary time and physical activity in rheumatoid arthritis: An ActiGraph and activPAL\u2122 validation study","volume":"40","author":"Duda","year":"2020","journal-title":"Rheumatol. Int."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1080\/02640414.2016.1154592","article-title":"Accuracy of three Android-based pedometer applications in laboratory and free-living settings","volume":"35","author":"Leong","year":"2016","journal-title":"J. Sports Sci."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"3869","DOI":"10.1007\/s00296-011-2283-2","article-title":"Objective assessment of abnormal gait in patients with rheumatoid arthritis using a smartphone","volume":"32","author":"Yamada","year":"2012","journal-title":"Rheumatol. Int."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"737","DOI":"10.2147\/CLEP.S99490","article-title":"The Danish nationwide clinical register for patients with rheumatoid arthritis: DANBIO","volume":"8","author":"Ibfelt","year":"2016","journal-title":"Clin. Epidemiol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"387","DOI":"10.12968\/ijtr.2012.19.7.387","article-title":"Pedometer accuracy in slow-walking older adults","volume":"19","author":"Martin","year":"2012","journal-title":"Int. J. Ther. Rehabil."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"788","DOI":"10.1080\/02640414.2018.1527199","article-title":"Validity of the \u201cSamsung Health\u201d application to measure steps: A study with two different samsung smartphones","volume":"37","author":"Elvira","year":"2019","journal-title":"J. Sports Sci."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"441","DOI":"10.1089\/tmj.2015.0120","article-title":"An Evaluation of Commercial Pedometers for Monitoring Slow Walking Speed Populations","volume":"22","author":"Beevi","year":"2016","journal-title":"Telemed. e-Health"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1089\/tmj.2017.0264","article-title":"Validity and Reliability Evaluation of Four Commercial Activity Trackers\u2019 Step Counting Performance","volume":"24","author":"Petersen","year":"2018","journal-title":"Telemed. e-Health"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"782","DOI":"10.1089\/tmj.2017.0263","article-title":"Validation of Electronic Activity Monitor Devices During Treadmill Walking","volume":"24","author":"Tam","year":"2018","journal-title":"Telemed. e-Health"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e10527","DOI":"10.2196\/10527","article-title":"Accuracy of Fitbit Devices: Systematic Review and Narrative Syntheses of Quantitative Data","volume":"6","author":"Feehan","year":"2018","journal-title":"JMIR mHealth uHealth"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"103153","DOI":"10.1016\/j.jbi.2019.103153","article-title":"Wearable activity trackers, accuracy, adoption, acceptance and health impact: A systematic literature review","volume":"93","author":"Shin","year":"2019","journal-title":"J. Biomed. Inform."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1019","DOI":"10.1089\/tmj.2016.0008","article-title":"The Importance of Walking for Control of Blood Pressure: Proof Using a Telemedicine System","volume":"22","author":"Okura","year":"2016","journal-title":"Telemed. e-Health"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1231","DOI":"10.1089\/tmj.2018.0233","article-title":"Smartphone Application Versus Pedometer to Promote Physical Activity in Prostate Cancer Patients","volume":"25","author":"Lee","year":"2019","journal-title":"Telemed. e-Health"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/acr.23230","article-title":"Physical Activity to Reduce Fatigue in Rheumatoid Arthritis: A Randomized Controlled Trial","volume":"70","author":"Katz","year":"2018","journal-title":"Arthritis Care Res."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"417","DOI":"10.1111\/1756-185X.13460","article-title":"Associations between Health Assessment Questionnaire Disability Index and physical performance in rheumatoid arthritis and osteoarthritis","volume":"22","author":"McCulloch","year":"2019","journal-title":"Int. J. Rheum. Dis."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1336","DOI":"10.1002\/acr.23768","article-title":"Detection of Flares by Decrease in Physical Activity, Collected Using Wearable Activity Trackers in Rheumatoid Arthritis or Axial Spondyloarthritis: An Application of Machine Learning Analyses in Rheumatology","volume":"71","author":"Gossec","year":"2019","journal-title":"Arthritis Care Res."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1093","DOI":"10.2522\/ptj.20150281","article-title":"Criterion Validity of the activPAL Activity Monitor for Sedentary and Physical Activity Patterns in People Who Have Rheumatoid Arthritis","volume":"96","author":"Larkin","year":"2016","journal-title":"Phys. Ther."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"473","DOI":"10.1016\/j.clinbiomech.2013.02.009","article-title":"Concurrent validation of activity monitors in patients with rheumatoid arthritis","volume":"28","author":"Backhouse","year":"2013","journal-title":"Clin. Biomech."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.gaitpost.2019.02.009","article-title":"Activity trackers are not valid for step count registration when walking with crutches","volume":"70","year":"2019","journal-title":"Gait Posture"},{"key":"ref_28","doi-asserted-by":"crossref","unstructured":"Stlind, E., Sant\u2019Anna, A., Eek, F., Stigmar, K., and Ekvall Hansson, E. (2021). Physical activity patterns, adherence to using a wearable activity tracker during a 12-week period and correlation between self-reported function and physical activity in working age individuals with hip and\/or knee osteoarthritis. BMC Musculoskelet. Disord., 22.","DOI":"10.1186\/s12891-021-04338-x"},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"46","DOI":"10.1177\/0894318419881792","article-title":"Orem\u2019s self-care model with multiple sclerosis patients\u2019 balance and motor function","volume":"33","author":"Afrasiabifar","year":"2020","journal-title":"Nurs. Sci. Q."},{"key":"ref_30","first-page":"905","article-title":"Motion sensor accuracy under controlled and free-living conditions","volume":"36","author":"Lee","year":"2004","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Song, Z., Park, H.-J., Thapa, N., Yang, J.-G., Harada, K., Lee, S., Shimada, H., Park, H., and Park, B.-K. (2022). Carrying Position-Independent Ensemble Machine Learning Step-Counting Algorithm for Smartphones. Sensors, 22.","DOI":"10.3390\/s22103736"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"506","DOI":"10.1539\/joh.17-0101-OA","article-title":"Reliability of smartphone-based gait measurements for quantification of physical activity\/inactivity levels","volume":"59","author":"Ebara","year":"2017","journal-title":"J. Occup. Health"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"655","DOI":"10.1089\/tmj.2015.0159","article-title":"A Study to Determine the Most Popular Lifestyle Smartphone Applications and Willingness of the Public to Share Their Personal Data for Health Research","volume":"22","author":"Chen","year":"2016","journal-title":"Telemed. e-Health"}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/23\/9396\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T01:32:30Z","timestamp":1760146350000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/22\/23\/9396"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,12,2]]},"references-count":33,"journal-issue":{"issue":"23","published-online":{"date-parts":[[2022,12]]}},"alternative-id":["s22239396"],"URL":"https:\/\/doi.org\/10.3390\/s22239396","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,12,2]]}}}