Journal article
Normative data of a smartphone app-based 6-minute walking test, test-retest reliability, and content validity with patient-reported outcome measures.
- Tosic L 1Department of Neurosurgery, University Hospital Zurich and Clinical Neuroscience Center, University of Zurich, Switzerland.
- Goldberger E 1Department of Neurosurgery, University Hospital Zurich and Clinical Neuroscience Center, University of Zurich, Switzerland.
- Maldaner N 2Department of Neurosurgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
- Sosnova M 2Department of Neurosurgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
- Zeitlberger AM 2Department of Neurosurgery, Cantonal Hospital St. Gallen, St. Gallen, Switzerland.
- Staartjes VE 1Department of Neurosurgery, University Hospital Zurich and Clinical Neuroscience Center, University of Zurich, Switzerland.
- Gadjradj PS 3Department of Neurosurgery, Leiden University Medical Center, Leiden, The Netherlands.
- Eversdijk HAJ 4Department of Neurosurgery, Bergman Clinics, Amsterdam, The Netherlands.
- Quddusi A 5Center for Neuroscience, Queens University, Kingston, Ontario, Canada.
- Gandía-González ML 6Department of Neurosurgery, Hospital Universitario La Paz, Madrid, Spain.
- Sayadi JJ 7Department of Neurosurgery, Stanford University Hospital and Clinics, Stanford, California; and.
- Desai A 7Department of Neurosurgery, Stanford University Hospital and Clinics, Stanford, California; and.
- Regli L 1Department of Neurosurgery, University Hospital Zurich and Clinical Neuroscience Center, University of Zurich, Switzerland.
- Gautschi OP 8Neuro and Spine Center, Hirslanden Clinic St. Anna, Lucerne, Switzerland.
- Stienen MN 1Department of Neurosurgery, University Hospital Zurich and Clinical Neuroscience Center, University of Zurich, Switzerland.
- 2020-05-30
Published in:
- Journal of neurosurgery. Spine. - 2020
6-minute walking test
6WD = 6-minute walking distance
6WT = 6-minute walking test
ASA = American Society of Anesthesiologists
COMI = Core Outcome Measures Index
COPD = chronic obstructive pulmonary disease
DDD = degenerative disc disease
GPS = Global Positioning System
HRQoL = health-related quality of life
ICC = intraclass correlation coefficient
LDH = lumbar disc herniation
LSS = lumbar spinal stenosis
MRC = Medical Research Council
OFI = objective functional impairment
PROM = patient-reported outcome measure
SEM = standard error of measurement
TUG = Timed Up and Go
VAS = visual analog scale
ZCQ = Zurich Claudication Questionnaire
degenerative disc disease
neurogenic claudication
normative data
objective functional impairment
reliability
spinal stenosis
spine surgery
test qualities
validity
English
OBJECTIVE
The 6-minute walking test (6WT) is used to determine restrictions in a subject's 6-minute walking distance (6WD) due to lumbar degenerative disc disease. To facilitate simple and convenient patient self-measurement, a free and reliable smartphone app using Global Positioning System coordinates was previously designed. The authors aimed to determine normative values for app-based 6WD measurements.
METHODS
The maximum 6WD was determined three times using app-based measurement in a sample of 330 volunteers without previous spine surgery or current spine-related disability, recruited at 8 centers in 5 countries (mean subject age 44.2 years, range 16-91 years; 48.5% male; mean BMI 24.6 kg/m2, range 16.3-40.2 kg/m2; 67.9% working; 14.2% smokers). Subjects provided basic demographic information, including comorbidities and patient-reported outcome measures (PROMs): visual analog scale (VAS) for both low-back and lower-extremity pain, Core Outcome Measures Index (COMI), Zurich Claudication Questionnaire (ZCQ), and subjective walking distance and duration. The authors determined the test-retest reliability across three measurements (intraclass correlation coefficient [ICC], standard error of measurement [SEM], and mean 6WD [95% CI]) stratified for age and sex, and content validity (linear regression coefficients) between 6WD and PROMs.
RESULTS
The ICC for repeated app-based 6WD measurements was 0.89 (95% CI 0.87-0.91, p < 0.001) and the SEM was 34 meters. The overall mean 6WD was 585.9 meters (95% CI 574.7-597.0 meters), with significant differences across age categories (p < 0.001). The 6WD was on average about 32 meters less in females (570.5 vs 602.2 meters, p = 0.005). There were linear correlations between average 6WD and VAS back pain, VAS leg pain, COMI Back and COMI subscores of pain intensity and disability, ZCQ symptom severity, ZCQ physical function, and ZCQ pain and neuroischemic symptoms subscores, as well as with subjective walking distance and duration, indicating that subjects with higher pain, higher disability, and lower subjective walking capacity had significantly lower 6WD (all p < 0.001).
CONCLUSIONS
This study provides normative data for app-based 6WD measurements in a multicenter sample from 8 institutions and 5 countries. These values can now be used as reference to compare 6WT results and quantify objective functional impairment in patients with degenerative diseases of the spine using z-scores. The authors found a good to excellent test-retest reliability of the 6WT app, a low area of uncertainty, and high content validity of the average 6WD with commonly used PROMs.
The 6-minute walking test (6WT) is used to determine restrictions in a subject's 6-minute walking distance (6WD) due to lumbar degenerative disc disease. To facilitate simple and convenient patient self-measurement, a free and reliable smartphone app using Global Positioning System coordinates was previously designed. The authors aimed to determine normative values for app-based 6WD measurements.
METHODS
The maximum 6WD was determined three times using app-based measurement in a sample of 330 volunteers without previous spine surgery or current spine-related disability, recruited at 8 centers in 5 countries (mean subject age 44.2 years, range 16-91 years; 48.5% male; mean BMI 24.6 kg/m2, range 16.3-40.2 kg/m2; 67.9% working; 14.2% smokers). Subjects provided basic demographic information, including comorbidities and patient-reported outcome measures (PROMs): visual analog scale (VAS) for both low-back and lower-extremity pain, Core Outcome Measures Index (COMI), Zurich Claudication Questionnaire (ZCQ), and subjective walking distance and duration. The authors determined the test-retest reliability across three measurements (intraclass correlation coefficient [ICC], standard error of measurement [SEM], and mean 6WD [95% CI]) stratified for age and sex, and content validity (linear regression coefficients) between 6WD and PROMs.
RESULTS
The ICC for repeated app-based 6WD measurements was 0.89 (95% CI 0.87-0.91, p < 0.001) and the SEM was 34 meters. The overall mean 6WD was 585.9 meters (95% CI 574.7-597.0 meters), with significant differences across age categories (p < 0.001). The 6WD was on average about 32 meters less in females (570.5 vs 602.2 meters, p = 0.005). There were linear correlations between average 6WD and VAS back pain, VAS leg pain, COMI Back and COMI subscores of pain intensity and disability, ZCQ symptom severity, ZCQ physical function, and ZCQ pain and neuroischemic symptoms subscores, as well as with subjective walking distance and duration, indicating that subjects with higher pain, higher disability, and lower subjective walking capacity had significantly lower 6WD (all p < 0.001).
CONCLUSIONS
This study provides normative data for app-based 6WD measurements in a multicenter sample from 8 institutions and 5 countries. These values can now be used as reference to compare 6WT results and quantify objective functional impairment in patients with degenerative diseases of the spine using z-scores. The authors found a good to excellent test-retest reliability of the 6WT app, a low area of uncertainty, and high content validity of the average 6WD with commonly used PROMs.
- Language
-
- English
- Open access status
- closed
- Identifiers
-
- DOI 10.3171/2020.3.SPINE2084
- PMID 32470938
- Persistent URL
- https://sonar.ch/global/documents/298729
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