Reanalysis of the 12-Minute Walk in Patients With Chronic Obstructive Pulmonary Disease

doi:10.1378/chest.105.1.163

Chest

Volume 105, Issue 1, January 1994, Pages 163-167

https://doi.org/10.1378/chest.105.1.163 Get rights and content

The purpose of this study was to determine the correlation between different intervals in the 12-min walk test, to determine which of the intervals best correlated with maximal oxygen intake ( $\dot{V}$ o₂max) and maximal CO₂ expelled ( $\dot{V}$ co₂max) and to determine the degree of correlation between changes in the $\dot{V}$ o₂max and changes in the walk test and spirometry. Nine elderly (age, 67 ± 4 years) patients with moderate COPD (FEV₁, 1.32 ± 0.28 L) who were ventilatory limited were seen 6 times over a 14-week period. At each visit they performed spirometry, a 12-min walk, and a symptom-limited maximal exercise test. During the 12-min walk the distances traversed in each 2-min interval were recorded. A Borg score was obtained at the end of each 2 min. The distances that the patients walked in each 2-min interval were very similar, but the mean Borg score became higher the longer the patient walked. The Borg score after 2 min was 1.64 ± 1.15, while the Borg score after 12 min was 5.70 ± 3.59. The correlation coefficients between the distance walked at various intervals and the oxygen consumption ( $\dot{V}$ o₂)/kg (˜ 0.65) and the Vco₂/kg (˜ 0.52) were very similar. However, changes in the Vo₂/kg were more closely correlated with changes in the 12-min walk (r = 0.72), than with changes in the 6-min walk (r = 0.64), the 4-min walk (r = 0.59), or the 2-min walk (r = 0.53). This latter observation suggests that the 12-min walk may be preferable to tests in which the patient walks 4 or 6 min for documenting changes in the exercise capabilities.

Section snippets

Clinical Data

The subjects in the study were recruited from the Outpatient Pulmonary Clinic at the Veterans Administration Medical Center, Long Beach, Cal, to participate in a study to evaluate the effects of buspirone on anxiety and exercise in COPD patients,³ which has been previously reported. The patients agreed to take part in the study and signed informed consent forms approved by the Institutional Review Board at this institution. Since the results of that study showed no significant changes while

Results

The demographics of our patients are shown in Table 1. Nine male patients with a mean age of 67 years took part in the study. The average patient had moderate COPD, as evidenced by the FEV₁ of 1.32 ± 0.28 L. The mean maximal workload achieved in the exercise test was 81 W, which can be compared with the predicted workload of 180 W for men over 60 years of age.⁶ The $\dot{V}$ o₂ max was slightly over a liter. The 12-min walking distance was reduced to a mean of 2,650 ft. Three of our patients

Discussion

Our results show that the distances walked in each 2-min interval of the 12-min walk are very consistent (Fig 1), in contrast to the Borg scores which tend to get progressively higher (Fig 2) as the patient walks for a longer period of time. Significantly, the changes which occur in the results of the maximal exercise test between testing sessions correlate better with changes in the 12-min walking distance test than with changes in shorter walking distance tests.

Cooper¹ used a 12-min running

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There are more references available in the full text version of this article.

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The FTSST is usually applied to reveal the functional lower extremity motor strength.24,25 The 6MWT is associated with the global and integrated responses of the cardiopulmonary and muscular systems.26,27 The changes of these tests after 4 weeks were greater than that regarded as minimal detectable change (10MWT>0.10m/s,33 TUGT>4s,34 FTSST>3.01s,24 6MWT>20m35).
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A randomized controlled trial (single-blinded design) with 6-month prospective fall data follow-up.
Tertiary rehabilitation centers and several communities.
Independent ambulatory individuals (N=54) with SCI who walked with or without a walking device.
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Participants who walked with an average speed of 0.52 m/s and postinjury time >7 years could safely walk over a WTDS. They demonstrated significant improvement at 2 and 4 weeks after experimental training (P<.001), but not after control training. During the 6-month follow-up, participants in the experimental group also had the number of those who fell (n=5, 18%) fewer than those in the control group (n=12, 46%).
Being at a chronic SCI with ability of independent walking, participants needed a challenging task to promote their functional outcomes and minimize fall risk. The findings suggest the use of various surfaces as an alternative rehabilitation strategy for these individuals.
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The 6-minute walk test distance (6MWD) has been shown to be a valid and responsive outcome measure in patients with idiopathic pulmonary fibrosis (IPF). The analyses were based, however, on a single phase 3 trial and require validation in an independent cohort.
To confirm the performance characteristics and estimates of minimal clinically important difference (MCID) of 6MWD in an independent cohort of patients with IPF.
Patients randomized to placebo in the phase 3 CAPACITY trials who had a baseline 6MWD measurement were included in these analyses. The 6MWD and other functional parameters (lung function, dyspnea, and health-related quality of life) were measured at baseline and 24-week intervals. Validity and responsiveness were examined using Spearman correlation coefficients. The MCID was estimated using distribution- and anchor-based methods.
The analysis comprised 338 patients. Baseline 6MWD was significantly correlated with lung function measures, patient-reported outcomes, and quality-of-life measures (validity). Compared with baseline 6MWD, change in 6MWD (responsiveness) showed stronger correlations with change in lung function parameters and quality-of-life measures. Dyspnea measured by the University of California San Diego Shortness of Breath Questionnaire showed the strongest correlations with 6MWD (baseline: coefficient −0.35; 48-week change: coefficient −0.37; both p < 0.001). The distribution-based analyses of MCID using standard error of measurement yielded an MCID of 37 m, and distribution-based analyses by effect size resulted in 29.2 m. The MCID by anchor-based analysis using criterion referencing (health events of hospitalization or death) was 21.7 m.
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El objetivo principal es revisar las herramientas disponibles para valorar la movilidad del paciente amputado de miembro inferior con el fin de identificar las más útiles en cuanto a información clínica, sencillez técnica y tiempo de realización para poder aplicarlas en la práctica clínica diaria. Los individuos que sufren una amputación de miembro inferior presentan un deterioro funcional que afecta a múltiples facetas de la vida, como la movilidad. La movilidad es una necesidad básica física, vital y social y su recuperación óptima es uno de los principales objetivos de los programas de rehabilitación del paciente amputado.
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: Presented in part at 57th Annual Scientific Assembly, American College of Chest Physicians, San Francisco, November 4–8, 1991.

: Supported in part by the Research Service of the Department of Veterans Affairs, and Bristol-Myers, U.S. Pharmaceutical Group.

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Chest

Clinical Investigations: ExerciseReanalysis of the 12-Minute Walk in Patients With Chronic Obstructive Pulmonary Disease

Section snippets

Clinical Data

Results

Discussion

Chest

Clin Chest Med

A means of assessing maximal oxygen intake

JAMA

Twelve-minute walking test for assessing disability in chronic bronchitis

BMJ

Performance, ventilation, and oxygen consumption in three different types of exercise tests in patients with chronic obstructive lung disease

Thorax

Psychophysical basis of perceived exertion

Med Sci Sports Exer

Clinical Investigations: Exercise
Reanalysis of the 12-Minute Walk in Patients With Chronic Obstructive Pulmonary Disease