Thomas E. Dolmage

Interval versus continuous training in individuals with chronic obstructive pulmonary disease--a systematic review.

Background In patients with chronic obstructive pulmonary disease (COPD), interval exercise has gained recent attention as a possible means of achieving greater physiological training effects compared with continuous exercise. The primary aim of this systematic review was to compare the effects of interval versus continuous training on peak oxygen uptake, peak power, 6 minute walk test (6MWT) distance and health-related quality of life in individuals with COPD. Methods Randomised controlled trials comparing the effects of interval versus continuous training in patients with COPD were identified after searches of six databases and reference lists of appropriate studies in May 2009. Two reviewers independently assessed study quality. Weighted mean differences (WMD) with 95% CIs were calculated using a random effects model for measures of exercise capacity and health-related quality of life. Results: Eight randomised controlled trials, with a total of 388 patients with COPD, met the inclusion criteria. No significant differences were found for peak power (WMD 1 W, 95% CI −1 to 3) or peak oxygen uptake (WMD −0.04 l/min, 95% CI −0.13 to 0.05) between interval and continuous training. The WMD for the Chronic Respiratory Questionnaire dyspnoea score was −0.2 units (95% CI −0.5 to 0.0). There was no difference in 6MWT distance between groups (WMD 4 m, 95% CI −15 to 23). Conclusions Interval and continuous training modalities did not differ in their effect on measures of exercise capacity or health-related quality of life. Interval training may be considered as an alternative to continuous training in patients with varying degrees of COPD severity.

Measurement properties of the SenseWear armband in adults with chronic obstructive pulmonary disease

Rationale The SenseWear armband (SAB) is designed to measure energy expenditure (EE). In people with chronic obstructive pulmonary disease (COPD), EE estimated using the SAB (EESAB) is a popular outcome measure. However, a detailed analysis of the measurement properties of the SAB in COPD is lacking. Objective To examine the sensitivity of EESAB, agreement between EESAB and EE measured via indirect calorimetry (EEIC), and its repeatability in COPD. Methods 26 people with COPD (forced expiratory volume in 1 s (FEV1)=49±18% predicted; 15 males) spent 6 min in five standardised tasks that comprised supine, sitting, standing and two walking speeds. A subgroup (n=12) walked using a rollator. Throughout each task, measurements of EESAB and EEIC were collected. The protocol was repeated on a second day. Results EESAB increased between standing and slow walking (2.4, metabolic equivalents (METs) 95% CI 2.2 to 2.7) as well as slow and fast walking (0.5 METs, 95% CI 0.3 to 0.7). Considering all tasks together, the difference between EESAB and EEIC was −0.2 METs (p=0.21) with a limit of agreement of 1.3 METs. The difference between days in EESAB was 0.0 METs with a coefficient of repeatability of 0.4 METs. Rollator use increased the variability in EESAB, compromising its repeatability and agreement with EEIC. Conclusions EESAB was sensitive to small but important changes. There was fair agreement between EESAB and EEIC, and measurements of EESAB were repeatable. These observations suggest that the SAB is useful for the evaluation of EE in patients with COPD who walk without a rollator.

Chronic Obstructive Pulmonary Disease and SocioEconomic Status: a Systematic Review

Abstract Background. Along with age and sex, socioeconomic status is one of the most powerful determinants of health. We conducted a systematic review to examine the consistency and magnitude of the association between socioeconomic status and COPD health outcomes to determine the potential impact of SES disparity on the COPD population. Methods. Electronic databases to October 2011 were searched for studies of adults who had or were at risk for COPD that quantified an association between a measure of socioeconomic status and at least one COPD health outcome. Two authors independently reviewed studies, assessed study quality, and for eligible studies, extracted data. Results. Regardless of the population, socioeconomic status measure or COPD outcome examined, with few exceptions, consistent significant inverse associations between socioeconomic status and COPD outcomes were found. Most studies found that individuals of the lowest socioeconomic strata were at least twice as likely to have poor outcomes as those of the highest (range from no difference to 10-fold difference). Conclusions. Social and economic disadvantage appears to have a significant consistent impact on COPD mortality and morbidity. These findings point to the need for public health strategies and research to address socioeconomic status disparity in individuals with COPD.

Comparing peak and submaximal cardiorespiratory responses during field walking tests with incremental cycle ergometry in COPD

Background and objective:  Field and laboratory‐based tests are used to measure exercise capacity in people with COPD. A comparison of the cardiorespiratory responses to field tests, referenced to a laboratory test, is needed to appreciate the relative physiological demands. We sought to compare peak and submaximal cardiorespiratory responses to the 6‐min walk test, incremental shuttle walk test and endurance shuttle walk test with a ramp cycle ergometer test (CET) in patients with COPD.

Resistance arm training in patients with COPD: A Randomized Controlled Trial.

BACKGROUND The study aimed to evaluate the effect of upper extremity resistance training for patients with COPD on dyspnea during activity of daily living (ADL), arm function, arm exercise capacity, muscle strength, and health-related quality of life (HRQL). METHODS Patients were randomly assigned to an intervention or control group. The intervention group underwent arm resistance training. The control group performed a sham. Both groups exercised three times a week for 6 weeks. Dyspnea during ADL and HRQL were measured using the Chronic Respiratory Disease Questionnaire (CRDQ). Arm function and exercise capacity were measured using the 6-min pegboard and ring test (6PBRT) and the unsupported upper limb exercise test (UULEX), respectively. Muscle strength for the biceps, triceps, and anterior and middle deltoids was obtained using an isometric dynamometer. RESULTS Thirty-six patients with COPD (66 ± 9 years) participated in the study. Compared with the control group, the magnitude of change in the intervention group was greater for the 6PBRT (P = .03), UULEX (P = .01), elbow flexion force (P = .01), elbow extension force (P = .02), shoulder flexion force (P = .029), and shoulder abduction force (P = .01). There was no between-group difference in dyspnea during ADL, HRQL, or symptoms during the 6PBRT or UULEX (all P values > .08). CONCLUSIONS Resistance-based arm training improved arm function, arm exercise capacity, and muscle strength in patients with COPD. No improvement in dyspnea during ADL, HRQL, or symptoms was demonstrated.

Measurement of peripheral muscle strength in individuals with chronic obstructive pulmonary disease: a systematic review.

PURPOSE: Reduced maximal, peripheral muscle strength is associated with exercise intolerance in patients with chronic obstructive pulmonary disease (COPD). Therefore, it is important to accurately evaluate muscle strength to identify patients with muscle weakness and to prescribe adequate loads for resistance training. The objective here was to systematically identify and summarize the literature on measurement of peripheral muscle strength in individuals with COPD and to make recommendations for strength testing in clinical and research settings. METHODS: A literature search was conducted of electronic databases between 1999 and 2009 of all English language articles utilizing muscle strength measurements. RESULTS: The search resulted in retrieval of 178 articles, of which 66 were reviewed. Isometric muscle strength was measured using handgrip (n = 30), strain gauge (n = 15), computerized dynamometer (n = 13), magnetic stimulation (n = 8), handheld dynamometer (n = 6), or manual testing (n = 3). Isotonic muscle strength was measured using a hydraulic system (n = 3) or 1-repetition maximum (n = 9), and isokinetic muscle strength was measured using computerized dynamometer (n = 16). Methodological issues such as limb position, number of trials, subject familiarization, test instructions, rest periods, and muscle group tested were all identified as important variables to consider when developing a strength-testing protocol. CONCLUSION: Muscle strength has been measured in people with COPD using similar methods as in other clinical populations. Each method presents advantages and disadvantages that need to be considered when selecting the most relevant measure. Standardization of the test procedures is essential in both clinical and research settings to obtain valid and reliable measurements of muscle strength.

Has My Patient Responded?: Interpreting Clinical Measurements such as the Six Minute Walk Test

To correctly interpret clinical measurements it is necessary to understand the standard deviation and the standard error; the former reflects the range or variability of individuals within a sample and the latter reflects the precision for which the group parameters have been estimated. When evaluating an individual patient, test measurement properties such as repeatability will assist in concluding whether a repeated test, measured to monitor the response to an intervention, has changed beyond its natural variability. Using the “best” test has an inherent bias and ignores the natural test variation, whereas the average of repeated tests is more representative of the true value, making it more discriminative to change. Serial measurements to follow progress will increase a clinicians confidence in the observed effects of treatment.

Modifying Track Layout From Straight to Circular Has a Modest Effect on the 6-min Walk Distance

BACKGROUND The protocol used for the 6-min walk test (6MWT) influences its results. The only study to examine the effect of modifying track layout performed a retrospective analysis and concluded that institutions using continuous tracks yield greater distances than those using straight tracks. Agreement between the distances measured on different tracks could not be examined. We evaluated the effect of modifying track layout on walk distance and examined the agreement and repeatability of distances measured on different tracks. METHODS In a prospective, randomized, cross-over study, 27 COPD subjects (FEV(1), 38 +/- 14% [mean +/- SD]; 15 men) attended three separate test sessions, completing six 6MWTs. To familiarize all subjects with both tracks, the first two sessions comprised two 6MWTs on either a circular or straight track. During the final session, each subject was tested once on the straight and once on the circular track. RESULTS The distance walked on the circular track exceeded the straight track by 13 +/- 17 m (p < 0.001). The limit of agreement between tracks was 33 m. Coefficient of repeatability values when the test was completed on different days for the straight and circular tracks were 51 m and 65 m, respectively. CONCLUSIONS When evaluating changes in 6-min walk distance in groups of patients, track layout should be standardized. However, the effect of modifying track layout on an individuals walking distance is small compared to their daily variability in walk distance. Therefore, standardizing track layout for any given individual may be inconsequential when evaluating the change in distances from tests performed on different days.

Pulmonary Rehabilitation: A Review of the Recent Literature

Pulmonary rehabilitation (PR) is an evidence-based, multidisciplinary, comprehensive intervention that can be integrated into the management of individuals with chronic lung disease. It aims to reduce symptoms, optimize function, increase participation in daily life, and reduce health-care resource utilization. In this review, we summarize the new developments in PR over the past 5 years. Issues related to patient assessment include a comparison of cycle- and walking-based measures of exercise capacity, the emergence of multidimensional indices, the refinement of the minimal clinically important difference, and the importance of assessing physical activity. Issues related to exercise training focus on strategies to optimize the training load. We also comment on the acquisition of self-management skills, balance training, optimizing access, and maintaining gains following completion of PR.

Is Quadriceps Endurance Reduced in COPD?: A Systematic Review

BACKGROUND Although the aerobic profile of the quadriceps muscle is reduced in COPD, there is conflicting evidence regarding whether this leads to reduced quadriceps muscle endurance. We, therefore, performed a systematic review of studies comparing quadriceps endurance in individuals with COPD with that in healthy control subjects. METHODS Relevant studies were identified by searching six electronic databases (1946-2011). Full-text articles were obtained after two researchers independently reviewed the abstracts. The results were combined in a random effects meta-analysis, and metaregression models were fitted to assess the influence of the type of measurement. RESULTS Data were extracted from 21 studies involving 728 individuals with COPD and 440 healthy control subjects. Quadriceps endurance was reduced in those with COPD compared with healthy control subjects (standardized mean difference, 1.16 [95% CI, 1.02-1.30]; P < .001) with a 44.5 s (4.5-84.5 s; P = .029) reduction in COPD (large effect size) when measured using a nonvolitional technique. The relationship between quadriceps endurance in those with COPD and control subjects did not differ when comparing nonvolitional and volitional techniques (P = .22) or when high- or low-intensity tasks (P = .44) were undertaken. CONCLUSIONS Quadriceps endurance is reduced in individuals with COPD compared with healthy control subjects, independent of the type of task performed.