[Chronic obstructive pulmonary disease: evaluation of exercise tolerance using three different exercise tests]

Relationship of phase angle and peak torque of knee extensors with the performance in six-minute step test in haemodialysis patients

BACKGROUND

Chronic kidney disease is a systemic disease affecting not only renal function, but also endocrine, cardiovascular, and skeletal muscle systems, with broad impact on functionality. Therefore, the assessment of body composition, peripheral muscle function, and exercise tolerance is also of great importance in this population. In addition, the development of reliable strategies that use feasible tools in clinical practice is of great importance in the functional diagnosis, clinical management and prescription of physical activity.

OBJECTIVE

To assess the relationship between phase angle and peak torque of knee extensors with the performance in six-minute step test of patients with chronic kidney disease undergoing haemodialysis.

METHODS

Observational and cross-sectional study at Haemodialysis Centre of Sírio-Libanês Hospital. The evaluations took place 3 days before the haemodialysis sessions. On the first day, patients underwent anthropometric evaluation and biochemical tests (lactate, urea, creatinine, albumin, ferritin and growth factor similar to insulin type 1 [IGF1]). On the second day, performed electrical bioimpedance and exercise tolerance assessed using the six-minute step test. On the last day, the evaluation of knee extensor muscles strength using isokinetic dynamometry was performed.

RESULTS

Eighteen subjects were included, with a mean age of 62.3 ± 17.6 years. A positive linear correlation was observed between the phase angle, derived from the electrical bioimpedance, and the performance in six-minute step test in these patients. It was also possible to observe a linear correlation between phase angle and IGF1, handgrip strength, peak torque of knee extensors and quality of life questionnaire. The peak torque of knee extensors also presented a linear correlation with IGF1, the performance in six-minute step test and mal-nutrition and inflammation score.

CONCLUSION

Phase angle and peak torque of knee extensors were correlated with the performance in six-minute step test. Therefore, the phase angle seems to be an important marker of reduced peripheral muscle function and exercise tolerance in haemodialysis patients.

Stair-Climbing Capacity as a Marker of Improvement Following Pulmonary Rehabilitation

PURPOSE

The aim of this study was to explore the potential and safety of a stair-climbing test as a tool to monitor improvement following pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD).

METHODS

Stair-climbing capacity was assessed in 139 patients with COPD before and after a comprehensive 8-week PR program, which included stair-climbing training. Stair-climbing capacity was assessed as the total number of flights of stairs climbed without stopping. A constant work rate endurance test (CET) was also performed before and after PR. Change in stair-climbing after PR (Δstairs) was compared and correlated to the change in endurance time (ΔCET) and, for 40 patients, to the change in COPD assessment test (ΔCAT) score.

RESULTS

Most patients had moderate to severe COPD (mean forced expiratory volume in 1 second = 54% ± 20% predicted). Stair-climbing capacity, endurance time, and CAT score improved after PR (2.8 ± 1.4 vs 8.3 ± 3.3 flights, 408 ± 272 vs 717 ± 415 seconds, and 20.0 ± 6.4 vs 17.6 ± 6.6 units, respectively; P value for all < .001). Δstairs was moderately correlated to ΔCET (r = 0.49; P < .001) and well correlated to ΔCAT (r = -0.71; P < .001). Patients with greater change in Δstairs had better baseline resting lung function and aerobic capacity. No adverse events were reported during stair-climbing.

CONCLUSION

Stair-climbing is responsive to training in patients with COPD and is correlated to the change in CAT score following PR. Although the test requires further standardization, it could eventually be used as a simple and safe way to assess improvement following interventions in COPD.

Recommendations for fitness for work medical evaluations in chronic respiratory patients. Spanish Society of Pulmonology and Thoracic Surgery (SEPAR)

Chronic respiratory diseases often cause impairment in the functions and/or structure of the respiratory system, and impose limitations on different activities in the lives of persons who suffer them. In younger patients with an active working life, these limitations can cause problems in carrying out their normal work. Article 41 of the Spanish Constitution states that «the public authorities shall maintain a public Social Security system for all citizens guaranteeing adequate social assistance and benefits in situations of hardship». Within this framework is the assessment of fitness for work, as a dual-nature process (medico-legal) that aims to determine whether it is appropriate or not to recognise a person's right to receive benefits which replace the income that they no longer receive as they cannot carry out their work, due to loss of health. The role of the pulmonologist is essential in evaluating the diagnosis, treatment, prognosis and functional capacity of respiratory patients. These recommendations seek to bring the complex setting of fitness for work evaluation to pulmonologists and thoracic surgeons, providing action guidelines that allow them to advise their own patients about their incorporation into working life.

Role of exercise in testing and in therapy of COPD

The stair-climbing test, 6MWT, and shuttle test are exercise tests that requires less technical support than the CPET and are more available to any physician. The 6MWT is the simplest and most likely to be cost effective, as it provides useful information regarding prognosis, ADLs, and health care use at a very low cost. In addition, the 6MWT can be used to evaluate response to several interventions, including physical rehabilitation, medications, lung volume reduction interventions, and transplantation. The 6MWT has also been useful in and has become an integral part of the evaluation and response to treatment in other medical conditions, including congestive heart failure, pulmonary hypertension, and pulmonary fibrosis. The stair-climbing test seems to be most useful for preoperative evaluations when a CPET is not available. We have also used it on patients unable to perform a good CPET because of lack of familiarity with bicycle pedaling. The shuttle walk test may be used to better determine a maximal exercise capacity when a CPET is not available and to measure the effects of pulmonary rehabilitation in patients unfamiliar with a CPET. The role of exercise as a therapeutic tool is central to the concept of pulmonary rehabilitation. Exercise training improves not only functional dyspnea and health-related quality of life, but also has been shown to decrease health care resource use. As part of a comprehensive pulmonary rehabilitation initiated after a hospitalization for exacerbation, it has been shown to decrease readmission rates.

Replacement of the 6-min Walk Test With Maximal Oxygen Consumption in the BODE Index Applied to Patients With COPD

INTRODUCTION

Patients with COPD have decreased exercise capacity and low oxygen consumption (Vo(2)) during formal cardiopulmonary exercise testing, and lower scores on health-related quality of life questionnaires. When isolated, these three variables show different correlations with COPD mortality. The multidimensional BODE (body mass index[BMI], airflow obstruction, dyspnea, and exercise capacity in COPD) index, which comprises four variables including the 6-min walk test (6MWT), predicts survival in COPD.

OBJECTIVES

To evaluate the degree of association between the values of the BODE index using the 6MWT with the BODE index using maximal Vo(2) (Vo(2)max) obtained in a maximal incremental test.

MATERIALS AND METHODS

Fifty patients with mild-to-severe COPD (average age, 63.5 +/- 9.9 years; FEV(1), 65.3 +/- 23.6% of predicted) [+/- SD] had BMI, spirometric function (FVC and FEV(1)), and dyspnea status (Medical Research Council) evaluated. Two BODE index scores were then completed: one with the 6MWT, and one with the Vo(2)max obtained during maximal incremental testing on a treadmill.

RESULTS

Correlation between BODE index and Vo(2) in milliliters per minute per kilogram (r = - 0.41) was weak; the correlation was moderate (r = - 0.64) when Vo(2) percentage of predicted was used. The BODE index modified by replacing the 6MWT with Vo(2) showed excellent correlations with Vo(2) in milliliters per minute per kilogram (r = 0.92) and Vo(2) percentage of predicted (r = 0.95).

CONCLUSION

The excellent correlation between the conventional BODE index and the modified BODE index with Vo(2) replacing the 6MWT enables us to reach the conclusion that the original BODE index is very effective in the evaluation of COPD patients.