Sarah Bernard

Histochemical and morphological characteristics of the vastus lateralis muscle in patients with chronic obstructive pulmonary disease.

PURPOSE AND METHODS In this study, we examined the fiber-type proportions, cross-sectional areas (CSA), and capillarization from needle biopsies of the vastus lateralis muscle in 20 patients with chronic obstructive pulmonary disease (COPD) (FEV1 = 37 +/- 11% predicted, peak VO2 = 13 +/- 4 mL.min-1.kg-1) and nine age-matched normal subjects (peak VO2 = 33 +/- 7 mL.min-1.kg-1). The effects of endurance training on these parameters were also evaluated in 11 of the 20 patients with COPD. RESULTS The proportion of Type I fiber was smaller in COPD than normals (34 +/- 14% vs 58 +/- 16 in normals, P < 0.0005) with a corresponding increase in Type IIb fiber (P = 0.015). The CSA of Type I, IIa, and IIab fibers was also smaller in COPD. The capillary to fiber ratio tended to be reduced in patients, but this difference did not reach statistical significance (P = 0.15). The number of capillary contact for Type I, IIa, and IIab fibers was significantly reduced in COPD compared with normal subjects (P < 0.05). When corrected for the CSA, this parameter was similar for both groups. After training, peak VO2 increased by 11% (P < 0.05), the fiber-type proportion remained unchanged, and the CSA of Type I and IIa fibers increased by 31 and 21%, respectively (P < 0.05). Although the number of capillary contact for each fiber types increased with training, the capillary to fiber ratio and the number of capillary contact for the different fiber types relative to their CSA remain unchanged. CONCLUSIONS We conclude that in COPD, 1) the vastus lateralis muscle is characterized by a marked decrease in Type I fiber proportion, an increase in Type IIb fiber proportion, a decrease in Type I, IIa, and IIab fiber CSA and by a relatively preserved capillarization; and 2) a 12-wk training program induces a significant increase in Type I and IIa CSA.

Assessing the impact of pulmonary rehabilitation on functional status in COPD

Background: The optimal way of assessing the impact of pulmonary rehabilitation on functional status in chronic obstructive pulmonary disease (COPD) is currently unknown. The minimal clinically important difference for the constant work rate cycling exercise test also needs to be investigated to facilitate its interpretation. A study was undertaken to evaluate the changes in the 6-min walking test and in the constant work rate cycle endurance test immediately following and 1 year after pulmonary rehabilitation, together with the importance of these changes in terms of health status in patients with COPD. Methods: Patients with COPD of mean (SD) age 65 (8) years and mean (SD) forced expiratory volume in 1 s (FEV1) 45 (15)% predicted were recruited from a multicentre prospective cohort study and evaluated at baseline, immediately after a pulmonary rehabilitation programme (n = 157) and at 1 year (n = 106). The 6-min walking test and the cycle endurance test were performed at each evaluation. Health status was evaluated with the St George Respiratory Questionnaire. Results: Following pulmonary rehabilitation, cycle endurance time increased (198 (352) s, p<0.001) and stayed over baseline values at 1 year (p<0.001). The 6-min walking distance also showed improvements following rehabilitation (25 (52) m, p<0.001) but returned to baseline values at the 1-year follow-up. Changes in cycle endurance time were more closely associated with changes in health status than with the 6-min walking test. An improvement of 100–200 s in the cycle endurance time was associated with clinically meaningful changes in the St George Respiratory Questionnaire scores. Conclusions: The cycle endurance test was more responsive than the 6-min walking test in detecting improvement in exercise tolerance following pulmonary rehabilitation, and was also better correlated with improvements in health status. An improvement in the cycle endurance time of 100–200 s appeared to be clinically meaningful.

The impact of obesity on walking and cycling performance and response to pulmonary rehabilitation in COPD.

BackgroundWe examined the influence of overweight and obesity on pulmonary function, exercise tolerance, quality of life and response to pulmonary rehabilitation in COPD.Methods261 patients with COPD were divided into three groups: normal body mass index (BMI), overweight and obese. Baseline and post rehabilitation pulmonary function, 6-min walking test (6MWT), endurance time during a constant workrate exercise test (CET) and St. Georges Respiratory Questionnaire (SGRQ) scores were compared between all three classes of BMI.ResultsAt baseline, obese and overweight patients had less severe airflow obstruction compared to normal BMI patients. There was no baseline difference in CET performance or SGRQ scores across BMI classes and 6MWT was reduced in the presence of obesity (p < 0.01). Compared to baseline, post-rehabilitation 6MWT, CET performance and SGRQ scores improved significantly in each group (p < 0.01), but 6MWT was still significantly lower in the presence of obesity.ConclusionsWalking, but not cycling performance was worse in obese patients. This difference was maintained post rehabilitation despite significant improvements. Weight excess may counterbalance the effect of a better preserved respiratory function in the performance of daily activities such as walking. However, obesity and overweight did not influence the magnitude of improvement after pulmonary rehabilitation.

Fatigue in COPD: prevalence and effect on outcomes in pulmonary rehabilitation.

Patients with chronic obstructive pulmonary disease (COPD) complain of dyspnea and fatigue. We sought to estimate the prevalence of high fatigue in this population and to determine whether individuals with high fatigue had a different response to pulmonary rehabilitation. This observational study was embedded within a randomized trial. Participants underwent 3 months of pulmonary rehabilitation including education and exercise training. We divided 251 individuals into low and high fatigue groups using population normal scores of the SF-36 vitality domain. Baseline data included spirometry, 6-minute walk distance (6MWD), peak exercise capacity, constant workrate cycling endurance time, and questionnaires including the St. George’s and Chronic Respiratory questionnaires (SGRQ, CRQ). The response to pulmonary rehabilitation was evaluated using changes in these measures at 3 months and 1 year after entry. High fatigue was present in 97/251 (39%) of patients. High fatigue patients were younger, had more depressive symptoms, greater dyspnea and poorer SGRQ scores (p < 0.01). They also had lower 6MWD, endurance times, and peak volume of oxygen consumption (VO2; p < 0.05). Patients in both groups improved similarly in their dyspnea, the 6MWD and endurance time. High-fatigue patients had greater improvements in both the CRQ fatigue (by 0.74 more points) and the SGRQ scores (by 6.0 points; p < 0.01), with clinically significant gains maintained at 1 year. This study suggests that high levels of fatigue is a common feature in patients with COPD. They have a lower exercise capacity and a lower health status. However, they benefit from pulmonary rehabilitation.

A Canadian, multicentre, randomized clinical trial of home-based pulmonary rehabilitation in chronic obstructive pulmonary disease: rationale and methods.

BACKGROUND Pulmonary rehabilitation remains largely underused. Self-monitored, home-based rehabilitation is a promising approach to improving the availability of pulmonary rehabilitation. OBJECTIVE To report the rationale and methods of a trial comparing the effectiveness of self-monitored, home-based rehabilitation with hospital-based, outpatient rehabilitation in patients with chronic obstructive pulmonary disease (COPD). STUDY DESIGN A parallel-group, randomized, noninferiority, multicentre trial will be performed with 240 patients with moderate to severe COPD. INTERVENTION Patients will be randomly assigned to conventional, supervised, hospital-based outpatient rehabilitation or self-monitored, home-based rehabilitation. Both interventions will include a standardized, comprehensive self-management program, in addition to the hospital-based outpatient or home-based exercise program. After the three-month intervention, patients in both groups will be encouraged to continue exercising at home. Patients will be assessed monthly with telephone interviews and in person at enrollment, three months and 12 months. OUTCOMES The dyspnea domain of the Chronic Respiratory Questionnaire (CRQ) at 12 months is the primary outcome variable. Secondary outcome variables include total and domain-specific CRQ scores; exercise tolerance and activity of daily living; health service use over the one-year study period; and direct and indirect costs of COPD treatment. ANALYSIS An intent-to-treat approach will be used as the primary analysis. The primary analysis will focus on the change in the CRQ dyspnea score using a two-sided t distribution based on 95% CIs. The same approach will be used for secondary continuous outcome variables. CONCLUSION The present trial will address two unresolved issues in pulmonary rehabilitation for patients with COPD: the short-term and long-term effectiveness of home-based pulmonary rehabilitation strategies. The authors will also determine if home-based pulmonary rehabilitation can reduce health service use (eg, hospitalizations and emergency visits) and if it can be done at a lower cost than the traditional hospital-based outpatient pulmonary rehabilitation.

Multi-center, randomized, placebo-controlled trial of nocturnal oxygen therapy in chronic obstructive pulmonary disease: a study protocol for the INOX trial

BackgroundLong-term oxygen therapy (LTOT) is the only component of the management of chronic obstructive pulmonary disease (COPD) that improves survival in patients with severe daytime hypoxemia. LTOT is usually provided by a stationary oxygen concentrator and is recommended to be used for at least 15–18 h a day. Several studies have demonstrated a deterioration in arterial blood gas pressures and oxygen saturation during sleep in patients with COPD, even in those not qualifying for LTOT. The suggestion has been made that the natural progression of COPD to its end stages of chronic pulmonary hypertension, severe hypoxemia, right heart failure, and death is dependent upon the severity of desaturation occurring during sleep. The primary objective of the International Nocturnal Oxygen (INOX) trial is to determine, in patients with COPD not qualifying for LTOT but who present significant nocturnal arterial oxygen desaturation, whether nocturnal oxygen provided for a period of 3 years decreases mortality or delay the prescription of LTOT.MethodsThe INOX trial is a 3-year, multi-center, placebo-controlled, randomized trial of nocturnal oxygen therapy added to usual care. Eligible patients are those with a diagnosis of COPD supported by a history of past smoking and obstructive disease who fulfill our definition of significant nocturnal oxygen desaturation (i.e., ≥ 30% of the recording time with transcutaneous arterial oxygen saturation < 90% on either of two consecutive recordings). Patients allocated in the control group receive room air delivered by a concentrator modified to deliver 21% oxygen. The comparison is double blind. The primary outcome is a composite of mortality from all cause or requirement for LTOT. Secondary outcomes include quality of life and utility measures, costs from a societal perspective and compliance with oxygen therapy. The follow-up period is intended to last at least 3 years.DiscussionThe benefits of LTOT have been demonstrated whereas those of nocturnal oxygen therapy alone have not. The INOX trial will likely determine whether supplemental oxygen during sleep is effective in reducing mortality, delaying the need for LTOT and improving health-related quality of life in patients with COPD who desaturate overnight.Trial registrationCurrent Controlled Trials ISRCTN50085100; ClinicalTrials.gov NCT01044628 (date of registration: January 6, 2010).

Combining Both Generic and Disease-Specific Properties: Development of the McGill COPD Quality of Life Questionnaire

Presently, a generic and a disease-specific questionnaire are often co-administered to capture the different domains of quality of life in chronic obstructive pulmonary disease (COPD) subjects. A health-related-quality of life (HRQL) questionnaire in COPD combining both generic and disease-specific properties is needed. Objective: To develop a new, hybrid-HRQL questionnaire, the McGill-COPD-questionnaire, with qualities of both generic and disease-specific instruments. Using pre-defined criteria, we selected items from the SF-36 to complement the items from a COPD-specific-module to create the new hybrid-HRQL-questionnaire. Domains were identified via confirmatory factor analysis. The McGill COPD questionnaire is available in English and French; it assesses three domains: symptoms, physical-function and feelings, has 29 items: 17 from the COPD-specific-module and 12 from the SF-36. The symptom sub-scale has 6 items, all from the COPD-specific-module; the feelings sub-scale has 10 items, 5 each from COPD-specific-module and SF-36 and the physical-function sub-scale has 13 items, 6 from COPD-specific-module and 7 from SF-36. The McGill COPD questionnaire was developed using a novel method of combining items from the SF-36 and a COPD-specific-module. Thus, this new questionnaire has items from a generic-questionnaire and a disease-specific-module and, hence, is promising to be a stand alone quality-of-life questionnaire for COPD subjects.

Lactate Kinetics during Exercise in Chronic Obstructive Pulmonary Disease

OBJECTIVES: To examine whether the lactate kinetics during exercise are abnormal in patients with chronic obstructive pulmonary disease (COPD) and to evaluate the relationship of lactate kinetics with functional status.

Utility Scores In Patients With Oxygen-Dependent COPD: A Case-Control Study.

Abstract Background: Utility measures that summarize the health-related quality of life of an individual using a single number usually between 0 (death) and 1 (full health) are useful to quantify the benefits of health care interventions in terms of quality-adjusted life years (QALYs) and to help prioritizing limited health resources from cost-effectiveness analyses among patients with different health conditions. Objective: To determine utility scores in patients with oxygen-dependent chronic obstructive pulmonary disease (COPD). Methods: Patients with oxygen-dependent COPD (the cases) were matched, on a 1:2 basis, to COPD controls according to gender, age (± 5 years) and FEV1 (±5% predicted). Utility scores were obtained from the SF-6D, a measure derived from the SF-36. Results: From a cohort of 102 patients with oxygen-dependent COPD, 68 (42 men; mean age: 71 years; mean FEV1: 35% predicted) were successfully matched with 136 controls. We found clinically and statistically significant differences in mean utility scores between cases (0.588 ± 0.071) and controls (0.627 ± 0.085; p = 0.001). The same differences were observed in men and women. Conclusion: Oxygen-dependence adds to the burden of disease in terms of quality of life. These utility scores may be useful in cost-utility analyses involving patients with oxygen-dependent COPD.

Prescribing exercise training in pulmonary rehabilitation: a clinical experience.

Built around exercise training, pulmonary rehabilitation (PR) is a multidisciplinary, evidence-based, comprehensive approach to working with the patient as a whole and not just the pulmonary component of the disease. Integrated into the individualized treatment, this intervention aims to reduce symptoms, optimize functional status, increase participation in daily life, and reduce health care costs through stabilizing or reversing systemic manifestations of the disease. Although there are many other components that should be considered to manage the impairment and symptom burden, supervised exercise training is considered the cornerstone of effective pulmonary rehabilitation. This paper addresses our clinical experience at Institut universitaire de cardiologie et de pneumologie de Québec to assess and manage exercise training in line with the current recommendations and guidelines surrounding PR.