We examined the feasibility of home-based walking training to maintain the benefits of a short-term exercise training in patients with severe chronic obstructive pulmonary disease (COPD). After initial recovery from an exacerbation, 46 patients were randomized into a training and a control group, and 30 patients completed the programme (mean +/- SD FEV1, 36 +/- 7% predicted). The training group performed a 10-day walking training programme in the hospital, followed by a 6-month programme of supervised walking training at home, integrated into daily activities. The control group did not have exercise training in the hospital or at home. Until 6 months after discharge, lung function, exercise performance and symptom scores were assessed. Six-minute walking distance in the training group improved from day 1 to day 10 (P<0.001) and this effect was maintained over 6 months (P<0.001). On average, daily walking distance at home was 2308 m and walking was reported on 157 days. Quality of life (QoL) scores changed significantly over 6 months (P<0.001). The control group showed no significant changes in exercise performance or QoL scores throughout the whole study period. Therefore, (i) significant improvements in exercise performance and Chronic Respiratory Disease Questionnaire (CRQ) scores could be achieved after recovery from an exacerbation and (ii) these improvements were maintained after discharge, when supported by a home-based walking training.

Background: Pulmonary rehabilitation is successful in improving exercise capacity and quality of life in patients with chronic obstructive pulmonary disease (COPD). However, training effects diminish over time. Objectives:We evaluated the effects of simple, daily, structured, self-monitored, home-based exercise training for patients with moderate COPD after a 3-week outpatient rehabilitation. Methods: We conducted a randomized, controlled, observer-blind trial. Twenty patients were recruited. Ten patients performed home-based exercise training (mean age 67 years, 95% confidence interval [CI] 63–72; FEV₁ 58.6%, 95% CI 53.8–63.4), and 10 patients served as controls (mean age 72 years, 95% CI 69–77; FEV₁ 62.5%, 95% CI 57.7–67.3). At baseline, and after 3 and 6 months, we assessed exercise capacity (6-min walk test, 6MWT, primary endpoint), health-related quality of life (Chronic Respiratory Questionnaire, CRQ) and lung function. An intention-to-treat analysis was performed using two-way ANOVA models for comparison of time trends between random groups. Results: The training group had better results than the control group in 6MWT (p = 0.033), in CRQ total (p = 0.027), CRQ dyspnea (p = 0.014) and CRQ fatigue (p = 0.016). Improvement in FEV₁ was also better in the intervention group than in the control group (p = 0.007). Conclusions: We demonstrated that training effects obtained from an outpatient rehabilitation program can be maintained by home-based exercise training in patients with moderate COPD.

Background: Assessment of health-related quality of life (HRQL) is important in patients with chronic obstructive pulmonary disease (COPD). Despite the high prevalence of COPD in Germany, Switzerland and Austria there is no validated disease-specific instrument available. The objective of this study was to translate the Chronic Respiratory Questionnaire (CRQ), one of the most widely used respiratory HRQL questionnaires, into German, develop an interviewer-and selfadministered version including both standardised and individualised dyspnoea questions, and validate these versions in two randomised studies.

Hydrogen peroxide (H 2 O 2 ) is known to be detectable in exhaled air. The present study aimed to determine whether the concentration of exhaled H 2 O 2 depends on expiratory flow rate in order to make inferences on the site of its production within the lung.Breath condensate was collected in cooled Teflon tubes, at three different expiratory flow rates, in 15 healthy or mild asthmatic subjects. Tests were repeated 2±5 times to assess reproducibility.Mean SEM concentrations of H 2 O 2 at flow rates of 140, 69 and 48 mL . s -1 were 0.12 0.02, 0.19 0.02 and 0.32 0.03 mM, respectively. These values differed significantly from each other (p<0.001). For comparison, average coefficients of variability within repeated measurements at each of the three flow rates were 68, 62 and 82%, respectively.These data demonstrate that the concentration of exhaled hydrogen peroxide depends on expiratory flow rate. Since flow dependence is an indicator of production within the airways, this result suggests that, to a large extent, the exhaled hydrogen peroxide originates within the airways. However, even under strictly controlled conditions, a high degree of variability persists, which may limit the usefulness of exhaled hydrogen peroxide as a marker of airway inflammation.

The chronic respiratory questionnaire (CRQ) has demonstrated excellent measurement properties in patients with chronic obstructive pulmonary disease (COPD), but in its original form it is limited by the requirement for interviewer-administration and the individualised dyspnoea questions. The objective of this randomised trial was to examine the evaluative properties of the interviewer and self-administered German CRQ as well as of a standardised CRQ dyspnoea domain. In a multinational trial we randomly allocated 71 patients with COPD to complete the interviewer administered CRQ (CRQ-IA) or the self-administered CRQ (CRQ-SA) and other validation measures at the beginning and end of a respiratory rehabilitation program. We assessed and compared responsiveness and longitudinal validity of the CRQ. The change scores of all CRQ domains were above the minimal clinically important difference of 0.5. Responsiveness of the fatigue domain was higher for the CRQ-SA compared to CRQ-IA (P = 0.02), but there was no difference in responsiveness on the other domains. Compared to the standardised dyspnoea domain the individualised dyspnoea questions tended to show greater responsiveness for both the CRQ-IA (P = 0.07) and CRQ-SA (P = 0.10). We found better longitudinal validity for the CRQ-SA represented by larger correlations between CRQ change scores and those of other validation instruments. Taken these results into consideration, researchers in COPD, in particular those in German-language countries can utilise any one of four CRQ formats that have proved both valid and responsive.