Dyspnea-induced Limitation (DYSLIM), a new self-administered concise questionnaire to evaluate dyspnea-related activity limitation in chronic respiratory diseases.

BACKGROUND AND AIM: Few questionnaires are available for routine assessment of dyspnea. The study aimed to design a self-administered questionnaire assessing the impact of chronic dyspnea on daily activities, named DYSLIM (Dyspnea-induced Limitation). METHODS: The development followed 4 steps: 1: selection of relevant activities and related questions (focus groups); 2: clinical study: internal and concurrent validity vs. modified Medical Research Council (mMRC), Baseline Dyspnea Index (BDI) and Saint George Respiratory Questionnaire (SGRQ); 3: item reduction; 4: responsiveness. Eighteen activities (from eating to climbing stairs) were considered with 5 modalities for each: doing the task slowly, taking breaks, seeking assistance, changing habits, and activity avoidance. Each modality was graded from 5 (never) to 1 (very often). Validation study included 194 patients: COPD (FEV1 ≥ 50% pred: n = 40; FEV1 < 50% pred: n = 65); cystic fibrosis (n = 30), interstitial lung disease (n = 30), pulmonary hypertension (n = 29). Responsiveness was evaluated by post-pulmonary rehabilitation data in 52 COPD patients. RESULTS: Acceptability was high and short term (7 days) reproducibility was satisfactory (Kappa mostly above 0.7). Concurrent validity was high vs. mMRC (Spearman correlation coefficient, r = 0.71), BDI (r = - 0.75) and SGRQ (r = - 0.79). The reduced questionnaire with 8 activities (from cleaning to climbing stairs) and 3 modalities (slowly, seeking help, changing habits) showed a comparable validity and was chosen as the final short version. Effect size of rehabilitation was good for both the full (0.57) and short (0.51) versions. A significant correlation was also found between changes of SGRQ and DYSLIM post rehabilitation: r = - 0.68 and r = - 0.60 for full and reduced questionnaires, respectively. CONCLUSION: The DYSLIM questionnaire appears promising for the evaluation of dyspnea-induced limitations in chronic respiratory diseases and seems suitable for use in various contexts.

Additional Effects of Nutritional Antioxidant Supplementation on Peripheral Muscle during Pulmonary Rehabilitation in COPD Patients: A Randomized Controlled Trial.

BACKGROUND: Skeletal muscle dysfunction in patients with chronic obstructive pulmonary disease (COPD) is not fully reversed by exercise training. Antioxidants are critical for muscle homeostasis and adaptation to training. However, COPD patients experience antioxidant deficits that worsen after training and might impact their muscle response to training. Nutritional antioxidant supplementation in combination with pulmonary rehabilitation (PR) would further improve muscle function, oxidative stress, and PR outcomes in COPD patients. METHODS: Sixty-four COPD patients admitted to inpatient PR were randomized to receive 28 days of oral antioxidant supplementation targeting the previously observed deficits (PR antioxidant group; α-tocopherol: 30 mg/day, ascorbate: 180 mg/day, zinc gluconate: 15 mg/day, selenomethionine: 50 µg/day) or placebo (PR placebo group). PR consisted of 24 sessions of moderate-intensity exercise training. Changes in muscle endurance (primary outcome), oxidative stress, and PR outcomes were assessed. RESULTS: Eighty-one percent of the patients (FEV1 = 58.9 ± 20.0%pred) showed at least one nutritional antioxidant deficit. Training improved muscle endurance in the PR placebo group (+37.4 ± 45.1%, p < 0.001), without additional increase in the PR antioxidant group (-6.6 ± 11.3%; p = 0.56). Nevertheless, supplementation increased the α-tocopherol/γ-tocopherol ratio and selenium (+58 ± 20%, p < 0.001, and +16 ± 5%, p < 0.01, respectively), muscle strength (+11 ± 3%, p < 0.001), and serum total proteins (+7 ± 2%, p < 0.001), and it tended to increase the type I fiber proportion (+32 ± 17%, p = 0.07). The prevalence of muscle weakness decreased in the PR antioxidant group only, from 30.0 to 10.7% (p < 0.05). CONCLUSIONS: While the primary outcome was not significantly improved, COPD patients demonstrate significant improvements of secondary outcomes (muscle strength and other training-refractory outcomes), suggesting a potential "add-on" effect of the nutritional antioxidant supplementation (vitamins C and E, zinc, and selenium) during PR. This trial is registered with NCT01942889.

Heterogeneity of Systemic Oxidative Stress Profiles in COPD: A Potential Role of Gender.

Oxidative stress (OS) plays a key role in the muscle impairment and exercise capacity of COPD patients. However, the literature reveals that systemic OS markers show great heterogeneity, which may hinder the prescription of effective antioxidant supplementation. This study therefore aimed to identify OS markers imbalance of COPD patients, relative to validated normal reference values, and to investigate the possibility of systemic OS profiles. We measured systemic enzymatic/nonenzymatic antioxidant and lipid peroxidation (LP) levels in 54 stable COPD patients referred for a rehabilitation program. The main systemic antioxidant deficits in these patients concerned vitamins and trace elements. Fully 89% of the COPD patients showed a systemic antioxidant imbalance which may have caused the elevated systemic LP levels in 69% of them. Interestingly, two patient profiles (clusters 3 and 4) had a more elevated increase in LP combined with increased copper and/or decreased vitamin C, GSH, and GPx. Further analysis revealed that the systemic LP level was higher in COPD women and associated with exercise capacity. Our present data therefore support future supplementations with antioxidant vitamins and trace elements to improve exercise capacity, but COPD patients will probably show different positive responses.

Blunted muscle angiogenic training-response in COPD patients versus sedentary controls.

The impaired skeletal muscle of chronic obstructive pulmonary disease (COPD) patients reduces exercise capacity. Similar to the oxidative muscle fibres, the angio-adaptation of muscle to training may be blunted in these patients, as in other chronic conditions. We therefore compared muscle functional responses and angio-adaptations after training in COPD patients and sedentary healthy subjects (SHS). 24 COPD patients (forced expiratory volume in 1 s 45.6 ± 17.5% predicted) and 23 SHS (<150 min · week(-1) of moderate-to-vigorous exercise) completed a 6-week rehabilitation programme based on individualised moderate-intensity endurance training. Histomorphological muscle analysis and measurements of pro-angiogenic vascular endothelial growth factor (VEGF)-A and anti-angiogenic thrombospondin (TSP)-1 were conducted before and after training. COPD patients and SHS showed improved symptom-limited oxygen consumption and muscle endurance, although improvements were lower in COPD patients (+0.96 ± 2.4 versus +2.9 ± 2.6 mL · kg(-1) · min(-1), p<0.05, and +65% versus +108%, p = 0.06, respectively). The capillary-to-fibre (C/F) ratio increased less in COPD patients than SHS (+16 ± 10% versus +37 ± 20%, p<0.05) and no fibre type switch occurred in COPD patients. The VEGF-A/TSP-1 ratio increased in COPD patients and SHS (+65% versus +35%, p<0.05). Changes in C/F and symptom-limited oxygen consumption were correlated (r = 0.51, p<0.05). In addition to a lack of fibre switch, COPD patients displayed a blunted angiogenic response to training.