Clinical impact of time of day on acute exercise response in COPD.

The purpose of this pilot study was to determine the impact of time of day on the acute response to incremental exercise in chronic obstructive pulmonary disease (COPD). Fourteen subjects (nine men) aged 71 ± 7 years with moderate to severe airflow obstruction (FEV1: 58 ± 13% predicted) followed a counterbalanced randomized design, performing three symptom-limited incremental cycling tests at 8:00, 12:00, and 16:00 hours on different days, each preceded by a spirometry. COPD medications were withdrawn prior to testing. No overall time effect was found for peak exercise capacity (p = 0.22) or pulmonary function (FEV1, p = 0.56; FVC, p = 0.79). However, a large effect size (f = 0.48) was observed for peak exercise capacity and several pulmonary function parameters. For peak exercise capacity, the average within-subject coefficient of variation was 5.5 ± 3.9% and the average amplitude of change was 7 ± 5W. Seven subjects (50%) showed diurnal changes at levels equal to or beyond the minimal clinically important difference for both peak exercise capacity and pulmonary function. In this sub-group, peak exercise capacity was greatest at 16:00 hours (p = 0.03, ƒ = 1.04). No systematic time-of-day effect on peak exercise capacity was obtained in COPD patients in the present pilot study. However, based on the observed effect size and on the average amplitude of change and within-subject variations seen across testing times, the guidelines recommendation that time of day be standardized for repeat exercise testing in COPD should be maintained.

Effects of home-based pulmonary rehabilitation in patients with chronic obstructive pulmonary disease: a randomized trial.

BACKGROUND: Home-based rehabilitation is a promising approach to improve access to pulmonary rehabilitation. OBJECTIVE: To assess whether self-monitored, home-based rehabilitation is as effective as outpatient, hospital-based rehabilitation in patients with chronic obstructive pulmonary disease (COPD). DESIGN: Randomized, multicenter, noninferiority trial. SETTING: 10 academic and community medical centers in Canada. PATIENTS: 252 patients with moderate to severe COPD. INTERVENTION: After a 4-week education program, patients took part in home-based rehabilitation or outpatient, hospital-based rehabilitation for 8 weeks. They were followed for 40 weeks to complete the 1-year study. MEASUREMENTS: The primary outcome was the change in Chronic Respiratory Questionnaire dyspnea subscale score at 1 year. The primary analysis took a modified intention-to-treat approach by using all patients who provided data at the specified follow-up time, regardless of their level of adherence. The analysis used regression modeling that adjusted for the effects of center, sex, and baseline level. All differences were computed as home intervention minus outpatient intervention. RESULTS: Both interventions produced similar improvements in the Chronic Respiratory Questionnaire dyspnea subscale at 1 year: improvement in dyspnea of 0.62 (95% CI, 0.43 to 0.80) units in the home intervention (n = 107) and 0.46 (CI, 0.28 to 0.64) units in the outpatient intervention (n = 109). The difference between the 2 treatments at 1 year was small and clinically unimportant. The 95% CI of the difference did not exceed the prespecified noninferiority margin of 0.5: difference in dyspnea score of 0.16 (CI, -0.08 to 0.40). Most adverse events were related to COPD exacerbations. No serious adverse event was considered to be related to the study intervention. LIMITATION: The contribution of the educational program to the improvement in health status and exercise tolerance cannot be ascertained. CONCLUSION: Home rehabilitation is a useful, equivalent alternative to outpatient rehabilitation in patients with COPD.

Mild cognitive impairment in moderate to severe COPD: a preliminary study.

BACKGROUND: Cognitive impairment is a frequent feature of COPD. However, the proportion of patients with COPD with mild cognitive impairment (MCI) is still unknown, and no screening test has been validated to date for detecting MCI in this population. The goal of this study was to determine the frequency and subtypes of MCI in patients with COPD and to assess the validity of two cognitive screening tests, the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA), in detecting MCI in patients with COPD. METHODS: Forty-five patients with moderate to severe COPD and 50 healthy control subjects underwent a comprehensive neuropsychologic assessment using standard MCI criteria. Receiver operating characteristic curves were obtained to assess the validity of the MMSE and the MoCA to detect MCI in patients with COPD. RESULTS: MCI was found in 36% of patients with COPD compared with 12% of healthy subjects. Patients with COPD with MCI had mainly the nonamnestic MCI single domain subtype with predominant attention and executive dysfunctions. The optimal MoCA screening cutoff was 26 (≤ 25 indicates impairment, with 81% sensitivity, 72% specificity, and 76% correctly diagnosed). No MMSE cutoff had acceptable validity. CONCLUSIONS: In this preliminary study, a substantial proportion of patients with COPD were found to have MCI, a known risk factor for dementia. Longitudinal follow-up on these patients is needed to determine the risk of developing more severe cognitive and functional impairments. Moreover, the MoCA is superior to the MMSE in detecting MCI in patients with COPD.