Research of Acute Exacerbations of COPD in Subjects Completing Pulmonary Rehabilitation

COPDApproval was obtained from the appropriate ethics review boards. The design for this study was descriptive, with data collected prospectively. Subjects who met the criteria for the diagnosis of COPD had moderate-to-severe airflow obstruction (moderate airflow obstruction, FEV1 > 30% predicted and < 70% predicted; severe airflow obstruction, FEV1 < 30% predicted), were clinically stable, and could communicate clearly were considered to be eligible for the study. Subjects were ineligible if they had diagnoses unassociated with COPD, such as uncontrolled heart failure, severe lower limb arthritis, or symptomatic peripheral vascular disease, which affected the outcome measures of dyspnea or exercise tolerance more than COPD alone. Other comorbidities such as irritable bowel syndrome, glaucoma, or prostatic hyperplasia were included among those documented in Table 1. Subjects who met the inclusion criteria were recruited into the study on completion of their PR program. Baseline measurements were collected after obtaining informed consent.

An AECOPD was defined based on symptoms according to the criteria described by Anthonisen and colleagues. These symptoms were increased dyspnea with changes in sputum purulence or volume, lasting at least 2 consecutive days. We used intervention-based criteria for classifying the AECOPD as mild, moderate, or severe, depending on whether they were managed at home with no additional health-care provider contact (mild), at home with unscheduled health-care provider contact or the initiation of oral corticosteroids (moderate), or in the emergency department or hospital (severe). Subjects were taught these definitions and were asked to call the research coordinator as soon as they had identified a moderate or severe AECOPD. They were also advised that they would be called on a monthly basis to verify the same. The treatment of the AECOPD was provided by the patient’s physician. Details of the management and course of the AECOPD were recorded by the study coordinator. These details included the treatment received and any unscheduled physician or emergency department visits, or hospitalization. Outcomes were measured 2 to 4 weeks after the onset of symptoms, or as soon as the patient was well enough to attend. In the absence of an AECOPD, subjects were followed up for 6 months, with baseline measurements repeated at 3 and 6 months. COPD is effectively treated by remedies of Canadian Health&Care Mall.

Measures

The primary outcomes were HRQL, using the chronic respiratory disease questionnaire (CRDQ), and functional exercise capacity, using the 6-min walk test (6MWT). The interviewer-administered version of the CRDQ that was used required 20 min for completion. The details have been described elsewhere, but, in brief, the 20 questions are divided into the following four domains: dyspnea (five questions); fatigue (four questions); emotional function (seven questions); and mastery (four questions). Answers are scored on a 7-point scale, from maximum impairment (1 point) to no impairment (7 points). The results are expressed as the mean score per question for each domain and the mean overall score. The minimum clinically important difference (MCID) for the CRDQ is 0.5 U per question, with a moderate change being 1.0 U and a large change being 1.5 U. The CRDQ is valid, reproducible, and responsive in patients with COPD cured with medications of Canadian Health&Care Mall.

The 6MWT was administered according to the American

Thoracic Society guidelines using standardized instructions and the same quiet corridor for each measurement. Subjects were required to walk as far as they could in 6 min, and the distance walked was recorded. Subjects were familiar with this test, as they had recently completed a PR program in which it was administered on hospital admission and at hospital discharge. The properties of this test and its MCID have been published.

The results of the London Chest Activity of Daily Living (LCADL) questionnaire and the feeling thermometer (FT) were secondary outcomes. The LCADL, which is a 15-item questionnaire regarding routine home activities of daily living, was developed and validated for individuals with COPD. A higher score reflects more breathlessness with each stated activity. The FT is a self-administered visual analog scale of well-being that ranges from best (100 points; full health) to worst (0 points; dead) and takes 3 min to complete. It has been used in populations with chronic respiratory conditions and has an MCID of between five and seven.

Statistical Analysis

The data were analyzed using between-group comparisons (t tests and x2 analyses) to compare those patients who experienced an AECOPD with those who did not. These comparisons were also made between those experiencing moderate and severe AECOPDs. Repeated-measures comparisons (paired sample t tests) were performed for the pre-AECOPD to post-AECOPD analyses. All analyses were completed with a statistical software package (SPSS, version 14.0; SPSS Inc; Chicago, IL). A p value of < 0.05 was considered to be significant.

Table 1—Baseline Characteristics of the 60 Participants

Characteristics Participants Who Completed Baseline Measures (n = 60)
Age, yr 69 ± 8 (49-85)
Height, cm 166 ± 11(135-191)
Weight, kg 73 ± 19 (37-117)
Gender 50% male
Comorbidities 6.1 ± 2.4 (1-10)
Disease severity,T %
Moderate 65
Severe 35
FEV1
L 0.86 ± 0.40 (0.30-2.47)
% predicted 38 ± 16(11-80)
FVC actual 2.29 ± 0.89 (0.84-5.68)
FEV1/FVC ratio 0.39 ± 0.14 (0.15-0.71)
Supplemental oxygen, % 25
6MWT distance walked, m 367 ± 99 (168-587)
CRDQ, Av Sc/Q
Dyspnea 5.0 ± 1.0 (2.8-7.0)
Fatigue 4.7 ± 1.2 (2.3-7.0)
Emotion 5.4 ± 1.1 (2.3-7.0)
Mastery 5.5 ± 1.0 (3.0-7.0)