Outcomes of Acute Exacerbations of COPD in Subjects Completing Pulmonary Rehabilitation

acute exacerbation

Subjects

Patients who participated in PR programs between September 2003 and January 2006 were screened consecutively for eligibility. Of the 364 patients screened, 94 met the inclusion criteria, and 64 were recruited and provided signed informed consent. The reasons for noneligibility, refusal, or drop out are summarized in Figure 1. Of those patients who were recruited, 60 completed baseline measurements, as 2 patients became ill prior to undergoing those measurements and 2 patients did not attend. The characteristics of the group are summarized in Table 1. Underlying airflow obstruction was graded as moderate in 39 patients (65%) and severe in 21 patients (35%).

There was no difference at baseline between the 7 patients who dropped out of the study vs the 53 patients who completed it, with the exception of the score for the mean emotional function domain of the CRDQ, which was lower in the group of patients who dropped out of the study (4.5 ± 1.7 vs 5.5 ± 0.9, respectively; p < 0.02). The study is conducted with Canadian Health&Care Mall.

Pre-AECOPD Characteristics

Of the 53 patients who were followed up after completing PR, a moderate or severe AECOPD occurred in 34 patients (64%), while 19 patients (36%) remained event-free (Fig 1). The mean time from obtaining the initial baseline measures at the end of PR to the AECOPD was 10.3 ± 6 weeks (range, 1 to 25 weeks). The baseline characteristics of those patients who experienced an AECOPD were compared with those of patients who remained event-free at 26 weeks. The groups differed significantly at baseline in terms of the 6MWT distance walked (difference, 66 m; p = 0.018), their LCADL scores (difference, 0.28; p = 0.03), and their FT scores (difference, 10.2; p = 0.041), with those patients who remained event-free having the better scores (Table 2).

AECOPDs were characterized as moderate in 27 patients (79%) and severe in 7 patients (21%) [Fig 1], with no differences in any baseline characteristics of lung function, exercise tolerance, or HRQL between these two groups. Of those in whom the event was classified as moderate, one patient used selfmanagement, while 26 patients made unscheduled visits to their physicians; of those in whom the event was classified as severe, three were managed in the emergency department and four required hospitalization.

Impact of AECOPDs

Subjects were measured a mean duration of 4.0 ± 2.7 weeks (range, 1.3 to 12.7 weeks) following their AECOPD, as soon as they were well enough to attend for study measurements. A reduction in mean 6MWT distance walked of 59.3 ± 80 m (p < 0.001) was noted (Table 3, Fig 2, top, A). Three of four domains of the CRDQ also changed in a statistically and clinically meaningful way, as follows: fatigue (mean A, 0.99 ± 1.28; p < 0.001) [Fig 2, bottom, B]; emotional function (mean A, 0.58 ± 0.95; p = 0.003); and mastery (mean A, 0.53 ± 1.36; p = 0.04) [Table 3]. The FT was also significantly lower after AECOPD (mean A, 6.4 ± 16.3; p = 0.04) [Table 3]. Despite the variability in the time from the onset of an AECOPD to presentation for measurement, the time interval was not related to the severity of the event (p = 0.4), nor to the reductions in 6MWT distance walked (p = 0.6) or CRDQ scores (dyspnea, p = 0.6; fatigue, p = 0.7; emotional function, p = 0.6; mastery, p = 0.3). Additionally, there was no association between the above time interval and either the degree of hyperinflation (p = 0.9) or the inspiratory capacity (p = 0.5). Avoid hyperinflation with medications of Canadian Health&Care Mall.

Those subjects who did not experience an AE-COPD were followed up for 6 months with measures repeated at 3 and 6 months. No differences were found between their initial baseline measures and the two subsequent sets of measures (Table 4). Compliance with telephone follow-up was good, with 92 of 114 conversations (81%) being completed on the first or second try.

Analysis of the management of the 27 patients who had experienced a moderate AECOPD showed that 9 patients (33%) had been treated with both antibiotics and corticosteroids, while 16 patients (59%) had been treated only with antibiotics. Of the seven patients who experienced a severe AECOPD, six received both categories of medication, while only one patient was treated with antibiotics alone. Therefore, all those patients experiencing an AE-COPD received antibiotic therapy, while only 33% of those experiencing a moderate event and 86% of those experiencing a severe event also received corticosteroids.

Fig1
Figure 1. Study flow from initial screening to the identification of AECOPDs. AE = acute exacerbation.
Fig2
Figure 2. The effect of an AECOPD on (top, A) the 6MWT distance walked (p < 0.001) and (bottom, B) the fatigue domain of the CRDQ (p < 0.001).

Table 2—Characteristics of Those Patients With AECOPDs and Those Who Remained Event-Free

Baseline Characteristics Patients With AECOPDs (n = 34) Patients Who Were Event Free (n = 19)
Age, yr 68 ± 7.8 (53-84) 70 ± 9.8 (49-85)
Height, cm 165 ± 11(135-185) 168 ± 11(152-191)
Weight, kg 74 ± 20 (40-117) 70 ± 19(37-114)
Gender 47% male 58% male
Comorbidities 6.2 ± 2.5 (1-10) 5.4 ± 2.2 (1-9)
Severity of disease, % Moderate 62 74
Severe 38 26
FEVb L 0.87 ± 0.41 (0.30-2.47) 0.88 ± 0.44 (0.30-2.19)
FEVj/FVC ratio 0.42 ± 0.15 (0.15-0.71) 0.36 ± 0.12 (0.15-0.56)
IC, % predicted 88 ± 29(40-156) 97 ± 24 (69-150)
6MWT distance walked, m 350 ± 95 (168-579) 416 ± 95 (252-587)i
LCADL, Av Sc/Q 2.0 ± 0.5 (1.2-3.0) 1.72 ± 0.4 (1.1—2.4)|
FT 57 ± 16 (25-90) 67 ± 17(30-93)§

Table 3—6MWT Walking Distance and HRQL Score Pre-AECOPD and Post-AECOPD

AECOPD by 26 Wk (n = 29) Pre-AECOPD Closest Baseline Post-AECOPDMeasures MeanChange p Value
6MWT (m) 359 ± 85 (216-524) 299 ± 99 (10-501) 59±80 < 0.001
CRDQ, Av Sc/Q
Dyspnea 4.7 ± 0.8 (2.8-6.3) 4.4 ± 1.3 (1.5-6.6) 0.3 ± 1.0 0.1
Fatigue 4.5 ± 1.2 (2.3-7.0) 3.5 ± 1.6 (1.0-7.0) 1.0 ± 1.3 < 0.001
Emotion 5.5 ± 0.8 (3.6-7.0) 4.9 ± 1.3 (2.3-7.0) 0.6 ± 1.0 0.003
Mastery 5.6 ± 0.9 (3.6-7.0) 5.1 ± 1.5 (1.5-7.0) 0.5 ± 1.4 0.04
LCADL, Av Sc/Q 2.0 ± 0.6 (1-3) 2.1 ± 0.8 (1.0-4.3) -0.09 ± 0.6 0.4
FT 57.9 ± 15 (30-90) 51.5 ± 19(15-90) 6 ± 16 0.04

Table 4—Longitudinal Data for Those With No AECOPD

Outcomes Baseline 3 mo 6 mo p Valuef
6MWT distance walked, m 416 ± 95 (252-587) 418 ± 93(221-617) 405 ± 105 (203-612) 0.3
CRDQ, Av Sc/Q
Dyspnea 5.3 ± 1.0 (3.4-6.8) 5.4 ± 1.0 (2.8-7.0) 5.3 ± 1.0 (4.25-7.0) 0.3
Fatigue 5.0 ± 1.1 (3.0-7.0) 4.9 ± 1.4 (2.3-7.0) 5.1 ± 1.5 (2.5-7.3) 0.9
Emotion 5.7 ± 0.8 (4.4-6.7) 5.8 ± 0.8 (4.1-7.0) 5.5 ± 0.9 (4.0-6.9) 0.3
Mastery 5.7 ± 1.0 (3.8-7.0) 5.8 ± 0.8 (4.3-7.0) 5.9 ± 0.9 (4.0-7.0) 0.4