Survival following pulmonary rehabilitation in patients with COPD: the effect of program completion and change in incremental shuttle walking test distance

Figures & data

Table 1 Patient demographics at baseline pulmonary rehabilitation assessment

Mean (SD) unless otherwise stated	n=1,515
Age at assessment (years)	69.10 (9.10)
Gender % (male/female)	60%/40%
FEV1 (L)	1.14 (0.53)
% predicted FEV1	47.25 (21.51)
FVC (L)	2.41 (2.92)
Home oxygen use, total (n)	228
PRN (n)	112
LTOT (n)	116
BMI (kg/m^2)	26.96 (6.13)
MRC dyspnea grade	3.51 (1.04)
Grade 2 (%)#	16.7
Grade 3 (%)#	26.0
Grade 4 (%)#	25.6
Grade 5 (%)#	17.6
Pack years smoked	43.92 (26.51)
ISWT distance (meters)	199.40 (134.99)
GOLD stage I (%)#	0.1
GOLD stage II (%)#	3.8
GOLD stage III (%)#	24.5
GOLD stage IV (%)#	53.3

Notes:

# Percentages do not add up to 100%; 18.2% of patients could not be classified into GOLD stage due to missing data for either FEV₁, FVC, age or height; 14.1% missing data for MRC grade.

Abbreviations: PRN, pro re nata (as and when); LTOT, long-term oxygen therapy; BMI, body mass index; MRC, Medical Research Council; ISWT, incremental shuttle walking test; GOLD, Global initiative for chronic Lung Disease.

Table 2 Baseline variables for those patients who completed and did not complete pulmonary rehabilitation

Baseline mean (SD) unless otherwise stated	Completed PR n=823 (54.3%)	Did not complete PR n=692 (45.7%)	p-value
Age at assessment (years)	69.70 (8.57)	68.39 (9.65)	0.05*
Men, n (%)	495 (60.15%)	414 (59.83%)	NS
Women, n (%)	328 (39.85%)	278 (40.17%)	NS
FEV1 (L)	1.14 (0.53)	1.14 (0.52)	NS
% predicted FEV1	47.06 (22.35)	47.40 (20.79)	NS
Home oxygen use, n (%)	115 (13.97%)	113 (16.33%)	NS
BMI (kg/m^2)	27.30 (6.19)	26.53 (6.03)	NS
MRC grade median (IQR)	4.0 (1)	3.0 (1)	<0.001*
ISWT (meters)	216.28 (128.91)	179.30 (139.35)	<0.001**

Notes:

* Significant at p<0.05;

** significant at p<0.001.

Abbreviations: PR, pulmonary rehabilitation; BMI, body mass index; MRC, Medical Research Council; IQR, interquartile range; ISWT, incremental shuttle walking test; NS, not significant.

Figure 1 Kaplan Meir survival analysis for “completers” and “non-completers” of PR.

Note: Significant at p<0.001, log rank test.

Abbreviation: PR, pulmonary rehabilitation.

Figure 2 Kaplan Meir survival analysis for “responders” and “non-responders” in exercise training.

Note: Significant at p<0.001, log rank test.

Table 3 Results of Cox regression analysis to identify factors that independently predict mortality, including completion of a pulmonary rehabilitation program

	B	Exponential (95% CI) for B	p-value
Age at assessment#	<0.001	1.000 (1.00)	<0.001**
Pack years smoked	0.002	1.002 (0.909–1.007)	0.346
Gender	0.237	1.267 (0.998–1.609)	0.052
MRC grade (pre-PR)	0.193	1.213 (1.066–1.381)	0.003*
BMI	−0.023	0.977 (0.957–0.999)	0.036*
ISWT (pre-PR)	−0.003	0.997 (0.996–0.998)	<0.001**
% predicted FEV1	−0.010	0.990 (0.979–1.002)	0.103
Home oxygen use	−0.303	0.738 (0.558–0.978)	0.034*
Completion of PR	0.455	1.560 (1.238–1.967)	<0.001**

Note:

# Age at assessment as a time dependent covariable,

* significant at p<0.05,

** significant at p<0.001.

Abbreviations: MRC, Medical Research Council; PR, pulmonary rehabilitation; BMI, body mass index; ISWT, incremental shuttle walking test.

Table 4 Results of Cox regression analysis to identify factors that independently predict mortality, including magnitude of change in exercise capacity (∆ISWT), for patients who completed pulmonary rehabilitation

	B	Exponential (95% CI) for B	p-value
Age at assessment#	<0.001	1.000 (1.000)	0.003**
Pack years smoked	0.002	1.002 (0.996–1.009)	0.473
Gender	0.186	1.204 (0.866–1.673)	0.269
MRC grade (pre-PR)	0.164	1.178 (0.980–1.416)	0.081
BMI	−0.065	0.937 (0.907–0.968)	<0.001**
ISWT (pre-PR)	−0.003	0.997 (0.995–0.998)	<0.001**
% predicted FEV1	−0.021	0.979 (0.961–0.997)	0.026*
Home oxygen use	−0.014	0.986 (0.658–1.476)	0.944
ΔISWT (pre- to post-PR)	−0.003	0.996 (0.994–0.998)	0.018*

Note:

# Age at assessment as a time dependent covariable,

* significant at p<0.05,

** significant at p<0.001.

Abbreviations: MRC, Medical Research Council; PR, pulmonary rehabilitation; BMI, body mass index; ISWT, incremental shuttle walking test.