Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease: Predictors of Program Completion and Success

Figures & data

Table 1.  Patient characteristics

N	814
Age, year (SD)	67.62 (10.45)
Minimum	33
Maximum	91
Female, n (%)	410 (50.40)
Height, cm (SD)	165.41 (9.57)
Weight, kg (SD)	77.46 (22.13)
BMI, kg/m2	28.29 (7.87)
Smoking history, pack years (SD)	43.33 (21.17)
Co-morbid illness, n (%)
Asthma	122 (15.00)
Diabetes	114 (14.00)
Hypertension	315 (38.70)
Coronary artery disease	117 (14.40)
Dyslipidemia	226 (27.80)
Musculoskeletal	87 (10.70)
Chronic heart failure	41 (5.00)
Lung function, mean (SD)
FEV1,% predicted	49.67 (21)
FVC,% predicted	72.67 (21)
FEV1/FVC	0.67 (0.19)
TLC,% predicted	115 (28)
RV,% predicted	166 (73)
DLCO,% predicted	60 (32)
Exercise
12-minute walk, m	638.34 (226.54)
VO2peak, ml/kg	16.56 (4.69)

Note. FEV1 = forced expiratory volume in 1 second, FVC = forced vital capacity. TLC = total lung capacity, RV = residual volume, DLCO = diffusion capacity for carbon monoxide.

Table 2.  Characteristics of program completers and drop-outs

Variable	Completers	Drop-outs	F-value	P-value
N	678	136
Age, year (SD)	68.53 (9.63)	63.13 (12.95)	31.32	.000*
Sex,% female	44	56	2.55	.110
FEV1,% predicted	50.44 (20.78)	45.83 (21.33)	5.51	.019*
FEV1/FVC% predicted	0.68 (0.18)	0.66 (0.19)	0.756	.385
Smoking status,% smoker (N)	26 (178)	49 (67)	29.47	.000*
12 minute walk distance, m	643 (224)	615 (209)	1.88	.171
VO2peak, ml/kg/min	15.57 (5.00)	14.67 (5.10)	3.51	.061
SGRQ total score	46.47 (16.89)	53.98 (18.14)	17.26	.000*
SF-36
Physical Functioning	42.10 (22.99)	34.51 (20.80)	12.72	.000*
Role Physical	35.69 (37.72)	26.94 (31.17)	6.44	.011*
Bodily Pain	62.30 (26.90)	48.86 (24.70)	29.04	.000*
General Health	48.00 (19.70)	42.54 (19.76)	8.71	.003*
Vitality	46.18 (20.30)	37.85 (17.81)	20.30	.000*
Social Functioning	69.14 (26.26)	57.23 (26.23)	23.31	.000*
Role Emotional	54.52 (41.5)	42.80 (37.33)	9.16	.003*
Mental Health	69.68 (18.36)	62.81 (20.44)	15.25	.000*

Note. FEV1 = Forced expiratory volume in 1 second, FVC = Forced vital capacity, SGRQ = St. George respiratory questionnaire, SF-36 = Short Form Health Survey.

Table 3.  Predictor variables of discriminant function analysis for completers and drop-outs

Variable	Coefficient
Age	0.649
Bodily Pain	0.625
Social Functioning	0.560
Vitality	0.522
Mental Health	0.453
Smoker	0.441
Total SGRQ	–0.439
Physical Functioning	0.413
Role Emotional	0.351
General Health	0.342

Note. The rest of the variables had function coefficients too small to be notable.

Table 4.  St. George's Respiratory Questionnaire (SGRQ), 12-minute walk distance, and Short Form Health Survey (SF-36) Pre- and Post-Pulmonary Rehabilitation

	Pre-PR	Post-PR
	M (SD)	M (SD)	p-value	h2
N = 676
SGRQ Total	46.42 (16.86)	41.92 (16.91)	.000	.17
12MWD	641.92 (222.21)	739.99 (231.28)	.000	.30
SF-36			.050	.01
Physical	49.03 (2.18)	49.08 (2.45)	.563	.00
Mental	48.59 (5.49)	48.85 (6.88)	.260	.00

Note. M = mean, SD = standard deviation, 12MWD = 12-minute walk distance.