Magnitude of exercise capacity and quality of life improvement following repeat pulmonary rehabilitation in patients with COPD

Figures & data

Table 1 Patient demographics obtained immediately prior to commencing PRP1 and prior to each subsequent program (PRP2 and PRP3)

Variable	PRP1 (n=141)	PRP2 (n=141)	PRP3 (n=35)
Age (years)	68±7	71±7	72±7
Male (%)	56	56	64
Home oxygen use (%)	15	19	25
BMI (kg/m^2)	26±5	26±6	25±5
FEV1 (L)	1.02±0.42	0.91±0.40*	0.84±0.38*,#
FEV1 (% predicted)	42±17	39±16*	35±16*
FVC (% predicted)	80±20	75±18	77±19
6MWD (m)	411±87	373±106*	374±97*
SGRQ total (units)	54±16	56±14§	56±10§
HADS total (units)	13 (8–18)	12 (8–18)	11.5 (7–15)
HADS anxiety (units)	7 (5–10)	7 (4–10)	6 (4–9.75)
HADS depression (units)	5 (3–8)	6 (3.5–9)	5 (3–7)
Current smokers (%)	10	8	2
Smoking (pack-years)	43±23	46±21	41±19
Time between PRP (months)	N/A	34±20	29±15

Notes: Data are shown as mean ± SD apart from HADS and its anxiety and depression domains, which are shown as median values (interquartile range).

* P<0.0001 vs PRP1;

§ P<0.05 vs PRP1;

# P<0.001 vs PRP2; linear mixed effects.

Abbreviations: BMI, body mass index; FEV₁, forced expiratory volume in 1 second; FVC, forced vital capacity; HADS, Hospital Anxiety and Depression Scale (0–22, 0= no symptoms of anxiety or depression); N/A, not available; PRP, pulmonary rehabilitation program; SD, standard deviation; SGRQ, St George’s Respiratory Questionnaire (0–100 units, 0 units = best quality of life); 6MWD, 6-minute walk distance.

Figure 1 Grouped column graph of mean 6MWD pre-PRP (black) vs post-PRP (gray) for each PRP session.

Notes: n=141 for PRP sessions 1 and 2, and n=35 for session 3. Error bars represent standard deviations. Mean improvement was 58 m following PRP1, 42 m following PRP2, and 32 m following PRP3. All PRP sessions resulted in improvement in 6MWD (P<0.0005 for 6MWD post vs pre), although there was less improvement in PRP2 compared with PRP1 (P=0.03).
Abbreviations: PRP, pulmonary rehabilitation program; 6MWD, 6-minute walk distance.

Figure 2 Grouped column graph of mean SGRQ pre-PRP (black) vs post-PRP (gray) for each PRP session.

Notes: Error bars represent standard deviations. Mean improvement was 7.0 units after PRP1 and 4.9 units after PRP2. There were significant reductions in SGRQ following PRP1 and PRP2 (P<0.001) but not after PRP3 (P=0.10).

Abbreviations: PRP, pulmonary rehabilitation program; SGRQ, St George’s Respiratory Questionnaire.

Figure 3 Grouped column graph of mean HADS pre-PRP (black) vs post-PRP (gray) for each PRP session.

Notes: Error bars represent standard deviations. Mean HADS improved more than the MCID only following PRP1 and PRP2 (−1.9 and −1.7 units, respectively; P<0.001; linear mixed effects) but not after PRP3 (P=0.63).
Abbreviations: HADS, hospital anxiety and depression scale; MCID, minimal clinical important difference; PRP, pulmonary rehabilitation program.

Table 2 Effect of interval between pulmonary rehabilitation programs on 6MWD and quality of life measures for 141 patients

	Interval between PRP1 and PRP2			P-value
	0–2 years	2–4 years	>4 years
Number of subjects	58	58	25
∆6MWD (m)	47±66	38±45	39±53	0.72
∆SGRQ (units)	−6±11	−2±11	−10±13*	0.008
∆HADS (units)	−2.0±6.1	−1.2±4.8	−2.4±5.1	0.57

Notes: Groups divided by time interval between first pulmonary rehabilitation program (PRP1) and repeat pulmonary rehabilitation program (PRP2), measured from the date of the last exercise session from PRP1 to the first exercise session of PRP2. P-values represent one way ANOVA between groups.

* P=0.006 for >4 years vs 2–4 years for SGRQ (one-way ANOVA, Tukey’s post hoc analysis).

Abbreviations: ANOVA, analysis of variance; HADS, Hospital Anxiety and Depression Scale; PRP, pulmonary rehabilitation program; SGRQ, St George’s Respiratory Questionnaire; 6MWD, 6-minute walk distance.