A Simple Clinical Measure of Quadriceps Muscle Strength Identifies Responders to Pulmonary Rehabilitation

Table 1

Baseline assessment data for responders compared to nonresponders in the six minute walk distance.

	(A) Responders	(A) Nonresponders		(B) Responders	(B) Nonresponders
Number (%)	49 (57.6%)	36 (42.4%)		19 (22.4%)	66 (77.6%)
Age (years)	68.0±8.6	66.7±9.7	𝑃=0.523	68.3±8.1	67.2±9.5	𝑃=0.628
FEV1% predicted	57.0±23.3	53.3±21.3	𝑃=0.458	62.8±26.6	53.2±20.6	𝑃=0.101
mMRC	1.6±1.1	1.7±0.9	𝑃=0.964	1.8±1.1	1.6±1.0	𝑃=0.570
Quadriceps strength (%)	57.5±21.9	68.6±21.9	𝑃=0.025	48.1±16.5	66.2±22.4	𝑃=0.002
Physical activity level (METs)^+	1.49±0.18	1.54±0.22	𝑃=0.443	1.45±0.15	1.52±0.20	𝑃=0.307
Interleukin-8 (pg/mL)*	151±434	175±485	𝑃=0.818	144±370	167±478	𝑃=0.856
C Reactive Protein (pg/mL)*	7217±13805	10771±10813	𝑃=0.223	9643±18638	8684±10711	𝑃=0.793
COPD self-efficacy score	3.0 ± 0.8	2.6±0.7	𝑃=0.060	2.8±0.5	2.8±0.8	𝑃=0.884
Charlson comorbidity index	1.9 ± 1.1	2.0±1.1	𝑃=0.608	2.3±1.1	1.8±1.1	𝑃=0.126
Metabolic disease	15/49 (31%)	10/36 (28%)	𝑃=0.814	11/19 (31%)	14/66 (28%)	𝑃=0.004
Cardiac disease	13/49 (27%)	12/36 (33%)	𝑃=0.631	5/19 (26%)	20/66 (30%)	𝑃=1.000
Musculoskeletal disease	18/49 (37%)	9/36 (25%)	𝑃=0.346	10/19 (31%)	17/66 (28%)	𝑃=0.048
Baseline 6MWD (m)	393±16	423±17	𝑃=0.202	359±20	420±13	𝑃=0.015

Part (A) responders/non-responders used the criteria of six-minute walk distance (6MWD) ≥25 m. Part (B) responders/non-responders used the criteria of 6MWD ≥61.9 m. Data expressed as the mean ± standard deviation. FEV₁: forced expiratory volume in one second, mMRC: modified Medical Research Council dyspnea scale, and METs: metabolic equivalent of task.
∗Systemic inflammatory markers were assessed in 77 participants.
+Physical activity level was assessed in 46 participants.