Determinants of each domain of the Short Physical Performance Battery in COPD

Figures & data

Table 1 Descriptive characteristics

Descriptive characteristics	Mean ± SD or number (%)	Range
Health-related
Age (years)	66.9±8.3	46–80
Dyspnea (mMRC) ≥2	49 (35.8)	N/A
BMI	28.9±5.1	16.7–46
Physical activity (METs/14 days)	4,206.8±5,285.6	0–27,389.9
COPD assessment (CAT score)	14.19±7.32	1–39
Functional status
Pulmonary function (FEV1 %)	50.2±16.5	17–102
Exercise tolerance (6MWT, m)	349.1±84.7	54–570
Quadriceps strength (kg)	31.37±5.74	17.9–44.9
Psychological status
HADS score (depression scale) ≥8	26 (19)	N/A
SPPB subscales
5STS test (in seconds)	14.2±3.2	6.9–28.5
4MGS test (in seconds)	4.7±2.7	2.5–33
Balance test	3.7±0.7	0–4

Abbreviations: mMRC, modified Medical Research Council Dyspnea Scale; BMI, body mass index; METs, metabolic energy turnover; CAT, COPD assessment test; FEV₁, forced expiratory volume in 1 s; 6MWT, 6-min walk test; HADS, Hospital Anxiety and Depression Scale; 5STS, five-repetition sit-to-stand; 4MGS, 4 m gait speed; SPPB, Short Physical Performance Battery; N/A, not applicable.

Table 2 Final multivariable linear regression models

Functional measure	Independent variable	Estimate	Standard error	B standardized	P-value	Model R^2	Partial R^2
4MGS	Age (years)	0.033	0.011	0.247	0.003	0.310	0.049
	Exercise tolerance (6MWT, m)	−0.003	0.001	−0.260	0.002		0.052
	Quadriceps strength (kg)	−0.032	0.015	−0.172	0.034		0.024
	HADS >8 (depression scale)	0.515	0.213	0.183	0.017		0.032
5STS	Age (years)	0.084	0.031	0.218	0.007	0.391	0.040
	CAT score	0.134	0.036	0.279	0.000		0.073
	Exercise tolerance (6MWT, m)	−0.010	0.003	−0.263	0.002		0.056
	Quadriceps strength (kg)	−0.140	0.043	−0.251	0.001		0.056

Abbreviations: 6MWT, 6-min walk test; HADS, Hospital Anxiety and Depression Scale; CAT, COPD assessment test; 5STS, five-repetition sit-to-stand; 4MGS, 4 m gait speed.