Comparison of 3-minute Step Test (3MStepT) and 6-minute Walk Test (6MWT) in Patients with COPD

Figures & data

Table 1. Demographic, clinical and initial spirometric data of patients with COPD.

Number	50
Gender (F/M) (n, %)	17 (34%)/33 (66%)
Age	62.3 ± 7.9
Height (cm)	166.9 ± 7.7
Weight (kg)	75.1 ± 18.9
BMI (kg/ m^2)	27.1 ± 6.6
FEV1 (%pred)	45.2 ± 18.3
FEV1/ FVC (%)	48.0 ± 12.4
IC (l)	2.20 ± 0.76
TLC (%pred)	108.1 ± 33.6
RV/TLC (%)	142.0 ± 30.9
GOLD 2/3/ 4 (n)	18/23/9
mMRC	2.0 ± 1.26
SGRQ (total)	50.7 ± 17.1
HAD-A	8.7 ± 4.6
HAD-D	6.1 ± 4.0
BODE index	3.5 ± 2.0
PI max (cm H2O)	69.1 ± 24.8
6MWT (%pred)	67.6 ± 14.4
6MWD (m)	432.6 ± 96.3
3MstepT	62.1 ± 18.0

Values are expressed as mean ± standard deviation or median [interquartile range][Q1–Q3] or number.

BMI, body mass index; cm: centimeter; FEV1, forced expiratory volume in 1 s; F, female; FVC, forced vital capacity; HAD-A, hospital anxiety and depressive scale-anxiety; HAD-D, hospital anxiety and depressive scale-depression; IC, inspiratory capacity; kg, kilogram; M, male; m, meter; mMRC, Modified Medical Research Council; n, number; PImax: maximal inspiratory pressure; pred, predictive value; RV, residual volume; SGRQ, Saint-George Respiratory Questionnaire; 6MWT, 6-minute walk test; 3MstepT, 3-minute step test; TLC, total lung volume.

Table 2. Comparison of cardiorespiratory variables at the end of 6MWT and 3MstepT.

	6MWT	3MstepT	P-value	Coefficient of correlation with CI95%
HR (n/min)	106.2 ± 16.3 [101,5–110,5]	112.9 ± 13.4 [109,4–116,9]	0.002	0.50 [0.184–0.756], p < .001
Delta HR (HR end of the test–HR start of the test)	19.3 ± 8.1 [17.0–21.6]	23.6 ± 11.4 [20.3–26.8]	0.019	0.31 [0.026–0.536], p = 0.037
SpO2 (%)	87.6 ± 5.4 [86,1–89,0]	89.6 ± 5.3 [88,1–91,1]	0.001	0.69 [0.406–0.850], p < .001
Delta SpO2 (SpO2 end of the test—SpO2 start of the test)	–6.4 ± 4.6 [–7.7 to –5.2]	–4.8 ± 4,2 [–6.0 to –3.7]	0.004	0.66 [0.447–0.810], p < .001
Dyspnea (Borg)	4.9 ± 2.4 [4,2–5,5]	5.0 ± 2.2 [4,4–5,6]	0.62	0.56 [0.295–0.765], p < .001
Lower limb fatigue (Borg)	2.5 ± 2.6 [1,8–3,2]	3.4 ± 2.4 [2,7–4,1]	0.01	0.52 [0.246–0.756], p < .001

Values are expressed as mean ± standard deviation, with 95% confidence interval in brackets.

6MWT, 6-minute walk test; 3MstepT, 3-minute step Test; HR, heart rate; n, number; min, minute; SpO2, oxygen pulsed oximetry.

Figure 1. Repeatability of 3MstepT illustrated by the Bland–Altman plots, including bias and limits of agreement.