Physical inactivity and arterial stiffness in COPD

Figures & data

Figure 1 The augmentation index (AI) is calculated as the difference between the second (P2) and first (P1) systolic peak pressure and is expressed as percentage of the central PP: AI (%) = [(P2−P1)/PP] ×100.

Table 1 Patient characteristics

Age, y	62 (7.5)
Male/female	89/35
BMI, kg/m^2	24.9 (22.4/28.4)
Current smoker, N (%)	27 (22)
Pack years of smoking, N	39 (26.5/60.0)
Systolic BP, mmHg	129 (15.8)
Diastolic BP, mmHg	81 (10.1)
FEV1, %predicted	35 (27.0/65.0)
FVC, %predicted	79 (18.6)
RV, %predicted	179 (125.0/225.0)
TLC, %predicted	115 (24.0)
RV/TLC	56 (13.0)
TLco, %predicted	36 (15.0/55.0)
Antihypertensivum, N (%)	65 (53)
Statin, N (%)	44 (36)
LAMA only, N (%)	8 (7)
LAMA + GC, N (%)	2 (2)
LABA only, N (%)	5 (4)
LABA + GC, N (%)	13 (11)
LAMA + LABA, N (%)	5 (4)
LAMA + LABA + GC, N (%)	69 (56)
Arterial hypertension, N (%)	54 (44)
CVD, N (%)	27 (22)
PAD, N (%)	12 (10)
CRP, mg/L	1.8 (0.9/4.0)
PAL	1.4 (1.3/1.5)
Number of steps per day, N	4,149 (2,498.5/6,679.0)
Augmentation index, %	26 (9.2)

Note: Values are median (quartiles) or mean (SD) unless otherwise stated.

Abbreviations: y, years; BMI, body mass index; BP, blood pressure; FEV₁, forced expiratory volume in 1 second; FVC, forced volume capacity; RV, residual volume; TLC, total lung capacity; TLco, diffusion capacity; LAMA, long-acting muscarinic antagonist; LABA, long-acting beta-agonist; GC, glucocorticoids; CVD, cardiovascular disease; PAD, peripheral artery disease; CRP, c-reactive protein; PAL, physical activity level.

Figure 2 Study flow.

Table 2 Univariate regression analysis of possible predictors for aortic augmentation index

	B	95% confidence interval	P-value
Linear age
Age, y	0.08	−0.14/0.30	0.452
Nonlinear age
Age, y	3.77	0.88/6.67	0.011*
Age × age, y (squared term)	−0.03	−0.05/−0.01	0.013*
Male	−7.12	−10.59/−3.64	<0.001*
BMI, kg/m^2	−0.44	−0.71/−0.17	0.002*
Current smoker, N	−0.05	−4.06/3.95	0.979
Pack years of smoking, N	0.39	−0.03/0.11	0.291
Systolic blood pressure, mmHg	0.16	0.06/0.26	0.003*
Diastolic blood pressure, mmHg	0.33	0.17/0.48	<0.001*
FEV1, %predicted	−0.06	−0.14/0.01	0.089
FVC, %predicted	−0.01	−0.10/0.07	0.772
RV/TLC, %	0.10	−0.02/0.23	0.098
Arterial hypertension, N	−1.56	−4.89/1.77	0.355
CVD, N	−2.33	−6.31/1.65	0.249
PAD, N	−0.06	−5.64/5.53	0.984
CRP, mg/L	0.03	−1.14/0.21	0.699
PAL	−11.72	−19.66/−3.78	0.004*
Number of steps per day, N	−0.00	−0.00/0.00	0.502

Note:

* P<0.05.

Abbreviations: y, years; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; FVC, forced volume capacity; RV, residual volume; TLC, total lung capacity; CVD, cardiovascular disease; PAD, peripheral artery disease; CRP, c-reactive protein; PAL, physical activity level.

Table 3 Multiple regression analysis of possible predictors for aortic augmentation index

	B	95% confidence interval	P-value
Nonlinear age
Age, y	2.74	0.10/5.38	0.042*
Age × age, y (squared term)	−0.02	−0.04/−0.00	0.044*
Male/female	−6.64	−9.9/−3.4	<0.001*
BMI, kg/m^2	−0.35	−0.62/−0.08	0.012*
Systolic blood pressure, mmHg	0.19	0.10/0.29	<0.001*
FEV1, %predicted	0.03	−0.05/0.10	0.474
PAL	−9.32	−16.96/−1.68	0.017*

Note:

* P<0.05.

Abbreviations: y, years; BMI, body mass index; FEV₁, forced expiratory volume in 1 second; PAL, physical activity level.

Figure 3 A scatterplot of AI and PAL adjusted for age, age × age (squared term), sex, BMI, systolic blood pressure, and FEV₁ %predicted according to the final regression model is shown.

Notes: The regression line (black line) and confidence intervals (gray bar) are marked. The figure illustrates a decrease of the AI with increasing PAL in COPD patients.
Abbreviations: AI, augmentation index; PAL, physical activity level; BMI, body mass index; FEV₁, forced expiratory volume in 1 second.