Blood pressure response to exposure to moderate altitude in patients with COPD

Figures & data

Table 1 Patient characteristics

Characteristics	COPD patients at baseline (n=37)
Age (years)	64.3 (6.3)
Male, n (%)	26 (79)
BMI (kg/m^2)	26.3 (4.8)
FEV1 (L)	1.7 (0.7)
FEV1 (% predicted)	60 (17)
RV/TLC	47.9 (8.3)
RV/TLC (%)	122 (21)
TLCO(Hb) (mmol/min/kPa)	5.7 (2.3)
TLCO(Hb) (%)	64 (20)
paO2 (kPa)	8.9 (1.2)
paCO2 (kPa)	5.5 (0.6)
SpO2 (%)	93.5 (1.8)
SABA, n (%)	10 (27)
SAMA, n (%)	2 (5)
LABA, n (%)	30 (81)
LAMA, n (%)	29 (78)
ICS, n (%)	23 (62)
Hypertension, n (%)	23 (62)
Beta blocker, n (%)	7 (19)
Angiotensin converting enzyme inhibitor or angiotensin receptor blocker, n (%)	18 (49)
Other antihypertensive drugs (calcium antagonist or diuretic), n (%)	16 (43)
Cardiovascular disease, n (%)	4 (11)
Diabetes mellitus type 2, n (%)	1 (3)

Note: Data are given as mean (SD) unless otherwise mentioned.

Abbreviations: BMI, body-mass-index; ICS, inhaled corticosteroid; LABA, inhaled long-acting beta-agonist; LAMA, inhaled long-acting muscarinic antagonist; paCO₂, arterial partial pressure of carbon dioxide; paO₂, arterial partial pressure of oxygen; RV, residual vol; SABA, inhaled short-acting beta-agonist; SAMA, inhaled short-acting muscarinic antagonist; SpO₂, finger pulse oximeter-based oxygen saturation; TLC, total lung capacity; TL_CO(Hb), carbon monoxide transfer factor adjusted for hemoglobin.

Figure 1 Study flowchart.

Table 2 ANOVA for repeated measurements

Outcome	490 m, n=37	2,590 m day 1, n=37	2,590 m day 2, n=37
Mean SBP (mmHg)	122.4 (21.5)	133.2 (21.6)*	131.1 (16.5)*
Mean DBP (mmHg)	65.4 (13.1)	70.4 (9.1)*	69.0 (9.5)
CV SBP (%)	6.6 (1.7)	7.4 (1.7)	8.3 (2.0)*,^
CV DBP (%)	6.9 (2.3)	7.6 (2.5)	8.7 (2.4)*,^
BRS (msec/mmHg)	7.8 (9.1)	4.8 (3.2)*	4.9 (2.7)*
Heart rate (bpm)	68.5 (8.3)	75.2 (10.0)*	73.2 (7.9)*,^

Notes: Data are presented as mean (SD).

* P<0.05 vs 490 m.

^ P<0.05 vs 2,590 m day 1.

Abbreviations: BRS, baroreflex sensitivity; CV, coefficient of variation.

Figure 2 ANOVA of repeated measurements.

Notes: Comparison of (A) SBP, (B) DBP, (C) blood pressure variability, and (D) spontaneous baroreflex sensitivity (BRS) between low altitude and day 1 and day 2 at moderate altitude. Vertical bars denote 95% CIs. *P<0.05 vs 490 m. ^{^}P<0.05 vs 2,590 m day 1.