Figures
- Fig. 1—
Median 6-min walking distance (6MWD) over 5 yrs. Baseline median (range) 6MWD was 388 m (161–600 m; n = 294). It declined at 12.5m·yr-1 (95% confidence interval 8–17 m·yr-1) for up to 5 yrs (p = 0.001). –––––: median; -------: 95% confidence intervals. Year 4: n = 163; year 5: n = 100.
- Fig. 2—
Change in 6-min walking distance (6MWD) over time as a percentage of the predicted values (% pred) as reported by a) Enright and Sherrill 18 (2.1%·yr-1 (95% confidence interval (CI) 1.6–2.7%·yr-1); p<0.001); and b) Troosters et al. 19 (1.6%·yr-1 (95% CI 1.1–2.1%·yr-1); p<0.001). –––––: median; -------: 95% CI. Baseline, years 1–3: n = 294; year 4: n = 163; year 5: n = 100.
- Fig. 3—
The 6-min walking distance (6MWD) declines significantly in patients with a forced expiratory volume in one second (FEV1) <50% predicted (-------; 15.3 m·yr-1 (95% confidence interval (CI) 9.1–21.4 m·yr-1); p = 0.002). –––––: FEV1 >50% pred, years 0–3: n = 85; year 4: n = 44; year 5: n = 25). FEV1 <50% pred, years 0–3: n = 209; year 4: n = 119; year 5: n = 75).
- Fig. 4—
The decline in 6-min walk distance (○) was greater in patients with more severe airflow obstruction, as determined by Global initiative for Chronic Obstructive Lung Disease and American Thoracic Society/European Respiratory Society staging criteria. In contrast forced expiratory volume in one second (FEV1; •) changed less in those patients with more severe airflow limitation. Δ: change. Stage II: n = 81; stage III: n = 136; stage IV: n = 73.
Tables
- Table 1—
Baseline characteristics of the patients
Subjects n 294 Sex M/F 285/9 Age yrs 66 (51–79) Current smokers % 18 BMI kg·m-2 27 (19–36) 6MWD m 388 (160–600) FEV1 L 1.13 (0.64–2.22) FEV1 % pred 39 (20–70) GOLD and ATS/ERS staging Stage I 4 (1) Stage II 81 (28) Stage III 136 (46) Stage IV 73 (25) IC/TLC 0.28 (0.16–0.42) Charlson index 4 (1–7) Data are presented as n, median (5th–95th percentile) or n (%), unless otherwise stated. M: male; F: female; BMI: body mass index; 6MWD: 6-min walking distance; FEV1: forced expiratory volume in one second; % pred: % predicted; GOLD: Global Initiative for Chronic Obstructive Lung Disease; ATS: American Thoracic Society; ERS: European Respiratory Society; IC: inspiratory capacity; TLC: total lung capacity.
- Table 2—
Characteristics of the cohort according to country
USA Spain p-value Subjects 200 84 Sex M/F 193/7 83/1 0.443 Age yrs 66 (51–79) 67 (47–76) 0.461 BMI kg·m-2 27 (18–37) 27 (19–36) 0.658 6MWD m 350 (146–503) 463 (336–635) <0.001 FEV1 L 1.20 (0.6–2.1) 1.15 (0.6–2.3) 0.946 FEV1 % pred 37 (19–67) 43 (21–75) 0.014 IC/TLC 0.29 (0.14–0.42) 0.28 (0.13–0.44) 0.385 Charlson index 4 (2–8) 2 (1–6) <0.001 Data are presented as n or median (5th–95th percentile). M: male; F: female; BMI: body mass index; 6MWD: 6-min walking distance; FEV1: forced expiratory volume in one second; % pred: % predicted; IC: inspiratory capacity; TLC: total lung capacity.
