Characteristics of the sleep study cohort at baseline and 1 year.
No AHRF (n = 94)
AHRF (n = 66)
value
Age (years)
65.4 (63.4–67.5)
67.6 (65.4–69.8)
0.16
Sex (male)
50 (53.2)
34 (51.5)
0.83
Weight (kg)
71.0 (60.1–84.4)
76.8 (71.2–82.3)
0.47
BMI
26.6 (23.2–31.7)
29.1 (27.1–31.1)
0.31
pH
7.4 (7.4–7.4)
7.4 (7.4–7.4)
0.04
PaO2
9.2 (8.9–9.7)
8.5 (8.1–8.8)
<0.01
PaCO2
5.0 (4.5–5.6)
5.7 (5.5–5.9)
<0.01
HCO3-
25.2 (24.0–26.5)
27.4 (26.2–28.7)
<0.01
BE
0.6 (−1.1-2.5)
2.35 (1.2–4.9)
<0.01
Hypercapnia
7 (7.4)
13 (19.7)
0.02
CAT
23.5 (21.8–25.2)
22.7 (20.5–25.0)
0.5
Epworth sleep score
9.0 (5.0–14.0)
8.00 (4.0–12.0)
0.2
Bronchiectasis (% of those with CT)
13/68 (19.1)
5/40 (12.5)
0.37
Emphysema
56/68 (82.35)
30/40 (75)
0.59
LTOT
10/94 (10.6)
10/66 (15.2)
0.40
Pack years
45.0 (30.0–60.0)
48.5 (38.0–64.3)
0.12
FEV1
1.4 (0.9–1.8)
0.9 (0.7–1.5)
<0.01
FEV1 % predicted
56.5 (52.2–60.9)
43.77 (39.55–47.99)
<0.01
FVC
2.7 (2.6–2.9)
2.3 (2.1–2.5)
<0.01
FVC % predicted
86.5 (72.0–100.0)
76.1 (71.2–81.0)
<0.01
FEV1/FVC
0.5 (0.5–0.6)
0.5 (0.4–0.5)
0.02
OSA on sleep study
14 (14.9)
29 (43.9)
<0.01
AHI
2.4 (0.6–4.6)
3.7 (0.5–8.8)
0.09
ODI
5.6 (3.3–10.1)
7.5 (4.5–14.1)
0.08
Mean oxygen sats during sleep study
90.4 (87.7–92.5)
89.6 (85.6–92.6)
0.26
Time under 90%
12.0 (1.6–52.3)
23.1 (3.5–96.1)
0.04
Death at 12 months
5/94 (5.3)
10/66 (15.2)
0.35
Follow-up PaCO2
4.9 (4.5–5.6)
4.9 (4.5–5.4)
0.66
Data are shown as mean (SE) or median (IQR) for quantitative measures, and n (%) for binary outcomes, which are further denoted by italic text. CAT = COPD assessment test, LTOT = long-term oxygen therapy, AHI = apnoea hyponoea index, and ODI = oxygen desaturation index.
