Clinical characteristics of the complete cohort*
| WHO group I | WHO group II | WHO group III | WHO group IV | WHO group V | P† | |
| Number of patients (n=132) | 49 | 53 | 13 | 13 | 4 | – |
| Demographics | ||||||
| Age, years | 56 (42–65) | 72 (60–76) | 68 (56–73) | 55 (47–61) | 57 (44–69) | <0.01 |
| Male gender | 11 (22%) | 12 (23%) | 7 (54%) | 5 (38%) | 3 (75%) | 0.03 |
| Body mass index, kg/m2 | 30 (26–33) | 33 (27–39) | 27 (26–32) | 31 (29–31) | 26 (24–29) | 0.04 |
| Chronic medical conditions | ||||||
| Connective tissue disease | 28 (57%) | 5 (9%) | 4 (31%) | 1 (8%) | 0 (0%) | <0.01 |
| COPD | 6 (12%) | 3 (6%) | 5 (38%) | 0 (0%) | 1 (25%) | 0.01 |
| Interstitial lung disease | 11 (22%) | 3 (5%) | 8 (62%) | 0 (0%) | 0 (0%) | <0.01 |
| Right heart catheterisation | ||||||
| MPAP, mm Hg | 35 (29–45) | 42 (33–52) | 31 (27–32) | 38 (36–46) | 26 (23–37) | 0.02 |
| PAOP, mm Hg | 11 (9–14) | 21 (17–27) | 11 (10–12) | 13 (11–14) | 13 (11–14) | <0.01 |
| PVR, wood units | 3.3 (2.4–8.1) | 3.2 (2.6–6.0) | 4.1 (3.2–5.1) | 4.3 (3.5–11.2) | 2.6 (1.9–5.5) | 0.30 |
| Sleep study | ||||||
| Home sleep study | 12 (24%) | 23 (43%) | 2 (15%) | 8 (62%) | 4 (100%) | <0.01 |
| Time with SpO2<90%, % | 7.6 (0.1–40.7) | 16.5 (2.6–45.5) | 2.3 (0.3–20.9) | 40.3 (23.9–97.7) | 4.6 (3.1–6.9) | 0.02 |
| AHI-REI ≥5 | 20 (41%) | 40 (75%) | 5 (38%) | 9 (69%) | 3 (75%) | 0.03 |
| 5≤AHI REI < 15 | 12 (24%) | 14 (26%) | 5 (38%) | 4 (31%) | 3 (75%) | 0.06 |
| 15≤AHI REI < 30 | 4 (8%) | 13 (25%) | 0 (0%) | 3 (23%) | 0 (0%) | 0.07 |
| AHI-REI≥30 | 4 (8%) | 13 (25%) | 0 (0%) | 2 (15%) | 0 (0%) | – |
| AHI-REI, events per hour | 2.8 (0.9–9.5) | 12.0 (6.1–29.2) | 3.7 (2.1–8.2) | 10.0 (2.2–19.4) | 6.4 (2.6–10.1) | <0.01 |
| Obstructive apnoeas | 0 (0–5) | 6 (0–33) | 2 (0–8) | 5 (0–13) | – | 0.20 |
| Central apnoeas | 0 (0–1) | 0 (0–3) | 1 (0–9) | 4 (0–5) | – | 0.16 |
| Mixed apnoeas | 0 (0–1) | 0 (0–2) | 0 (0–0) | 0 (0–1) | – | 0.81 |
| Hypopneas | 7 (3–26) | 63 (36–100) | 3 (1–34) | 64 (51–162) | – | <0.01 |
*Data are summarised as median (IQR) for continuous variables and N (%) for categorical variables.
†P values are calculated using the Kruskal-Wallis test for continuous variables and the Χ2 test for categorical variables. P<0.05 was considered statistically significant. P-values <0.05 are indicated in boldface.
AHI, apnoea-hypopnoea index; COPD, chronic obsrructive pulmonary disease; MPAP, mean pulmonary artery pressure; PAOP, pulmonary artery occlusion pressure; PVR, pulmonary vascular resistance; REI, respiratory event index.