| Trip [41] | Chandra [44] | ||||||
| DLCO <45% | DLCO ≥45% | p-value | DLCO <43% | DLCO 43–64% | DLCO >64% | p-value | |
| Subjects n | 48 | 118 | 135 | 135 | 138 | ||
| Age years | 67# | 46# | <0.001 | 55¶ | 47¶ | 45¶ | <0.0001 |
| Males | 50 | 19 | 0.01 | 22 | 21 | 25 | 0.74 |
| Former smoker | 58 | 30 | 0.07 | ||||
| Current smoker | 19 | 18 | 0.77 | ||||
| 6MWD m | 275+ | 390+ | 0.03 | ||||
| Metabolic equivalents | 2.6 | 3.7 | 4.2 | <0.0001 | |||
| NYHA WHO FC I/II | 21 | 35 | 0.05§ | 9 | 25 | 26 | <0.0001ƒ |
| NYHA WHO FC III/IV | 79 | 65 | 91 | 75 | 74 | ||
| Anti-nuclear antibodies | 38 | 20 | 0.06 | 79 | 55 | 32 | <0.0001 |
| RAP mmHg | 7.3+ | 8.1+ | ns | 11 | 11 | 11 | 0.83 |
| mPAP mmHg | 47+ | 52+ | ns | 49 | 54 | 54 | 0.02 |
| CI mL·min−1·m−2 | 2.3+ | 2.5+ | ns | 2 | 2 | 2 | 0.78 |
| PVR Wood Units | ns | 11 | 13 | 13 | 0.03 | ||
| TPVR dyn·s·cm−5 | 1000+ | 1004+ | |||||
| HR (95% CI) | 3.8 (2.2–6.6)## | <0.001 | 2.7 (1.9–3.9)## | <0.001 | |||
| 2.4 (1.1–5.0)¶¶ | 0.025 | ||||||
Data are presented as %, unless otherwise stated. 6MWD: 6-min walking distance; NYHA: New York Heart Association; WHO: World Health Organization; FC: functional class; RAP: right atrial pressure; mPAP: mean pulmonary artery pressure; CI: cardiac index; PVR: pulmonary vascular resistance; TPVR: total PVR; HR: hazard ratio; ns: nonsignificant. #: median age at diagnosis; ¶: mean age at study entry; +: approximate value based on data from [42]; §: FC I/II versus III/IV; ƒ: across all groups; ##: univariate analysis; ¶¶: multivariate analysis.