Table 4. Univariate analysis of clinical, lung functional and echocardiographic variables according to the 6-minute walking distance (m).
| Variables | Coefficient β (95% CI) | p-value |
|---|---|---|
| E/A ratio | 88.2 (20.4 to 156.0) | 0.012*† |
| PaO2, mmHg | 1.9 (-0.4 to 4.2) | 0.102† |
| DLCO quartile 4th | -63.2 (-110.1 to -16.3) | 0.009*† |
| Smoking, pack-years | -0.9 (-1.7 to -0.1) | 0.024*† |
| Age, years | -2.5 (-5.2 to 0.2) | 0.071† |
| TAPSE, mm | 5.0 (-0.2 to 10.2) | 0.060† |
| FEV1, % pred | 1.0 (-2.4 to 4.4) | 0.557 |
| IC/TLC ratio | 3.7 (-336.2 to 343.6) | 0.983 |
| Diabetes | -24.2 (-77.2 to 28.7) | 0.364 |
| Pulmonary hypertension | 10.3 (-37.1 to 57.6) | 0.666 |
| BMI, kg/m2 | -0.13 (-4.2 to 3.9) | 0.948 |
| Use of ACEIs / ARBs | 10.7 (-33.7 to 55.2) | 0.632 |
Definition of abbreviations: CI = confidence interval; E/A ratio = ratio of early (E) to late (A) mitral flow peak velocities; DLCO = diffusing capacity for carbon monoxide; TAPSE = tricuspid annular plane systolic excursion; FEV1 = forced expiratory volume in 1 second IC/TLC = inspiratory-to-total lung capacity ratio; BMI = body mass index; ACEI = angiotensin-converting enzyme inhibitor; ARA = angiotensin receptor antagonist; * A p value <0.05 was considered to be statistically significant; †p<0.2 was considered for the multivariate analysis.