Figures
- FIGURE 1
Kaplan–Meier survival curve examining long-term oxygen therapy (LTOT) initiation at baseline. p<0.001 by log-rank test.
- FIGURE 2
Kaplan–Meier survival curve comparing subjects with a fall in forced vital capacity (FVC) >10% with those without. p=0.024 by log-rank test.
- FIGURE 3
Comparison of average forced vital capacity (FVC) change following a fall in FVC >10%. Data are presented as median (interquartile range). p<0.001 by Mann–Whitney test.
- FIGURE 4
Change in forced vital capacity (FVC) by interval to last follow-up.
Tables
- TABLE 1
Baseline demographic and physiological variables
Male 137 (82) Current or ex-smoker 116 (69.5) Definite UIP on CT 131 (78.4) Pulmonary hypertension 31 (18.6) Exertional desaturation 98 (68.1) LTOT initiation 31 (18.6) Pirfenidone use at any time 45 (26.9) Overall mortality 67 (40.1) 6-month mortality 15 (9.0) 12-month mortality 23 (13.8) 24-month mortality# 49 (48.5) Age years 73.5 (71.9–75.0) BMI kg·m−2 26.7 (25.9–27.6) FVC % pred 83.0 (79.6–86.5) FEV1 % pred 84.5 (80.7–88.3) DLCO % pred 52.8 (49.2–56.4) FEV1/FVC ratio % 81.5 (80.2–82.9) 6-min walking distance m 283.8 (264.9–302.8) 6-min walking distance % pred 60.6 (56.7–64.5) Borg on exertion 2.7 (2.4–2.9) Lowest SaO2 on exertion 87.5 (86.3–88.6) Data are presented as n (%) or mean (95% CI). UIP: usual interstitial pneumonia; CT: computed tomography; LTOT: long-term oxygen therapy; BMI: body mass index; FVC: forced vital capacity; FEV1: forced expiratory volume in 1 s; DLCO: diffusing capacity of the lung for carbon monoxide; SaO2: arterial oxygen saturation. #: n=101.
- TABLE 2
Best-performing models on multivariable Cox proportional hazards analysis
Hazard ratio (95% CI) Significance Model significance Baseline variables# Male 2.278 (1.126–4.608) 0.022 <0.001 LTOT initiation 2.050 (1.156–3.636) 0.014 FVC 1.020 (0.999–1.041) 0.058 DLCO 0.985 (0.970–1.000) 0.044 Inability to perform DLCO assessment 2.915 (1.380–6.158) 0.005 12-month follow-up¶ DLCO 0.953 (0.931–0.974) <0.001 <0.001 Change in DLCO 0.984 (0.972–0.997) 0.014 Male 1.933 (0.886–4.219) 0.098 Data are presented as mean (95% CI), unless otherwise stated. LTOT: long-term oxygen therapy; FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide. #: n=167; ¶: n=126.
- TABLE 3
Multidimensional indices: baseline values and univariable Cox regression hazard ratios
Mean (95% CI) Hazard ratio (95% CI) p-value CPI 41.42 (38.64–44.21) 1.064 (1.040–1.089) <0.001 DSP 249 (232–266) 0.996 (0.993–0.998) 0.001 GAP I 21 (12.7) Reference GAP II 86 (51.8) 1.501 (0.847–2.661) 0.164 GAP III 59 (35.5) 5.466 (2.604–11.474) <0.001 du Bois score# 18.3 (16.4–20.2) 1.039 (1.011–1.067) 0.006 Data are presented as n (%), unless otherwise stated. CPI: Composite Physiological Index; DSP: distance–saturation product; GAP: Gender, Age, Physiology score. #: n=126.
- TABLE 4
Comparison of multidimensional indices with individual variables by received operating characteristic (ROC) analysis at 12 and 24 months
12-month ROC c-statistic p-value for comparison with FVC 24-month ROC c-statistic p-value for comparison with FVC Age 0.694 0.213 0.639 0.942 FVC 0.564 Ref. 0.645 Ref. DLCO 0.705 0.040 0.770 0.041 Walking distance 0.702 0.135 0.591 0.491 Lowest SaO2 0.669 0.212 0.638 0.922 CPI 0.657 0.037 0.761 0.013 GAP 0.636 0.115 0.722 0.091 DSP 0.729 0.073 0.623 0.785 FVC: forced vital capacity; DLCO: diffusing capacity of the lung for carbon monoxide; SaO2: arterial oxygen saturation; CPI: Composite Physiological Index; GAP: Gender, Age, Physiology score; DSP: distance–saturation product; Ref.: reference.
Supplementary Material
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Supplementary data 00096-2016_Supplementary_data
