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Table 1 Comparisons of baseline characteristics between patients with and without an acute exacerbation

From: Risk factors for an acute exacerbation of idiopathic pulmonary fibrosis

  Non-AE   AE   P Value a
(N = 41) (N = 24)
Age, median (IQR), y 69.0 (62.0 to 73.0) 68.0 (62.0 to 73.5) 0.995
Sex, No. (%)
 Men 31 (75.6) 20 (83.3) 1.000
 Women 10 (24.4) 4 (16.7)  
Smoking, No. (%)
 S 7 (17.1) 3 (12.5) 1.000
 Ex 25 (61.0) 17 (70.8)  
 N 9 (22.0) 4 (16.7)  
Smoking index, pack-years 35.8 (1.0 to 52.3) 31.3 (15.0 to 50.0) 0.940
Cardiovascular diseases, No. (%)
 Yes 10 (24.4) 8 (33.3) 1.000
 No 31 (75.6) 16 (66.7)  
Atopic diseases, No. (%)
 Yes 3 (7.3) 1 (4.2) 1.000
 No 38 (92.7) 23 (95.8)  
Baseline pulmonary function
 VC, median (IQR), % predicted 81.0 (64.1 to 95.0) 69.2 (59.5 to 83.0) 0.074
 FVC, median (IQR), % predicted 80.4 (59.0 to 93.9) 70.5 (59.9 to 82.1) 0.055
 TLC, median (IQR), % predicted 75.9 (63.0 to 90.0) 66.1 (54.0 to 77.0) 0.020
 DLCO, median (IQR), % predicted 58.0 (46.1 to 72.5) 46.2 (41.0 to 72.3) 0.276
 KCO, median (IQR), % predicted 69.5 (60.8 to 85.0) 73.0 (57.7 to 78.0) 0.866
GAP stage, No. (%)
 I 25 (69.4) 10 (45.5) 1.000
 II 9 (25.0) 12 (54.5)  
 III 2 (5.6) 0 (0.0)  
CPI 37.3 (22.2 to 47.6) 47.7 (30.5 to 54.9) 0.190
Respiratory parameters b
 PaO2, median (IQR), mm Hg 80.7 (75.3 to 91.0) 81.0 (75.2 to 94.5) 0.810
 A-a DO2, median (IQR), mm Hg 17.5 (3.8 to 26.2) 17.2 (4.1 to 25.2) 0.889
Hematologic data
 WBC, median (IQR),/mm3 6700 (5800 to 8100) 7350 (5750 to 9300) 0.442
 Neutrophils, median (IQR), % 62.8 (57.0 to 69.4) 63.9 (58.0 to 69.0) 0.897
 Eosinophils, median (IQR), % 3.0 (2.0 to 4.7) 2.9 (1.8 to 4.4) 0.545
Serum markers
 CRP, median (IQR), mg/dL 0.31 (0.06 to 0.69) 0.29 (0.13 to 0.64) 0.688
 LDH, median (IQR), U/L 235 (187.0 to 255.0) 247 (223.5 to 296.0) 0.082
 KL-6, median (IQR), U/mL 912 (595.0 to 1802.0) 1258 (744.5 to 2006.0) 0.246
 SP-D, median (IQR), ng/mL 203 (131.0 to 342.0) 269 (178.6 to 343.0) 0.285
BAL fluid findings
 Total cell count, median (IQR), ×105/mL 2.50 (1.40 to 3.67) 3.21 (2.22 to 3.97) 0.099
 Macrophages, median (IQR), % 80.2 (62.5 to 88.9) 76.6 (67.3 to 84.8) 0.492
 Lymphocytes, median (IQR), % 6.8 (3.9 to 11.4) 11.6 (3.2 to 17.1) 0.649
 Neutrophils, median (IQR), % 6.7 (2.9 to 13.3) 7.0 (3.2 to 10.5) 0.807
 Eosinophils, median (IQR), % 3.3 (1.2 to 5.4) 4.6 (2.1 to 7.0) 0.259
 CD4/8 ratio, median (IQR) 1.90 (0.86 to 3.70) 1.10 (0.60 to 1.90) 0.065
Treatment after the diagnosis
Steroid, No. (%)
 yes 7 (17.1) 8 (33.3) 1.000
 No 34 (82.9) 16 (66.7)  
Immunosuppressive agent c, No. (%)
 Yes 3 (7.3) 6 (25.0) 1.000
 No 38 (92.7) 18 (75.0)  
Steroid with immunosuppressive agent, No. (%)
 Yes 3 (7.3) 5 (20.8) 1.000
 No 38 (92.7) 19 (79.2)  
Pirfenidone, No. (%)
 Yes 8 (19.5) 6 (25.0) 1.000
 No 33 (80.5) 18 (75.0)  
NAC, No. (%)
 Yes 8 (19.5) 5 (20.8) 1.000
 No 33 (80.5) 19 (79.2)  
  1. Abbreviations: AE acute exacerbation, N number of patients, IQR interquartile range, S/Ex/N current smoker/ex-smoker/nonsmoker, VC vital capacity, FVC forced vital capacity, TLC total lung capacity, DLCO diffusing capacity for carbon monoxide, KCO carbon monoxide transfer coefficient, GAP gender-age-physiology, CPI composite physiologic index, P/F ratio PaO2/fraction of inspired oxygen ratio, A-a DO 2 alveolar-arterial difference in oxygen, WBC white blood cell count, CRP C-reactive protein, LDH lactate dehydrogenase, KL-6 Krebs von den Lungen-6, SP-D surfactant protein-D, BAL bronchoalveolar lavage, CD4/8 ratio CD4/CD8 lymphocyte subset ratio, NAC inhaled N-acetylcysteine
  2. Data are presented as the median (interquartile range)
  3. aWilcoxon’s rank-sum test was performed for continuous variables, and Fisher’s exact test was performed for categorical variables
  4. bOne patient in the Non-AE group required oxygen (1 L/min O2 via a nasal cannula) at the time of sample collection. All other results were obtained at room air
  5. cImmunosuppressive agents included cyclosporine (N = 7) and cyclophosphamide (N = 2)
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