Table 6

Cox regression modelling of individual clotting defects and survival in the IPF cohort

Clotting defectNumber of deaths (n=56)Person-yearsCrude mortality rate (95% CI) per 1000 person-yearsHR* (95% CI)HR† (95% CI)
No clotting defects453.574.7 (28.1 to 199.1)1.001.00
Prothrombotic state‡52206.9251.3 (199.5 to 329.8)3.38 (1.22 to 9.41) p=0.0063.45 (1.21 to 9.82) p=0.007
Prothrombin gene mutation310.6282.3 (91.0 to 875.18)3.88 (0.84 to 17.85)4.12 (0.87 to 19.48)
Factor V Leiden mutation25.2383.5 (95.9 to 1533.3)4.77 (0.85 to 26.85)4.83 (0.83 to 28.14)
MTHFR homozygous gene mutation723.1302.5 (144.2 to 634.5)3.85 (1.11 to 13.34) 3.95 (1.10 to 14.15)
Antithrombin III deficiency§36.6453.0 (146.1 to 1404.5)5.59 (1.22 to 25.59)5.73 (1.22 to 26.81)
Elevated factor VIII >165 IU/dL41155.6263.53 (194.0 to 357.9)3.52 (1.25 to 9.88)3.56 (1.24 to 10.20)
Free protein S <65 IU/dL1227.7433.1 (246.0 to 762.6)5.56 (1.77 to 17.44)6.10 (1.88 to 19.78)
Protein C <64 IU/dL617.8337.2 (151.5 to 750.6)3.92 (1.09 to 14.07)4.37 (1.18 to 16.15)
Clot lysis time >240 min46202.7227.0 (170.0 to 303.0)3.63 (1.30 to 10.16)3.67 (1.28 to 10.53)
D-dimer >180 IU/dL35135.7257.8 (185.1 to 359.1)3.77 (1.33 to 10.71)3.69 (1.27 to 10.76)
Lupus anticoagulant16.9144.9 (20.4 to 1028.9)1.64 (0.18 to 14.93)1.41 (0.14 to 14.03)
Anticardiolipin IgG antibodies23.8530.9 (132.8 to 2122.7)6.23 (1.11 to 35.09)6.55 (1.06 to 40.32)
1 clotting defect present¶30143.3209.4 (146.4 to 299.4)2.91 (1.02 to 8.30)2.95 (1.01 to 8.63)
2 or more clotting defects present¶2263.6345.9 (227.7 to 525.3)4.35 (1.49 to 12.73)
p for trend=0.003
4.76 (1.56 to 14.50)
p for trend=0.003
  • Bold type denotes the main findings of the study.

  • *HRs adjusted for age category and sex.

  • †HRs adjusted for age category, sex, smoking habit and hsCRP category.

  • ‡Prothrombotic state is a composite binary outcome where at least a single clotting defect was detected on laboratory testing.

  • §Antithrombin deficiency was defined as levels that lay below 2SDs from the mean value of the general population controls.

  • ¶Sum of the number of individual clotting defects detected on laboratory testing.

  • hsCRP, highly sensitive C reactive protein; IPF, idiopathic pulmonary fibrosis; MTHFR, methylenetetrahydrofolate reductase.