Association between individual clotting defects and IPF
| Clotting defect | Prevalence in cases (n=211) (%) | Prevalence in controls (n=256) (%) | OR* (95% CI) | OR† (95% CI) |
|---|---|---|---|---|
| No clotting defects | 41 (19.4) | 137 (53.5) | 1.00 | 1.00 |
| Prothrombotic state‡ | 170 (80.6) | 119 (46.5) | 4.38 (2.85 to 6.74), p<0.0001 | 4.78 (2.93 to 7.80), p<0.0001 |
| Prothrombin gene mutation | 10 (4.7) | 6 (2.3) | 1.74 (0.61 to 5.02) | 1.73 (0.52 to 5.72) |
| Factor V Leiden mutation | 5 (2.4) | 11 (4.3) | 0.49 (0.16 to 1.49) | 0.44 (0.13 to 1.43) |
| MTHFR homozygous gene mutation | 21 (10.0) | 24 (9.4) | 1.08 (0.55 to 2.11) | 1.07 (0.51 to 2.28) |
| Antithrombin III deficiency§ | 7 (3.3) | 2 (0.8) | 5.54 (1.06 to 29.02) | 5.20 (0.92 to 29.37) |
| Elevated factor VIII levels >165 IU/dL | 129 (61.1) | 45 (17.6) | 7.21 (4.65 to 11.18), p<0.0001 | 7.02 (4.29 to 11.59), p<0.0001 |
| Free protein S <65 IU/dL | 23 (10.9) | 12 (4.7) | 2.12 (1.00 to 4.48) | 2.06 (0.90 to 4.74) |
| Protein C <64 IU/dL | 15 (7.1) | 6 (2.3) | 2.90 (1.07 to 7.90) | 2.66 (0.89 to 8.00) |
| Clot lysis time >240 min | 163 (77.3) | 170 (66.4) | 1.87 (1.21 to 2.88) | 1.60 (0.98 to 2.83) |
| D-dimer >180 IU/dL | 115 (54.5) | 100 (39.1) | 1.72 (1.16 to 2.54) | 1.69 (1.09 to 2.62) |
| Lupus anticoagulant | 4 (1.9) | 2 (0.8) | 2.90 (0.48 to 17.35) | 5.38 (0.75 to 38.33) |
| Anticardiolipin IgG antibodies | 4 (1.9) | 0 (0) | 0 | 0 |
Bold type denotes the main findings of the study.
*ORs are adjusted for age category and sex.
†ORs are adjusted for age category, sex, smoking habit and hsCRP category.
‡Prothrombotic state is a composite binary variable where at least a single clotting defect was detected on laboratory testing.
§Antithrombin deficiency was defined as levels below 2SD from the mean value of the general population controls.
hsCRP, highly sensitive C reactive protein; IPF, idiopathic pulmonary fibrosis; MTHFR, methylenetetrahydrofolate reductase.