Thrombosis risk in acquired risk situations: The Leiden Thrombophilia Study.*
| Risk Factor . | Patients (n = 474) . | Controls (n = 474) . | OR . | CI 95 . |
|---|---|---|---|---|
| *Details of the Leiden Thrombophilia Study have been described in detail elsewhere.64 Briefly, it is a population based case-control study; cases were unselected consecutive patients aged 18-70 with a first objectively diagnosed deep-vein thrombosis and controls were acquaintances of cases or spouses of (other) cases. Controls were matched for age and sex. Subjects with active malignancies were excluded. | ||||
| Time window for surgery, hospitalization (without surgery), and immobilization (not in the hospital, >13 days) was 1 year preceding the index date (i.e., date of thrombosis diagnosis in patients, similar date in controls); for puerperium it was delivery 30 days or less prior to the index date; and for pregnancy and oral contraceptives it was at the index date. Data on pregnancy, puerperium, and oral contraceptive use refer to women of childbearing age; hence the denominator is not all 474 patients or controls. | ||||
| Abbreviations: OR, odds ratio; CI, confidence interval. | ||||
| n(%) | n(%) | |||
| Surgery | 85 (18) | 17 (3.6) | 5.9 | 3.4–10.1 |
| Hospitalization | 59 (12) | 6 (1.3) | 11.1 | 4.7–25.9 |
| Immobilization | 17 (3.6) | 2 (0.4) | 8.9 | 2.0–38.2 |
| Pregnancy | 8 (5.0) | 2 (1.3) | 4.2 | 0.9–19.9 |
| Puerperium | 13 (8.2) | 1 (0.6) | 14.1 | 1.8–109 |
| Oral contraceptives | 109 (70) | 65 (38) | 3.8 | 2.4–6.0 |
| Risk Factor . | Patients (n = 474) . | Controls (n = 474) . | OR . | CI 95 . |
|---|---|---|---|---|
| *Details of the Leiden Thrombophilia Study have been described in detail elsewhere.64 Briefly, it is a population based case-control study; cases were unselected consecutive patients aged 18-70 with a first objectively diagnosed deep-vein thrombosis and controls were acquaintances of cases or spouses of (other) cases. Controls were matched for age and sex. Subjects with active malignancies were excluded. | ||||
| Time window for surgery, hospitalization (without surgery), and immobilization (not in the hospital, >13 days) was 1 year preceding the index date (i.e., date of thrombosis diagnosis in patients, similar date in controls); for puerperium it was delivery 30 days or less prior to the index date; and for pregnancy and oral contraceptives it was at the index date. Data on pregnancy, puerperium, and oral contraceptive use refer to women of childbearing age; hence the denominator is not all 474 patients or controls. | ||||
| Abbreviations: OR, odds ratio; CI, confidence interval. | ||||
| n(%) | n(%) | |||
| Surgery | 85 (18) | 17 (3.6) | 5.9 | 3.4–10.1 |
| Hospitalization | 59 (12) | 6 (1.3) | 11.1 | 4.7–25.9 |
| Immobilization | 17 (3.6) | 2 (0.4) | 8.9 | 2.0–38.2 |
| Pregnancy | 8 (5.0) | 2 (1.3) | 4.2 | 0.9–19.9 |
| Puerperium | 13 (8.2) | 1 (0.6) | 14.1 | 1.8–109 |
| Oral contraceptives | 109 (70) | 65 (38) | 3.8 | 2.4–6.0 |