Table 2.
Univariate Association of Baseline, Treatment and Interim Exposure Characteristics with Recurrent Venous Thromboembolism among a Random Subcohort of Olmsted County, MN Residents with Incident Deep Vein Thrombosis or Pulmonary Embolism, 1988–2000.
| Characteristic | Baseline and Interim Exposure Effect (Adjusted) Hazard Ratio (95% CI) [P-value] |
|
|---|---|---|
| Baseline | Interim Exposure | |
| Male sex | 1.19 (0.95, 1.49) [0.128] | – |
| Age (years; per 10 year increase in age) | 1.06 (1.00, 1.13) [0.054] | – |
| Body mass index (BMI, kg/m2; per 10 kg/m2 increase in BMI) | 1.11 (0.96, 1.29) [0.162] | – |
| Incident PE ± DVT | 0.77 (0.60, 0.99) [0.039] | – |
| Classification of incident VTE | ||
| Active cancer | 2.40 (1.81, 3.20) | – |
| Idiopathic | 1.43 (1.10, 1.87) | – |
| Other secondary (referent) | 1.0 (referent) [F test p<.001] | – |
| Hospitalization for surgery | 0.73 (0.56, 0.96) [0.022] | – |
| Hospitalization for surgery§ | [F test p<.001] | |
| No | – | 1.0 (referent) |
| Yes, hazard ratio for in-hospital | – | 10.73 (6.48, 17.76) |
| Yes, hazard ratio for 92 days post dismissal | – | 3.15 (1.97, 5.04) |
| Hospitalization for acute medical illness | 1.15 (0.90, 1.47) [0.257] | – |
| Hospitalization for acute medical illness§ | [F test p<.001] | |
| No | – | 1.0 (referent) |
| Yes, hazard ratio for in-hospital | – | 5.82 (3.73, 9.09) |
| Yes, hazard ratio for 92 days post dismissal | – | 2.62 (1.91, 3.60) |
| Nursing home confinement | 0.74 (0.45, 1.24) [0.254] | – |
| Active cancer | 2.11 (1.62, 2.75) [<.001] | 3.11 (1.95, 4.97) [<.001] |
| Multiple active cancer types | [F test p<.001] | [F test p<.001] |
| No cancer | 1.0 (referent) | 1.0 (referent) |
| Single cancer type | 2.08 (1.59, 2.72) | 2.58 (1.97, 3.37) |
| Multiple cancer types | 3.09 (1.14, 8.41) | 5.08 (2.23, 11.54) |
| Active cancer metastases | [F test p<.001] | [F test p<.001] |
| No cancer | 1.0 (referent) | 1.0 (referent) |
| Cancer without metastases | 1.59 (1.11, 2.28) | 1.37 (0.60, 3.09) |
| Cancer with metastases | 2.94 (2.09, 4.15) | 5.73 (3.52, 9.31) |
| Active cancer stage | [F test p<.001] | [F test p<.001] |
| No cancer | 1.0 (referent) | 1.0 (referent) |
| Stage 1–3 cancer | 1.54 (1.10, 2.16) | 2.24 (1.18, 4.25) |
| Stage 4 cancer | 3.84 (2.63, 5.61) | 5.49 (3.11, 9.68) |
| Active cancer stage progression | [F test p<.001] | [F test p<.001] |
| No cancer | 1.0 (referent) | 1.0 (referent) |
| Cancer without stage progression | 2.09 (1.59, 2.74) | 2.82 (1.63, 4.89) |
| Cancer with stage progression | 2.37 (1.16, 4.86) | 5.16 (2.71, 9.80) |
| Any lifetime cancer | 1.70 (1.33, 2.16) [<.001] | 1.92 (1.53, 2.43) [<.001] |
| Trauma/fracture | 0.72 (0.49, 1.05) [0.084] | 4.24 (2.34, 7.65) [<.001] |
| Neurological disease with leg paresis | 1.11 (0.69, 1.76) [0.669] | – |
| Neurological disease with leg paresis§ | [F test p<.001] | |
| No | – | 1.0 (referent) |
| Yes, 0–92 days | – | 8.36 (3.85, 18.15) |
| Yes, >92 days | – | 0.24 (0.03, 1.70) |
| Chronic Lung Disease | 0.97 (0.71, 1.32) [0.856] | – |
| Diabetes | 1.43 (0.99, 2.06) [0.058] | – |
| Superficial vein thrombosis | 0.95 (0.71, 1.27) [0.727] | – |
| Central venous catheter | 1.28 (0.88, 1.85) [0.198] | 7.91 (5.36, 11.67) [<.001] |
| Venous Transfemoral Catheter | 0.94 (0.30, 2.93) [0.918] | 3.60 (2.01, 6.44) [<.001] |
| Pacemaker | 0.57 (0.18, 1.77) [0.330] | 2.15 (1.05, 4.37) [0.035] |
| Any infection | 1.05 (0.82, 1.34) [0.678] | 2.29 (1.78, 2.94) [<.001] |
| Respiratory infection | 1.20 (0.85, 1.68) [0.304] | 2.29 (1.61, 3.26) [<.001] |
| Urinary tract infection | 1.20 (0.81, 1.77) [0.364] | 1.93 (1.31, 2.86) [<.001] |
| Pregnancy/ Postpartum† | 0.93 (0.41, 2.10) [0.858] | - |
| Pregnancy/ Postpartum§ † | [F test p=0.135] | |
| No | – | 1.0 (referent) |
| Yes, hazard ratio for pregnancy | – | 4.20 (1.03, 17.13) |
| Yes, hazard ratio for 92 days after post-partum | – | - |
| Oral contraceptive§ | – | 1.12 (0.41, 3.06) [0.826] |
| Estrogen therapy§ | – | 0.89 (0.52, 1.53) [0.683] |
| Progestin therapy§ | – | 1.69 (0.99, 2.89) [0.053] |
| Lipid-lowering drugs | ||
| Statinठ| Р| 0.99 (0.65, 1.51) [0.978] |
| Non-statinठ| Р| 0.44 (0.19, 0.99) [0.048] |
| Unfractionated heparin therapy§ | – | 3.36 (1.95, 5.79) [<.001] |
| Intravenous heparin therapy§ | – | 2.44 (1.27, 4.70) [0.008] |
| Subcutaneous heparin therapy§ | – | 4.72 (2.21, 10.12) [<.001] |
| Therapeutic APTT within first 24 hours of heparin therapy§ | [F test p=0.45] | |
| Yes | – | 1.0 (referent) |
| No | – | 1.24 (0.87, 1.77) |
| No APTT available | – | 1.19 (0.88, 1.61) |
| Cumulative proportion of time on heparin with therapeutic APTT^§ | – | 0.95 (0.92, 0.99) [0.01] |
| Heparin status/cumulative time with therapeutic APTT§ | [F test p<.001] | |
| ▪ ≥50% of time-spent on heparin with therapeutic APTT | 2.17 (1.09, 4.31) | |
| ▪ <50% of time-spent on heparin with therapeutic APTT | 4.53 (2.54, 8.10) | |
| ▪ No APTT measured while on heparin | 1.72 (0.39, 7.56) | |
| ▪ Not on heparin | 1.0 (referent) | |
| Low molecular weight heparin therapy§ | – | 1.47 (0.64, 3.38) [0.370] |
| Warfarin therapy§ | – | 0.40 (0.28, 0.56) [<.001] |
| Cumulative proportion of time on warfarin with INR≥1.5^§ | – | 0.94 (0.89, 0.99) [0.013] |
| Warfarin status/cumulative time with INR≥1.5 | – | [F test p<.001] |
| ▪ ≥50% of time-spent on warfarin with INR≥1.5 | 0.38 (0.26, 0.55) | |
| ▪ <50% of time-spent on warfarin with INR≥1.5 | 0.69 (0.37, 1.28) | |
| ▪ No INR measured while on warfarin | 0.18 (0.04, 0.73) | |
| ▪ Not on warfarin | 1.0 (referent) | |
| Cumulative proportion of time on warfarin with INR≥2.0^§ | – | 0.98 (0.94, 1.02) [0.343] |
| Warfarin status/cumulative time with INR≥2.0 | – | [F test p<.001] |
| ▪ ≥50% of time-spent on warfarin with INR≥2.0 | 0.37 (0.25, 0.55) | |
| ▪ <50% of time-spent on warfarin with INR≥2.0 | 0.53 (0.33, 0.87) | |
| ▪ No INR measured while on warfarin | 0.18 (0.04, 0.72) | |
| ▪ Not on warfarin | 1.0 (referent) | |
| IVC filter§ | – | 1.95 (1.33, 2.84) [<.001] |
| Aspirin therapy§ | – | 0.79 (0.57, 1.10) [0.168] |
^
N=613 subjects were analyzed for each univariate model except for proportion of time on heparin (n=496) and on warfarin (n=484) variables
†
Effects for female-specific exposures were adjusted for sex.
‡
Missing interim (binary) data were imputed with a value of “yes” if the coefficient for a category assigned to unknown was similar to that of the yes level.
§
Time-dependent variable constructed for interim exposures only.