Table 1. Patient characteristics by anti-PF4/heparin antibody status.
Characteristics of the study population, including prior anticoagulant exposure, mostly expressed as the number and percentage of the total with the listed characteristic. Positive antibody status is defined as an OD > 0.4 either pre-event or at the follow-up visit 30 days after surgery.
| Demographics | Negative (n=363) |
Positive (n=627) |
P value |
|---|---|---|---|
| Age (mean+/− SD) | 62.5 (11.7) | 60.7 (11.8) | 0.06 |
| Gender (% female) | 25.1 | 28.6 | 0.24 |
| Race | |||
| African American | 11.0 | 13.6 | 0.25 |
| Native American | 3.9 | 4.9 | 0.43 |
| White | 85.4 | 81.5 | 0.11 |
| Hispanic ethnicity | 1.4 | 1.4 | 0.94 |
| Body mass index (kg/m2) | 28.8 (6.2) | 29.4 (5.8) | 0.15 |
| Co-morbidities/risk factors | |||
| Diabetes | 35.2 | 36.1 | 0.79 |
| Hypertension | 73.7 | 71.9 | 0.55 |
| History of cancer | 19.3 | 15.8 | 0.16 |
| In remission | 16.5 | 14.8 | 0.48 |
| Undergoing therapy | 2.8 | 1.0 | 0.03 |
| Smoker | |||
| Current | 11.6 | 11.2 | 0.85 |
| Former | 55.1 | 53.6 | 0.64 |
| Hypercholesterolemia | 72 | 69 | 0.33 |
| End stage renal disease (kidney failure) | 11.1 | 9.9 | 0.57 |
| Prior hemodialysis graft thrombosis | 33.3 | 0 | 0.94 |
| Hormone replacement or oral contraceptive* | 9.9 | 3.9 | 0.05 |
| Miscarriage | 25.3 | 22.7 | 0.64 |
| Previous MI | 42.0 | 36.1 | 0.07 |
| Previous stroke | 9.9 | 9.1 | 0.67 |
| Previous HIT diagnosis | 0 | 0.5 | 0.19 |
| Enoxaparin or dalteparin | 8.0 | 7.7 | 0.85 |
| Intravenous heparin | 41.3 | 38.3 | 0.34 |
| Any prior venous thrombosis | 5.0 | 3.5 | 0.26 |
| Any prior arterial thrombosis | 47.1 | 39.2 | 0.02 |
| Current warfarin use | 2.5 | 2.2 | 0.80 |
| Preoperative | |||
| Prior cardiac surgery | 6.1 | 6.1 | 0.99 |
| Prior cardiac catheterization | 96.4 | 92.4 | 0.01 |
| Prophylactic anticoagulant use | 21.6 | 19.0 | 0.32 |
Abbreviations used include: SD, Standard deviation; MI, Myocardial infarction; HIT, Heparin induced thrombocytopenia; LMWH, Low molecular weight heparin; UFH, Unfractionated heparin; OD, Optical density.