Table 4. Hypercoagulability Laboratory Values in All Patients Not Receiving Warfarin Within 6 Months of Index Datea.
| Laboratory Panel and Hypercoagulable Definition | Cases (n = 19) |
Controls (n = 95) |
P Value |
|---|---|---|---|
| Antithrombin III, functional/antigen <80% | 10 (5, 50) | 12 (2, 17) | .20 |
| Anticardiolipin antibodies, IgG/IgM>15 U | 14 (5, 36) | 23 (8, 35) | >.99 |
| Factor V Leiden, heterozygous mutation | 11 (0) | 12 (1, 8) | >.99 |
| Factor VIII, >200% | 4 (3, 75) | 4 (1, 25) | .49 |
| Heparin PF4 antibody, IgG HIT antibodies detected | 8 (1, 13) | 20 (6, 30) | .63 |
| Homocysteine level, >1.62 mg/L | 6 (6, 100) | 21 (15, 71) | .28 |
| Lupus anticoagulant, screening and confirmatory positive test result | 15 (7, 50) | 18 (1, 6) | .01 |
| Protein C, functional/antigen <70% or activity <55% | 11 (5, 46) | 10 (0) | .04 |
| Protein S, functional/antigen <70% or activity <55% | 11 (4, 36) | 12 (4, 32) | >.99 |
| Prothrombin, G20210A mutation | 4 (0) | 3 (0) | >.99 |
| Any thrombophilia, ≥1 abnormal test result | 18 (13, 72) | 41 (29, 70) | >.99 |
| Combined thrombophilia, ≥2 abnormal test results | 29 (19, 66) | 22 (9, 40) | .10 |
SI conversion factor: To convert homocysteine to micromoles per liter, multiply by 7.397.
a
A subanalysis was performed comparing only cases and controls not recently exposed to warfarin. Individuals were considered to have a hypercoagulable condition if they met abnormal laboratory cutoffs listed in the first column (and were thus labeled “abnormal”). P values were obtained by Fisher exact test. Unless otherwise stated, data are given as number tested (number abnormal, percentage).