Abstract Number: OC 06.1
Meeting: ISTH 2021 Congress
Theme: Venous Thromboembolism » Cancer Associated Thrombosis
Background: Direct oral anticoagulants (DOACs) have comparable efficacy with low-molecular-weight heparin for the treatment of cancer-associated venous thromboembolism (VTE). Whether there is a mortality benefit of DOACs compared with warfarin in the management of VTE in cancer is not established.
Aims: Evaluate overall survival outcomes of DOACs versus warfarin in the treatment of cancer-associated VTE.
Methods: We performed a retrospective cohort analysis using the Surveillance, Epidemiology and End Results (SEER)-Medicare linked database from 2012 through 2016. Eligible patients were individuals with primary gastric, colorectal, pancreatic, lung, ovarian, or brain cancer who were diagnosed with venous thromboembolism and prescribed DOACs or warfarin within 30 days of VTE diagnosis. Patients were matched 1:2 DOAC:warfarin using exact matching for cancer stage and propensity score matching for age, cancer site, cancer stage, and time interval from cancer to VTE diagnosis. The primary outcome was overall survival. Cox proportional-hazards regression was performed to estimate hazard ratios and 95% confidence intervals (95% CI).
Results: A total of 4,044 patients were included (1,348 in DOACs group and 2,696 in warfarin group). Demographic characteristics are presented in Table 1. Within the DOACs group, 1,188 (88%) received rivaroxaban and 160 (12%) received apixaban. With a median follow-up of 40 months, DOACs were associated with a statistically significantly shorter overall survival compared to warfarin (median overall survival, 9.9 months [95%CI: 8.4 to 11.2] versus 12.0 months [95%CI: 10.9 to 13.5]; hazard ratio, 1.18; 95% CI: 1.10 to 1.27; p<0.001) (Figure 1). The observed trend in survival differences were consistent across subgroups of cancer sites, cancer stages, and type of VTE.
|
Total N = 4,044 |
DOACs N = 1,348 |
Warfarin N = 2,696 |
|
|---|---|---|---|
| Age at VTE diagnosis, median (IQR) | 75 (70 – 81) | 75 (70 – 81) | 75 (70 – 81) |
| Female sex, n (%) | 2,284 (56) | 761 (56) | 1,523 (56) |
| Median Elixhauser Comorbidity Index Score, median (IQR) | 5 (4 – 7) | 5 (4 – 7) | 5 (4 – 7) |
|
Primary cancer site, n (%) Gastric Colorectal Pancreatic Lung Ovarian Brain |
172 (4) 1,376 (34) 532 (13) 1,624 (40) 199 (5) 141 (3) |
59 (4) 446 (33) 207 (15) 558 (41) 31 (2) 47 (3) |
113 (4) 930 (34) 325 (12) 1,066 (40) 168 (6) 94 (3) |
|
Cancer stage at diagnosis, n (%) 1-2 3 4 N/A Unknown |
1,170 (29) 1,116 (28) 1,371 (34) 189 (5) 198 (5) |
390 (29) 372 (28) 457 (34) 63 (5) 66 (5) |
780 (29) 744 (28) 914 (34) 126 (5) 132 (5) |
| Received systemic anti-cancer therapy within 3 months of VTE diagnosis, n (%) | 1,522 (38) | 559 (41) | 963 (36) |
|
Type of index VTE, n (%) Deep-vein thrombosis Pulmonary embolism |
2,349 (58) 1,695 (42) |
788 (58) 560 (42) |
1,561 (58) 1,135 (42) |
| Months from cancer diagnosis to index VTE, median (IQR) | 4.8 (1.1 – 20.6) | 4.6 (1.1 – 19.5) | 4.9 (1.1-21.0) |
Demographic and clinical characteristics of study cohort after propensity-score Matching.
Kaplan-Meier curves of overall survival in DOACs-treated patients (solid line) versus warfarin-treated patients (dashed line) with cancer-associated venous thromboembolism.
Conclusions: In this retrospective analysis of a large registry database, warfarin was associated with improved overall survival compared to DOACs for treatment of cancer-associated VTE.
To cite this abstract in AMA style:
Chiasakul T, M Khan A, Redd R, Patell R, P McCarthy E, Neuberg D, I Zwicker J. Improved Overall Survival with Warfarin Compared with Direct Oral Anticoagulants in Cancer-associated Venous Thromboembolism: A SEER-medicare Analysis [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 1). https://abstracts.isth.org/abstract/improved-overall-survival-with-warfarin-compared-with-direct-oral-anticoagulants-in-cancer-associated-venous-thromboembolism-a-seer-medicare-analysis/. Accessed September 16, 2021.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/improved-overall-survival-with-warfarin-compared-with-direct-oral-anticoagulants-in-cancer-associated-venous-thromboembolism-a-seer-medicare-analysis/