Abstract 12186: The Association of Warfarin Control With Pulmonary Embolism Mortality: The CVRN VTE Study
Background: There are few data about how warfarin control is associated with venous thromboembolism outcomes. We describe 1-year mortality after pulmonary embolism (PE) at various therapeutic levels of warfarin.
METHODS: We searched electronic databases from four integrated healthcare delivery systems from January 1, 2004 to December 31, 2010 for all adult patients with a primary diagnosis code of PE during an emergency department or inpatient visit, and who were newly prescribed warfarin within 7 days of discharge. Clinical, utilization, and mortality data were obtained from automated clinical databases. Using linear interpolation, serial measurements of the international normalized ratio (INR) were used to calculate the proportion of time in a therapeutic INR range of 2 - 3 (TTR). We used Cox regression analysis to test the association between TTR and 1-year mortality.
Results: We identified 5600 patients who were prescribed warfarin for a diagnosis of acute PE. The median duration of warfarin treatment was 9.4 months and 544 (9.7%) of patients had died by one year. The mean TTR on warfarin (excluding the first 4 weeks of warfarin initiation) was 49.1%. Mortality was significantly associated with warfarin control (p≤0.001, see Figure). After adjusting for age, sex, comorbid factors, and duration of warfarin treatment, lower TTRs were associated with higher mortality: compared to patients with TTR ≥70%, the adjusted hazard ratio of death was 3.8 [95%CI: 2.4-6.0] with TTR 40-49%, and 8.0 [95%CI: 5.4-12.1] with TTR ≤ 40%.
Conclusions: The one-year mortality in warfarin-treated patients with PE was nearly 10%. The overall mean TTR was less than 50%. Mortality was higher among patients with lower proportions of time in a therapeutic INR range on warfarin.
- © 2013 by American Heart Association, Inc.