Monday, October 24, 2011
Grand Ballroom AB (Hyatt Regency Chicago)
Poster Board # 17
(ESP) Applied Health Economics, Services, and Policy Research
Candidate for the Lee B. Lusted Student Prize Competition
Anna K. Donovan, M.D.1, Margaret V. Ragni, M.D., M.P.H.1 and Kenneth J. Smith, MD, MS2, (1)University of Pittsburgh School of Medicine, Pittsburgh, PA, (2)University of Pittsburgh, Pittsburgh, PA
Purpose:
Anticoagulation guidelines suggest anticoagulation (AC) duration after unprovoked venous thromboembolism (VTE) should be determined by an individual risk assessment, balancing bleeding and VTE recurrence risks. Few models consider these risks objectively
. The RIETE database (Ruiz-Gimenez, Thromb Haemost 2008;100:26-31) incorporates six risk factors for anticoagulation bleeding into a model that categorizes bleeding with AC into low-, medium-, or high-risk categories. Methods: We constructed a Markov model to compare lifetime anticoagulation vs. shorter durations in patients with unprovoked VTE. Risks of major, minor, and fatal bleeding with and without AC, VTE risk, morbidity, mortality, and quality of life utilities were obtained from the literature. We used decision analysis techniques to assess the influence of RIETE variables, including 1) age >75 years, 2) cancer, 3) creatinine >1.2, and 4) major bleeding on AC duration. Results:
In a two-way sensitivity analysis, we compared the effects of varying bleeding and VTE risk, for four specific RIETE bleeding risk factors (Figure). Despite the increased risk of bleeding associated with age, cancer, anemia, renal disease, and major bleed, incorporating these variables did not necessarily have the expected effect on AC strategy. All scenarios were close to the line of indifference between AC strategies. Cancer was in the range where long-term AC is not favored, in contrast to current guidelines (CHEST 2008). Conversely, major bleeding and renal failure fell where long-term AC is not favored, in line with clinical practice. Conclusion:
While cancer, renal disease, age, and major bleeding contribute to bleeding risk on AC, these risks alone may not predict optimal AC duration when associated VTE risks are also considered. Since all factors fell close to the line of indifference between strategies, it appears that better methods to assess and calculate individual patient risk are needed to optimize patient-specific AC decisions.
