Chest
Original ResearchDevelopment of a Contemporary Bleeding Risk Model for Elderly Warfarin Recipients
Section snippets
Materials and Methods
The study design was a retrospective cohort analysis using the National Registry of Atrial Fibrillation. Briefly, the Centers for Medicare & Medicaid Services authorized the collection of data on a national, random sample of patients discharged from the hospital between April 1998 and March 1999, and between July 2000 and June 2001 with a diagnosis of AF (International Classification of Diseases, ninth revision, clinical modification, code 427.31) as part of the National Stoke Project.4, 5 We
Results
The cohort consisted of 76,177 unique observations. Reasons and counts for exclusion were made in the following order: failure to match with the Medicare denominator file; death before hospital discharge; discharged from the hospital against medical advice or discharged to an acute care hospital (n = 6,666); managed care enrollment (n = 3,215); no warfarin prescribed at the time of hospital discharge (n = 38,089); and age < 65 years (n = 1,862). There were 26,345 study subjects remaining for
Discussion
We were able to identify eight variables that were significant predictors of major bleeding events. The resulting model combining these risk factors performed well in differentiating among low-risk, moderate-risk, and high-risk groups, and likewise performed well when compared with two previous bleeding risk models. Our contemporary model improved the discrimination between subjects at risk for a bleeding event based on areas under the ROC curve and had three categories that demonstrated a
Summary
Using a nationally derived data set, we have developed a model based on contemporary practice standards for determining the risk of major bleeding events among AF patients receiving warfarin therapy. Risk scores can be computed for individuals considering the following eight separately weighted factors: age; gender; recent bleeding event; remote bleeding event; alcohol/drug abuse; diabetes; anemia; and concomitant antiplatelet therapy. Validation of this model in other study populations is
ACKNOWLEDGMENT
The authors acknowledge the assistance of the Iowa Foundation for Medical Care and the Centers for Medicare & Medicaid Services in providing the data that made this research possible.
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Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).
The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.
The conclusions presented are solely those of the authors and do not represent those of the Iowa Foundation for Medical Care or the Centers for Medicare & Medicaid Services.
The American Heart Association provided funding for this project through grant-in-aid No. 0450071Z.