Warfarin-associated Intracerebral Hemorrhage is Increasing in Prevalence in the United States

Background: Warfarin-associated intracerebral hemorrhage (WAICH) is expected to increase in prevalence as the population ages. We sought to evaluate national trends, characteristics, and in-hospital outcomes among intracerebral hemorrhage (ICH) patients taking warfarin at baseline. Methods: We reviewed the Nationwide Inpatient Sample to identify all admissions with primary diagnosis of ICH by International Classification of Diseases, Ninth Revision code (431) from 2005 to 2008. We identified premor-bid warfarin use by the V code (V58.93) and calculated the proportion of WAICH among all ICH patients in each year. We employed univariate statistics and generalized estimating equation regression models to assess whether warfarin use independently increased the risk of in-hospital mortality after adjusting for relevant covariates. P value less than .05 was considered significant. Results: There were 52,993 patients (mean age 68.8 years; 49.7% male) coded for ICH between 2005 and 2008. The proportion with WAICH increased each year (2005, 5.8%; 2006, 6.5%; 2007, 6.9%; 2008, 7.3%; P < .001). While in-hospital mortality declined each year for non-WAICH (29.0%-25.4%, P < .001), it remained unchanged for WAICH (42.1%-40.0%, P = .346). In multivariable analysis, warfarin use (adjusted odds ratio 1.35; 95% confidence interval 1.24-1.47) remained an independent predictor of in-hospital mortality. Conclusions: WAICH is increasing in prevalence in the United States and is associated with a 35% higher mortality than non-WAICH. While mortality has declined over time for non-WAICH, mortality after WAICH is unchanged. Specific strategies to decrease the mortality of WAICH such as rapid reversal of anticoagulation are warranted.