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Introduction Stroke prevention among patients with nonvalvular atrial fibrillation (NVAF) requires careful assessment of both the risk of stroke and bleeding. Hypothesis We hypothesized that in a real-world managed care population of patients with NVAF, bleeding incidence increases with CHADS2 stroke risk. Methods Administrative claims data were used for this retrospective study. Adults with healthcare claims related to AF (ICD-9-CM 427.31) between Jan 2005 and Jun 2009 but no evidence of valvular disease were included. Patients were followed until the earliest of death, disenrollment from the health plan, or 30 Jun 2010. Patients were categorized based on CHADS2 scores of 0, 1, 2, or ≥3, with higher scores indicating more risk factors. A bleeding event was considered major if it was associated with any of the following: inpatient care, blood transfusion, decreased hemoglobin or hematocrit, death, physician guided medical or surgical treatment, or intracranial bleed. Serious non-major events were those involving vascular injury or critical site bleeding and were associated with outpatient hospital care or an emergency department visit. Minor bleeds were those associated with noncritical anatomical sites and an emergency department, outpatient hospital, or office visit. Results The mean (SD) age of the study sample (N=48,260) was 67±13 years and 62% of the patients were male. Mean follow-up duration was 802±540 days (median 673 days). Mean (SD) baseline CHADS2 score was 1.48±1.15. Event rates for each bleeding category increased with increasing CHADS2 scores (Table). Conclusions Patients with NVAF in a real-world managed care setting who had high stroke risk also had a high rate of bleeding events, including major events. Patients at high risk for stroke might require more careful selection of anticoagulation therapy to avoid bleeding events.

Introduction Warfarin discontinuation among real world nonvalvular atrial fibrillation (NVAF) patients is common. Hypothesis We hypothesized that in a managed care population, warfarin discontinuation is associated with increased stroke risk. Methods Patients who initiated warfarin therapy between Jan 2005 and Jun 2009 and had a healthcare claim related to AF within 30 days prior to the first warfarin claim, but no evidence of valvular disease, were included. Warfarin discontinuation was defined as a supply gap of >60 days without evidence of International Normalized Ratio (INR) measurements. Follow-up was divided into periods of warfarin treatment and discontinuation. Stroke events were identified based on claims for inpatient stays with a primary diagnosis for stroke or transient ischemic attack (TIA). Cox proportional hazards models were constructed to assess the relationship between warfarin discontinuation and incident stroke while adjusting for baseline demographics, stroke and bleeding risk, and comorbidities, as well as time-dependent antiplatelet use, stroke, and bleeding events in the prior warfarin treatment period. Results The mean (SD) age of the study sample (N=16,253) was 67±12 years; 64.8% was male. Mean CHADS2 score was 1.84±1.30; mean HAS-BLED score was 2.00±1.18. Half (51.4%) of patients discontinued warfarin therapy at least once and the overall sample had a mean of 1.87 warfarin treatment periods during a mean of 668 days follow-up. Approximately 1186 patients (7%) had a stroke or TIA at any site of service during follow-up. Risk of stroke significantly increased during warfarin discontinuation periods compared with therapy periods (HR 1.60; 95%CI 1.35-1.90; P Conclusions In the real world, over half of patients on anticoagulation therapy had treatment gaps or permanently discontinued therapy. These usage patterns, as well as prior bleeding, were associated with increased stroke risk.

Introduction Bleeding among patients with nonvalvular atrial fibrillation (NVAF) may prevent subsequent anticoagulation, and consequent inadequate stroke prophylaxis could extend the economic impact of bleeding beyond the acute event. Hypothesis We hypothesized that costs for NVAF patients rise acutely following a major bleed and stay elevated through extended follow-up compared with costs for NVAF patients without a major bleed. Methods Adults with healthcare claims related to AF between Jan 2005 and Jun 2009 but no evidence of valvular disease were included. Follow-up lasted until the earliest of death, disenrollment from the health plan, or 30 Jun 2010. A bleeding event was considered major if it was associated with any of the following: inpatient care, blood transfusion, decreased hemoglobin or hematocrit, death, physician guided medical or surgical treatment, or intracranial bleed. Among patients with major bleeding events, average daily costs were calculated in the pre-bleed (from the index date until the event) and post-bleed (from the end of the event until the end of follow-up) periods, and during the event. Among patients without major bleeding events, the average daily cost during the entire follow-up period was calculated. Results Among 48,260 patients with NVAF (mean age 67±13 years; 62% male), 7908 (16%) had a major bleeding event during a mean (SD) follow-up of 802±540 days (median 673 days). Major bleeding events lasted a mean of 15±25 days and averaged $16,830 per event. Among patients who experienced a major event, average costs per patient increased from approximately $50 per day in the pre-bleed period to $63 per day in the post-bleed period, a difference of approximately $13 per day. Daily costs for NVAF patients who did not experience a major bleeding event averaged approximately $36 per day; thus, average daily costs for patients who had a major bleed were greater in both the pre- and post-bleed periods (by $14 per day and $27 per day, respectively) than for patients who did not have a major event. Cost differences persisted 2 years following incident major bleeding events. Conclusions Major bleeding events among NVAF patients are associated with substantial healthcare costs, both directly related to the event and in the post-event period.