Identifying Major Hemorrhage with Automated Data: Results of the Veterans Affairs Study to Improve Anticoagulation (VARIA)

Jasuja, Guneet K.; Reisman, Joel I.; Miller, Donald R.; Berlowitz, Dan R.; Ash, Arlene S.; Ozonoff, Al; Zhao, Shibei; Rose, Adam J.

doi:10.1016/j.thromres.2012.10.010

Cited by 22 publications

(30 citation statements)

References 21 publications

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“…16 Events were retained if they occurred while a patient was receiving warfarin, as described above, and fulfilled at least one of four conditions: 1) Associated with death within 30 days; 2) Associated with blood transfusion; 3) Associated with bleeding into a critical anatomic site; or 4) Cited as the main reason for a hospitalization. 16 Approximately 16 % of candidate events were retained as "major hemorrhages" by this definition, although this percentage was much higher for events likely to be severe (e.g. diverticula of colon, 46 %).…”

Section: Dependent Variable: Major Hemorrhagic Eventsmentioning

confidence: 99%

Identifying the Risks of Anticoagulation in Patients with Substance Abuse

et al. 2013

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BACKGROUND: Warfarin is effective in preventing thromboembolic events, but concerns exist regarding its use in patients with substance abuse. OBJECTIVE: Identify which patients with substance abuse who receive warfarin are at risk for poor outcomes. DESIGN: Retrospective cohort study. Diagnostic codes, lab values, and other factors were examined to identify risk of adverse outcomes. PATIENTS: Veterans AffaiRs Study to Improve Anticoagulation (VARIA) database of 103,897 patients receiving warfarin across 100 sites. MAIN MEASURES: Outcomes included percent time in therapeutic range (TTR), a measure of anticoagulation control, and major hemorrhagic events by ICD-9 codes. RESULTS: Nonusers had a higher mean TTR (62 %) than those abusing alcohol (53 %), drugs (50 %), or both (44 %, p<0.001). Among alcohol abusers, an increasing ratio of the serum hepatic transaminases aspartate aminotransferase/alanine aminotransferase (AST:ALT) correlated with inferior anticoagulation control; normal AST:ALT≤ 1.5 predicted relatively modest decline in TTR (54 %, p<0.001), while elevated ratios (AST:ALT 1.50-2.0 and > 2.0) predicted progressively poorer anticoagulation control (49 % and 44 %, p<0.001 compared to nonusers). Age-adjusted hazard ratio for major hemorrhage was 1.93 in drug and 1.37 in alcohol abuse (p<0.001 compared to nonusers), and remained significant after also controlling for anticoagulation control and other bleeding risk factors (1.69 p<0.001 and 1.22 p=0.003). Among alcohol abusers, elevated AST:ALT >2.0 corresponded to more than three times the hemorrhages (HR 3.02, p < 0.001 compared to nonusers), while a normal ratio AST:ALT ≤ 1.5 predicted a rate similar to nonusers (HR 1.19, p<0.05).CONCLUSIONS: Anticoagulation control is particularly poor in patients with substance abuse. Major hemorrhages are more common in both alcohol and drug users. Among alcohol abusers, the ratio of AST/ALT holds promise for identifying those at highest risk for adverse events.

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Section: Dependent Variable: Major Hemorrhagic Eventsmentioning

confidence: 99%

Identifying the Risks of Anticoagulation in Patients with Substance Abuse

et al. 2013

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“…Because our method of categorization differed from other studies 31 , direct comparison of studies might be difficult. While our algorithm 30 for identifying major hemorrhage had face validity, it clearly could not be as precise as a chart review. Moreover, we lacked the data power to identify new thromboembolic events, which could have been contrasted with bleeding rates to better evaluate the overall risk and benefit of warfarin therapy.…”

Section: Limitationsmentioning

confidence: 95%

“…We used data from the Veterans AffaiRs Study to Improve Anticoagulation (VARIA), 17,19 which included patients receiving warfarin therapy from the Veterans Health Administration (VHA) between October 1, 2006 and September 30,2008. To eliminate the complexities uniquely associated with therapy initiation, we only included data from the 103,897 "experienced" warfarin users, who had been on warfarin for at least 6 months (Table 1).…”

Section: Study Populationmentioning

confidence: 99%

“…30 Those patients with Medicare Part C were excluded from analyses of hemorrhage because of a high likelihood of incomplete event ascertainment, as Medicare Part C does not generate itemized bills for episodes of care. We aggregated the ICD-9 codes for hemorrhage and determined an event to be a "major hemorrhage" based one of four criteria: bleeding associated with death within 30 days, lifethreatening bleeding into a critical anatomic site, bleeding accompanied by a blood transfusion, or bleeding as the primary reason for hospital admission.…”

Section: Dependent Variable: Major Hemorrhagementioning

confidence: 99%

“…We censored patients after the first major hemorrhage event, and TTR was included in the model as a six-level categorical variable. Those patients with Medicare Part C were excluded from analysis because of incomplete event ascetainment 30 . In model 1, we analyzed the effect of any MHC on major hemorrhage, and in model 2, we analyzed the effect of individual MHCs on major hemorrhage.…”

Section: Analysesmentioning

confidence: 99%

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