03986nas a2200529   4500000000100000008004100001653001100042653000900053653001900062653001100081653001600092653002200108653001500130653002600145653001400171653003100185653001900216653003100235653001500266653001900281653003300300653001200333653001600345653002400361653002100385653001300406100002100419700001200440700002500452700001900477700001800496700001400514700001800528700002100546700001700567700001800584700001700602700001800619700001900637700002200656700003500678245018100713300001200894490000700906520252900913022001403442       2017                            d10aHumans10aAged10aCohort Studies10aStroke10aComorbidity10aAged, 80 and over10aCreatinine10aRetrospective Studies10aMortality10aGlomerular Filtration Rate10aCause of Death10aIschemic Attack, Transient10aHemorrhage10aAnticoagulants10aRenal Insufficiency, Chronic10aAlberta10aAlbuminuria10aAtrial Fibrillation10aPropensity Score10aWarfarin1 aTonelli Marcello1 aJun Min1 aWinkelmayer Wolfgang1 aPerkovic Vlado1 aJames Matthew1 aMa Zhihai1 aZhang Jianguo1 aMcAlister Finlay1 aManns Braden1 aRavani Pietro1 aQuinn Robert1 aWiebe Natasha1 aWilton Stephen1 aHemmelgarn Brenda1 aAlberta Kidney Disease Network00aWarfarin Initiation, Atrial Fibrillation, and Kidney Function: Comparative Effectiveness and Safety of Warfarin in Older Adults With Newly Diagnosed Atrial Fibrillation.  a734-7430 v693 a<p>
<b>BACKGROUND: </b>The effectiveness and safety of warfarin use among patients with atrial fibrillation (AF) and reduced kidney function are uncertain.
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<b>STUDY DESIGN: </b>Community-based retrospective cohort study (May 1, 2003, to March 31, 2012) using province-wide laboratory and administrative data in Alberta, Canada.
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<b>SETTING &amp; PARTICIPANTS: </b>14,892 adults 66 years or older with new AF and a measurement of kidney function. Long-term dialysis patients or kidney transplant recipients were excluded.
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<b>PREDICTOR: </b>Propensity scores were used to construct a matched-pairs cohort of patients with AF who did and did not have a warfarin prescription within a 60-day period surrounding their AF diagnosis.
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<b>OUTCOMES: </b>Within 1 year of initiating warfarin therapy (or the matched date for nonusers): (1) the composite of all-cause death, ischemic stroke, or transient ischemic attack (also assessed as separate end points) and (2) first hospitalization or emergency department visit for a major bleeding episode defined as an intracranial, upper or lower gastrointestinal, or other bleeding.
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<b>MEASUREMENTS: </b>Baseline glomerular filtration rate (GFR) was estimated using the CKD-EPI creatinine equation. Patients were matched within estimated GFR (eGFR) categories:&nbsp;≥90, 60 to 89, 45 to 59, 30 to 44, and&nbsp;&lt;30mL/min/1.73m(2). Information for baseline characteristics (sociodemographics, comorbid conditions, and prescription drug use) was obtained.
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<b>RESULTS: </b>Across eGFR categories, warfarin therapy initiation was associated with lower risk for the composite outcome compared to nonuse (adjusted HRs [95% CI] for eGFR categories&nbsp;≥ 90, 60-89, 45-59, 30-44, and&nbsp;&lt;30mL/min/1.73m(2): 0.59 [0.35-1.01], 0.61 [0.54-0.70], 0.55 [0.47-0.65], 0.54 [0.44-0.67], and 0.64 [0.47-0.87] mL/min/1.73m(2), respectively). Compared to nonuse, warfarin therapy was not associated with higher risk for major bleeding except for those with eGFRs of 60 to 89mL/min/1.73m(2) (HR, 1.36; 95% CI, 1.13-1.64).
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<b>LIMITATIONS: </b>Selection bias.
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<b>CONCLUSIONS: </b>Among older adults with AF, warfarin therapy initiation was associated with a significantly lower 1-year risk for the composite outcome across all strata of kidney function. The risk for major bleeding associated with warfarin use was increased only among those with eGFRs of 60 to 89mL/min/1.73m(2).
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  a1523-6838