Warfarin Use and the Risk for Stroke and Bleeding in Patients With Atrial Fibrillation Undergoing Dialysis – Mitesh Shah et al. Circulation. 2014;129:1196-1203.
A retrospective cohort study
Population based cohort of patients > 65 years who were admitted in Canada – Quebec and Ontario with a primary or secondary diagnosis of atrial fibrillation. Used ICD-9/10 codes to determine diagnosis and complications such as bleeding and stroke complications. Drug prescriptions were identified by database in Canada where patients > 65 have prescription benefit. Warfarin use was identified by a filled prescription within 30-days of AF diagnosis
626 dialysis patients and 204,210 nondialysis patients. Did not separate by stages of CKD, but rather HD or non-HD. Dialysis patients were younger, male, CHF, HTN, DM, CAD, and bleeding history.
Dialysis vs Non-Dialysis: CHADS2 >/= 2: 72% versus 55% (indication for anti-coagulation); HAS-BLED >/=3: 85% versus 25%. Similar rates of warfarin prescription (46% vs 51%)
In non-dialysis patients, warfarin users had a lower incidence of stroke (2.19 vs 2.51/100 person-years)
In dialysis patients, stroke incidence was similar for warfarin and non-warfarin users: 3.37 versus 2.91/100 person-years.
After adjusting for confounders – warfarin use had a HR of 1.14 in diaylsis patients. While in non-dialysis patients had a HR 0.87 with warfarin use.
After adjusting for confounders, warfarin use, was associated with a 44% higher risk for bleeding event in dialysis patients and 19% higher risk in nondialysis patients.