Chronic kidney disease and atrial fibrillation (AF) commonly coexist, and data 
suggest that renal patients have AF rates in excess of double that encountered 
in the general population. These patients are at increased risk of stroke, 
regardless of the presence or absence of AF. Furthermore, a lower GFR causes 
increased thromboembolic risk in patients with AF - independent of other risk 
factors. The dilemma facing clinicians treating this cohort of patients is that 
renal insufficiency confers both a thromboembolic and a bleeding risk. Renal 
disease also commonly coexists with other risk factors for stroke and bleeding 
such as hypertension and advanced age. Furthermore, bleeding risk tracks stroke 
risk and many risk factors are common to both thromboembolism and haemorrhage. 
Patients with severe renal impairment are also actively excluded from the 
majority of trials for stroke prevention in AF, including those trials which 
informed the development of stroke risk factor scoring schemes. Therefore, 
patients with renal disease and AF present a unique management challenge. The 
available data suggests that the benefit from warfarin in terms of stroke 
reduction is not as clear as in the general population, and there is an 
increased risk of bleeding complications and even ectopic vascular 
calcification. Thus, it is problematic to extrapolate the benefits of warfarin 
in the general population to a subgroup that has been actively excluded from 
clinical trials. The new oral anticoagulants have relatively little data in 
patients with severe renal impairment, and all have an element of renal 
excretion. There is a need for large randomised control trials in patients with 
renal insufficiency and on haemodialysis to provide a bank of high-quality 
scientific data on which clinicians can base their management decisions. Until 
then, we must adopt a pragmatic approach which involves careful consideration of 
the relative risk of stroke and bleeding in each individual patient.