Systematic review of long term anticoagulation or antiplatelet treatment in patients with non-rheumatic atrial fibrillation

Objective To examine the benefits and risks of long term anticoagulation (w arfarin) compared with antiplatelet treatment (aspirin/indoprofen) in patie nts with non-rheumatic atrial fibrillation. Methods Meta-analysis of randomised controlled trials from Cochrane library , Medline, Embase, Cinhal, and Sigle fr am 1966 to December 1999. Odds rati os (95% confidence intervals) calculated to estimate treatment effects. Outcome measures Fatal and non-fatal cardiovascular events, reductions of w hich were classified as benefits. Fatal and major non-fatal bleeding events classified as risks. Results No trials were found from before 1989. There were five randomised c ontrolled trials published between 1989-99. There were no significant diffe rences in mortality between the two treatment options (fixed effects model: odd ratio 0.14 (95% confidence interval 0.39 to 1.40) for stroke deaths; 0 .86 (0.63 to 1.17) for vascular deaths). There was a borderline significant difference in non-fatal stroke in favour of anticoagulation (0.68 (0.46 to 0.99)); and 0.15 (0.50 to 1.13) after exclusion of one trial with weak met hodological design. A random effects model showed no significant difference in combined fatal and non-fatal events (odds ratio 0.79 (0.61 to 1.02)), T here were more major bleeding events among patients on anticoagulation than on antiplatelet treatment (odds ratio 1.45 (0.93 to 2.27)). One trial was stopped prematurely after a significant difference in favour of anticoagula tion was observed, The only trial to show a significant difference in effec t (favouring anticoagulation) was methodologically weaker in design than th e others. Conclusions The heterogeneity between the trials and the limited data resul t in considerable uncertainty about the value of long term anticoagulation compared with antiplatelet treatment The risks of bleeding and the higher c ost of anticoagulation make it an even less convincing treatment option.