Implementing hospital guidelines improves warfarin use in non-valvular atrial fibrillation: a before-after study

Background: The use of oral anticoagulant therapy ( OAT) to prevent non-valvular atrial fibrillation (NVAF) related-strokes is often sub-optimal. We aimed to evaluate whether implementing guidelines on antithrombotic therapy ( AT) by a multifaceted strategy may improve appropriateness of its prescription in NVAF-patients discharged from a large tertiary-care hospital. Methods: A survey was conducted on all consecutive NVAF patients discharged before ( 1(st) January-30(th) June 2000, n = 313) and after ( 1(st) January - 30(th) June 2004, n = 388) guideline development and implementation. Results: When strongly recommended, OAT use increased from 56.6% ( 60/ 106 in 2000) to 81.9% ( 86/ 105 in 2004), with an absolute difference of +25.3% ( 95% CI: 15% 35%). In patients for whom the choice OAT/ acetylsalicylic acid should be individualised, those discharged without any AT were 33.7% ( 34/ 101) in 2000 and 16.9% ( 21/ 124) in 2004 (- 16.7%; 95% CI: - 26.2% - 7.2%). In a logistic regression model, OAT prescription in 2004 was increased by 2.11 times ( 95% CI: 1.47 3.04), after accounting for stroke risk, presence of contraindications ( OR = 0.18; 0.13 0.27), older age ( OR = 0.30; 0.21 0.45), prophylaxis at admission ( OR = 3.03; 2.08 4.43). OAT was positively associated with the stroke risk in the 2004 sample only. Conclusion: The guideline implementation has substantially improved the appropriateness of OAT at discharge, through a better evaluation at patient's individual level of the benefit-to-risk ratio.