Treating elderly AF patients with anticoagulation improves survival, more so than antiplatelets

Wändell PE, Carlsson AC, Sundquist J, et al.
Age Ageing. 2014 Oct 16. pii: afu153. [Epub ahead of print]

Background

The annual risk of stroke in patients with atrial fibrillation (AF) strongly increases with age, from 1.5% in those between ages 50 and 59, to 23.5% in those aged 80-89 [1]. Thus, stroke prevention in the elderly is very important. Antithrombotic therapy recommendations in AF rely on stroke risk prediction by CHADS₂  or preferably by CHA₂DS₂VASc [2]. Since in CHA₂DS₂VASc, age >75 years already scores 2 points, all those AF patients should at least be considered for anticoagulation therapy if high risk of bleeding is absent.
Laplace regression analysis is a new analysis method to calculate life years gained or lost due to a certain type of pharmacotherapy [3]. This study set out to analyse years of survival in AF patients of 75 years and older prescribed antiplatelets and anticoagulants. In addition, it aimed to establish the effects of other cardiovascular drugs that are commonly prescribed in these patients. To this end, individual-level patient data were used from individuals diagnosed with AF when aged >75 years in one of 75 primary health-care centres in Sweden (mean follow-up time: 3.4 years, SD: 2.1, total 22735 person-years at risk).

Main results

• Laplace regression modelling showed that significant longer survival were associated with anticoagulants vs. no treatment (survival increase: 1.95 years, 95%CI: 1.43-2.48) and with anticoagulants vs. antiplatelets (survival increase: 0.78, 95%CI: 0.38-1.18) in men and women combined in sex-adjusted models.
• Similar survival increases were seen for thiazides vs. no treatment (0.81, 95%CI: 0.43-1.18) and calcium channel blockers vs. no treatment (0.83, 95%CI: 0.47-1.18).
• A significant interaction by sex was seen for RAS blockade and ACE inhibitors vs. no treatment, and further analysis revealed that only women had a longer survival with these agents (0.61, 95%CI: 0.05-1.18 and 0.66, 95%CI: 0.05-1.27 respectively). Men had shorter survival with aldosterone antagonists vs. no treatment (-0.96, 95%CI: -1.32 to -0.60).
• No differences in mortality were seen according to the different CHADS₂ and CHA₂DS₂VASc categories, and no significant differences were seen between men and women.

Conclusion

These analyses show that treatment of AF patients aged >75 years with anticoagulants is associated with increased survival, as compared to no treatment or treatment with antiplatelets. These results thus confirm the superiority of anticoagulants over antiplatelets in reducing mortality in these patients. This was true for both men and women. Differences between the sexes were seen for treatment with aldosterone antagonists, RAS blockers and ACE inhibitors. Most studied pharmaceutical groups were associated with decreased mortality when prescribed to AF patients, but not all.

Find this article on Pubmed

References

1. Kannel WB, Wolf PA, Benjamin EJ, Levy D. Prevalence, incidence, prognosis, and predisposing conditions for atrial fibrillation: population-based estimates. Am J Cardiol 1998; 82(8A): 2N–9N.
2. Larsen TB, Lip GY, Skjoth F, et al. Added predictive ability of the CHA2DS2VASc risk score for stroke and death in patients with atrial fibrillation: the prospective Danish Diet, Cancer, and Health cohort
study. Circ Cardiovasc Qual Outcomes 2012; 5: 335–42.
3. Orsini N, Wolk A, Bottai M. Evaluating percentiles of survival. Epidemiology 2012; 23: 770–1.