This is “one of the first studies to show a relationship between use of lipid-lowering therapy and improved long term outcomes for hard end points in patients with atrial fibrillation,” senior author Dr. Sony Jacob from Wayne State University, Detroit, Michigan told Reuters Health by e-mail.
In the AFFIRM study, investigators randomized 4060 patients with atrial fibrillation to treatment that targeted either heart rhythm or heart rate. At randomization, 913 of the study subjects were on lipid-lowering therapy.
During an average follow-up of 3.5 years, 666 patients died (124 in the lipid-lowering group and 542 in the other group). There were 331 cardiovascular deaths (64 and 267 in the two groups, respectively).
In an April 30 online article in the American Journal of Cardiology, Dr. Jacobs and colleagues report that on multivariate analysis, lipid-lowering therapy was associated with lower all-cause mortality (hazard ratio, 0.77; p = 0.01), cardiovascular mortality (HR, 0.71; p = 0.02), ischemic stroke (HR, 0.56; p = 0.01), and the combined end point of death, ventricular tachycardia or fibrillation, cardiac arrest, ischemic stroke, major bleeding, systemic embolism, pulmonary embolism, and myocardial infarction (HR, 0.81; p = 0.01).
The effect, Dr. Jacob noted, “is clearly over and beyond the lipid-lowering effect and whether it is due to other known pleiotropic effect like anti-inflammatory, antioxidant or anti-thrombogenesis, or unknown factors, which stabilizes the interplay of structural, electrophysiological and molecular substrate of atrium is yet to be studied.”
Dr. Jacob and colleagues note that theirs was a retrospective analysis, and they did not have details on lipid-lowering therapy (statin vs fibrates, type of statin, and dosages used), inflammatory markers, and lipid profiles. They also note that subjects on lipid-lowering therapy differed significantly from non-users. Patients on lipid-lowering therapy were also taking significantly more cardioprotective medications such as beta-blockers, aspirin, and angiotensin converting enzyme inhibitors.
On the other hand, the lipid-lowering users, versus non-users, were generally sicker, with a higher prevalence of diabetes, hypertension and coronary artery disease. Lipid-lowering therapy was therefore used more often in patients who would otherwise be expected to be at greater risk of premature mortality.
“At present, data only supports statin use in atrial fibrillation patients who require it for other reasons and obviously if not contraindicated,” Dr. Jacob told Reuters Health. “However, this trend very likely will change in the future as more evidence from both basic science and clinical research evolves.”
Dr. Jacob continued, “I believe, given the atrial fibrillation burden and variable outcomes with other treatment modalities, (that) atrial structural stabilization using pharmacological means such as statins (or other newer pharmacological agents) in the early stage of the disease process will improve the outcome.”
Am J Cardiol 2010.