Nov 4, 2004

Hamilton, ON - An economic analysis of the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study has shown that rhythm control is consistently more expensive than rate control, approximately $5000 more per patient, leaving investigators to suggest that on the basis of cost, rate control is the preferred alternative in patients with atrial fibrillation (AF).[1]

"This analysis of AFFIRM shows that, over a wide range of assumptions, rhythm control was both more costly and less effective than rate control," report Dr Deborah A Marshall (McMaster University, Hamilton, ON) and colleagues in the November 1, 2004 issue of the Annals of Internal Medicine. "In general, for patients with atrial fibrillation similar to those enrolled in AFFIRM, rate control is a cost-effective approach to the management of atrial fibrillation when compared with the maintenance of sinus rhythm."

Originally presented at the 2002 American College of Cardiology meeting and subsequently published in the New England Journal of Medicine—both reported by heartwire—the AFFIRM study showed that a strategy of rate control was at least as good as rhythm control for patients with persistent AF.[2] In patients with AF and risk factors for stroke, the strategy of restoring and maintaining sinus rhythm had no clear advantage over the strategy of controlling the ventricular rate and allowing atrial fibrillation to persist.

The economic analysis was designed to compare the costs and effects of the two management strategies among patients enrolled in AFFIRM from the perspective of a third-party payer. The study compared randomized data on the efficacy and resource use of the two strategies over a mean of 3.5 years. The analysis considered costs of all hospitalizations, cardiac procedures, cardioversion, short-stay and emergency-department visits, and medications used to treat AF. For each measure of resource used, three unit costs were used in separate analyses: a base case for the most likely scenario, a low estimate, and a high estimate.

Patients in the rate-control group used fewer resources, with the most notable differences observed in the number of hospital days, the number of cardiovascular hospital days, all types of cardioversion, and short-stay and emergency visits. The incremental cost of rhythm control compared with rate control was $5077 more per person using a most-likely scenario analysis.

"Regardless of which scenario was used, rhythm control was dominated by rate control (rhythm control was both less effective and more costly than rate control)," write Marshall and colleagues.

The authors report that the generalizability of the economic results is limited to patients similar to those enrolled in AFFIRM, those being patients with AF who were at least 65 years of age or who had other risk factors for stroke or death. Although the results can be applied to many patients, they probably cannot be generalized to younger patients without risk factors for stroke or death, they add.

An editorial by Drs Tristram Bahnson and Augustus Grant (Duke University Medical Center, Durham, NC) points out that the findings are robust and that this is one of the first reports from the AFFIRM data to show an advantage of one treatment strategy, namely rate control.[3]

"The higher cost for rhythm control confirms our intuition that this strategy often requires hospitalization for antiarrhythmic drug loading, cardioversion, or acute rate control for recurrent rapid atrial fibrillation," write the editorialists. They point out, however, that the AFFIRM results cannot be generalized to young patients with lone AF, a group that makes up 15% of the population.

A Perspective accompanying the AFFIRM economic analysis by Drs Peter Zimetbaum and Mark Josephson (Beth Israel Deaconess Medical Center, Boston, MA) also makes the same point, stressing that the equivalent status of rate control and anticoagulation compared with antiarrhythmic drug use cannot be generalized to all AF patients.[4] For patients with symptoms despite rate control, those with difficulty achieving rate control, and those who are not candidates for anticoagulation, as well as for the prevention of atrial remodeling, the maintenance of sinus rhythm is reasonable. They point out that in the AFFIRM study, rate control was not effective in 15% of patients, and these patients had to be crossed over to the rhythm-control strategy.

Although the maintenance of sinus rhythm does not confer a mortality advantage, does not reduce the thromboembolic risk, and now is shown to cost more per patient, "these medications remain important therapeutic options for certain patients," Zimetbaum and Josephson add.

According to Bahnson and Grant, the AFFIRM results in aggregate give important guidance about treating patients with AF, given the study qualifications. Because it is safe and less costly, rate control is the preferred first treatment option, together with anticoagulation, in elderly patients at high risk for stroke. When patients continue to have considerable symptoms despite a best attempt at rate control, rhythm control with the "least-risky" therapy that is effective for alleviating symptoms seems most reasonable, they write.