- Wu WC, Rathore SS, Wang Y, Radford MJ, Krumholz HM. Blood transfusion in elderly patients with acute myocardial infarction. N Engl J Med. 2001;345:1230-6.
Cost-effectiveness of Rhythm Versus Rate Control in Atrial Fibrillation
Marshall DA, Levy AR, Vidaillet H, et al. Cost-effectiveness of rhythm versus rate control in atrial fibrillation. Ann Intern Med. 2004;141:653-61.
Atrial fibrillation is the most common arrhythmia treated by physicians. It afflicts nearly 10% of patients age 80 years or older. There are two primary modalities of managing patients with atrial fibrillation; rate control versus cardioversion into sinus rhythm.
AFFIRM was a multicenter randomized controlled trial involving 213 centers in USA and Canada that compared rate versus rhythm control in 4060 patients. These patients had a mean age of 70 years. Sixty-one percent of the enrolled patients were men, and 66% had recurrent atrial fibrillation. Seventy-one percent of patients had hypertension, 39% had coronary artery disease, and 9% had congestive heart failure. Patients were block randomized by center to either rate control or rhythm control and followed for an average of 3.5 years. AFFIRM results showed no significant mortality difference between the two groups (hazard ratio for rate versus rhythm control, 0.87 with 95% CI, 0.75 to 1.01).
Primary data on survival and resource utilization were used to conduct the economic analysis from a third party payer perspective. Authors used intention to treat data for the economic analysis.
For resource utilization estimates, US healthcare cost figures for the year 2002 were used. All earlier costs were appropriately adjusted using Consumer Price Index, Medical Care component to estimate their nominal values in year 2002. Hospital costs were taken as the mean charges per day from Healthcare Cost and Utilization Project statistics for Diseases of the Circulatory System for patients older than 18 years age. Low and high end of these costs were assumed to be equivalent to 25th and 75th percentiles of the mean costs, respectively. Physician costs were assumed to be equivalent to be the average of all carriers’ payments for the relative value units of the services rendered based on a generic current procedural terminology code. Sensitivity analysis was conducted on these physician costs using minimum payment among these carriers as the low cost estimate and the standard charges for Marshfield Clinic for the high end. Costs of pacemaker and implantable cardioverter defibrillators were based on manufacturers’ list prices. For sensitivity analysis, hardware costs were excluded for low cost estimates and the maximum manufacturers’ list price for the high estimate was used.
At each follow-up visit during the AFFIRM trial, the number of cardioversion attempts since the prior visit was recorded. Costs of cardioversion were based on average payment to Marshfield Clinic for outpatient electrical cardioversion for the year 2002. Authors assigned no costs for low cost estimate and used billed charges for high costs for sensitivity analysis.
At each follow-up visit, the number of short stay and emergency department visits since the prior visit was recorded. Weighted average Medicare costs for level I and II facilities were used as the baseline estimate for these visits. Estimates for sensitivity analysis were the minimum and maximum Medicare payments for these visits. Physician fees were based on level III emergency department visit with low and high cost estimates assigned as described above.
Medication costs were based on the least average wholesale price (AWP) for a generic medication. Low and high cost estimates were taken from lowest quoted US Internet pharmacy price and highest AWP for the most expensive drug in the class respectively. Only medications used for atrial fibrillation and anticoagulation were considered for analysis.