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Tuesday, 19 October 2004 - 1:45 PM

This presentation is part of: Oral Concurrent Session B - Public Health 2

DESIGN OF AN ULTRASOUND SCREENING PROGRAM FOR ABDOMINAL AORTIC ANEURYSM USING COST-EFFECTIVENESS ANALYSIS

Marc D. Silverstein, MD, Health Care Research, West Roxbury, MA, Elliot L. Chaikof, MD, PhD, Emory University School of Medicine, Department of Surgery, Atlanta, GA, Stephen R. Pitts, MD, MPH, Emory University School of Medicine, Department of Emergency Medicine, Atlanta, GA, and David J. Ballard, MD, PhD, Baylor Health Care System, Institute for Health Care Research and Improvement, Dallas, TX.

Purpose: Randomized controlled trials of ultrasound (USG) screening for abdominal aortic aneurysm (AAA) have shown USG effective in reducing AAA related mortality but not total mortality in older men. Recent adoption of endovascular surgery (EVAR) in place of open surgical repair (OSR), patient refusal of USG, incidental discovery and early surgery for AAA, and refusal or being unfit for elective surgery could influence the cost-effectiveness of USG in clinical practice settings.

Methods: A 17-state Markov model was developed to compare USG screening for AAA to usual care by evaluating the incremental cost-effectiveness ratio (ICER), number of ruptured AAAs and AAA deaths prevented, relative risk (RR) of ruptured AAA and AAA death, and number needed to be invited (NNI) or screened (NNS) to prevent an AAA rupture or AAA death. Outcomes of a single USG screening examination of white men at age 65 with follow-up at 3, 6, 9 or 12 months for intermediate sized AAA (4.5-5.5 cm) and either EVAR or OSR for large AAA >5.5 cm) over 20 years were analyzed for a cohort of 100,000 men. Monte Carlo sensitivity analysis was performed and acceptability curves were constructed.

Results: USG screening would have prevented 764 AAA ruptures (RR = 0.69), with a NNI=131 and NNS = 105. USG would reduce total mortality by ~ 1% (764/61408). Net QALYs accrue in USG screening after 6 years and continue to occur through year 20. USG screening would have an ICER of $15,722 per QALY gained, (95% CI $14,318 – $18,177) even with follow-up of intermediate size AAA every 3 months. 95% of ICERs were < $17,625. The optimal age to initiate USG is 61; the ICER is < $20,000 per QALY for screening as early as age 55. As EVAR replaces OSR for elective AAA surgery the ICER decreases to $14,138. The ICER is not sensitive to likely ranges for refusal of screening, refusal of elective surgery, incidental discovery of AAA, or early surgery for small or intermediate size AAA.

Conclusion: One-time ultrasound screening for AAA in older men at age 65, or possibly as early as age 55, can be recommended as cost-effective in reducing risk of AAA-related mortality but would have a small impact in reducing total mortality of older white men.


See more of Oral Concurrent Session B - Public Health 2
See more of The 26th Annual Meeting of the Society for Medical Decision Making (October 17-20, 2004)