This article is more than 5 years old. Information may no longer be current.
Population screening for AAA in women 'would yield little benefit'
New data from the United Kingdom indicate that an abdominal aortic aneurysm screening program in women, based on the standards used for screening in men, was not cost-effective and could lead to overdiagnosis or overtreatment.
For this study, researchers developed a discrete event simulation model for AAA screening, surveillance and intervention using data from a combination of literature reviews, clinical trial data, bespoke hospital datasets and analysis of routine and registry data sources.
Lack of benefit
Currently, AAA screening in the United Kingdom is offered to men at age 65 years. AAA is diagnosed when aortic diameter is at least 3 cm and elective repair is considered at 5.5 cm.
When using the same protocol in women, screening detected AAA in 0.31% of the population, which led to 23% more total AAAs detected from age 65 to 95 years and 21% more elective operations than predicted to occur without screening.
AAA-related deaths were reduced by 7% during the first 10 years after screening and by 3% overall from ages 65 to 95 years. However, for every four women who did not die from AAA, one woman died due to additional elective repair. The researchers attributed an early negative effect of screening on AAA-related deaths to the high operative mortality for elective repair, noting that less than half of repairs in women aged younger than 75 years used endovascular aneurysm repair.
Overall, results showed that 3,900 women would have to be invited to screening to prevent one death due to AAA, with an overdiagnosis rate of 33%, and the incremental cost-effectiveness ratio over 30 years was £30,000 (95% CI, 12,000-87,000) per quality-adjusted life-year gained.
‘Best alternative strategy’
The researchers also evaluated the use of a “best alternative” screening strategy in which women were screened at age 70 years, the threshold for AAA diagnosis was reduced to 2.5 cm and the threshold for considering surgery was lowered to 5 cm.
Using this protocol, significantly more AAAs were detected (1.2%) and more elective repairs were performed in this scenario as compared with the reference screening strategy (1,301 vs. 452 per 1 million women invited to screening). AAA-related deaths from age 70 to 80 years and from 70 to 95 years per 1 million women and emergency operations were also reduced. However, for every seven women who an AAA-related death due to screening, two women died due to elective repair.
In this scenario, overall, 1,800 women would need to be invited to screening to prevent one death due to AAA, with the overdiagnosis rate increasing to 55%, and the incremental cost-effectiveness ratio was £23,000 (95% CI, 9,500-71,000) per quality-adjusted life-year.
Concerns remain
The researchers concluded that, “based on current evidence and definitions of AAA in men, population AAA screening of women would yield little benefit.”
Although these data suggest that screening based on AAA definitions in men would not be beneficial for women, more information on AAA in women would be helpful, according to the researchers.
“Further research on the population-based aortic size distribution in older women is needed, to provide a female-specific definition of AAA, together with better quantitative studies of the effect of screening on quality of life,” they wrote.
In an accompanying comment, Minna Johansson, MD, from the University of Gothenburg and Cochrane Sweden at Skåne University Hospital, and Karsten Juhl Jørgensen, MD, from the Nordic Cochrane Center at Rigshospitalet Department in Copenhagen, highlighted several important issues brought to light by the study.
For instance, they noted that there was uncertainty about cost-effectiveness and the potential harms related to overdiagnosis and elective surgery.
“This study indicates that screening women for AAA is not economically acceptable. The benefit-harm balance might also be ethically questionable, but this remains a value judgment. Furthermore, this study points to an urgent need for cost-effectiveness analyses for current AAA screening programmes for men that take into account both the large declines in AAA-related mortality and harms of screening such as overdiagnosis, treatment, and effects on quality of life,” they wrote. – by Melissa Foster
Disclosures: The authors report no relevant financial disclosures. Johansson and Jørgensen report no relevant financial disclosures.