Counting the cost of premature mortality with progressively worse aortic stenosis in Australia: a clinical cohort study

Abstract

Background: Aortic stenosis is the most common cardiac valve disorder requiring clinical management. However, there is little evidence on the societal cost of progressive aortic stenosis. We sought to quantify the societal burden of premature mortality associated with progressively worse aortic stenosis.

Methods: In this observational clinical cohort study, we examined echocardiograms on native aortic valves of 98 565 men and 99 357 women aged 65 years or older across 23 sites in Australia, from Jan 1, 2003, to Dec 31, 2017. Individuals were grouped according to their peak aortic valve velocity in 0·50 m/s increments up to 4·00 m/s or more (severe aortic stenosis), using 1·00-1·99 m/s (no aortic stenosis) as the reference group. Sex-specific premature mortality and years of life lost during a 5-year follow-up were calculated, along with willingness-to-pay to regain quality-adjusted life years (QALYs).

Findings: Overall, 20 701 (21·0%) men and 18 576 (18·7%) women had evidence of mild-to-severe aortic stenosis. The actual 5-year mortality in men with normal aortic valves was 32·1% and in women was 26·1%, increasing to 40·9% (mild aortic stenosis) and 52·2% (severe aortic stenosis) in men and to 35·9% (mild aortic stenosis) and 55·3% (severe aortic stenosis) in women. Overall, the estimated societal cost of premature mortality associated with aortic stenosis was AU$629 million in men and $735 million in women. Per 1000 men and women investigated, aortic stenosis was associated with eight more premature deaths in men resulting in 32·5 more QALYs lost (societal cost of $1·40 million) and 12 more premature deaths in women resulting in 57·5 more QALYs lost (societal cost of $2·48 million) when compared with those without aortic stenosis.

Interpretation: Any degree of aortic stenosis in older individuals is associated with premature mortality and QALYs. In this context, there is a crucial need for cost-effective strategies to promptly detect and optimally manage this common condition within our ageing populations.

Funding: Edwards LifeSciences, National Health and Medical Research Council of Australia, and the National Heart, Lung, and Blood Institute.

Figure 1:. Profile of progressively worse aortic stenosis and associated 5-year all-cause mortality in men

This figure shows the proportion of men in each Vmax group (second level), and mortality outcomes based on the number who died during 5-year follow-up (third level), the proportion of premature deaths occurring before the age of 80·7 years (fourth level) and the associated total and mean years of life lost (fifth level) including 95% CI. Median (interquartile) years of follow-up from last echocardiogram to study completion was 6·1 (IQR 3·9–10·2) for no aortic stenosis, 6·4 (4·0–10·2) for mild aortic stenosis, 6·8 (4·2–10·6) for mild-to-moderate aortic stenosis, 7·4 (4·5–10·9) for moderate aortic stenosis, 7·6 (4·7–11·2) for moderate-to-severe aortic stenosis, and 8·7 (5·3–11·7) for severe aortic stenosis years. Vmax=peak aortic valve velocity. YLL=years of life lost.

Figure 2:. Profile of progressively worse aortic stenosis and associated 5-year all-cause mortality in women

This figure shows the proportion of women in each Vmax group (second level), and mortality outcomes based on the number who died during 5-year follow-up (third level), the proportion of premature deaths occurring before the age 84·9 years (fourth level) and the associated total and mean YLL (fifth level) including 95% CI. Median (interquartile) years of follow-up from last echocardiogram to study completion was 6·1 (3·9–10·0) for no aortic stenosis, 6·4 (4·0–10·1) for mild aortic stenosis, 6·8 (4·9–10·5) for mild-to-moderate aortic stenosis, 7·5 (4·6–10·8) for moderate aortic stenosis, 7·9 (4·9–11·1) for moderate-to-severe aortic stenosis, and 7·8 (4·8–11·1) for severe aortic stenosis. Vmax=peak aortic valve velocity. YLL=years of life lost.

Figure 3:. Sex-specific cost of premature mortality in cases with any form of aortic stenosis (n=39 277)

This figure shows the economic cost of premature mortality (based on willingness-to-pay per quality adjusted life-year) during fixed 5-year follow-up according to progressively worse aortic stenosis observed within the National Echo Database of Australia cohort. The mean number of YLL per person and total premature deaths within each group is also presented. Vmax=peak aortic valve velocity. YLL=years of life lost.