Return on investment in needle and syringe programs in Australia: report

5.5 Number of life years gained

Page last updated: 2002

The number of life years gained provides a measure of the additional number of years by those persons who would otherwise have been infected with HIV and HCV, but for the effect of NSPs. This is estimated by deducting the number of life years they would have lived with HIV or HCV from the number of years they are expected to live without the disease. The results are indicative of the effect of the mortality rate for HIV/HCV on the target population, compared to that for the same population without these diseases.

The effect of NSPs on HIV and HCV is illustrated in Figure 5.2 and Figure 5.3 with detailed tables provided in Table 5.5.1 (See Appendix E).

In the figures, the gap between the curves "Survivors without HIV/HCV" and "Survivors with HIV/HCV" represents the number of life years saved over the lifetime of those affected. As is evident from both the figures and the tables, the effect of NSPs in terms of life years saved is much greater for HIV than for HCV. The 25,000 persons avoiding HIV are expected to gain an additional 588,000 life years (about 23 years each) than if they had contracted HIV. In comparison, the 21,000 persons avoiding HCV are expected to gain only about 1,200 life years over their lifetime. The difference in these outcomes is essentially due to the different mortality rates associated with each disease and their rate of progression through the various stages, both of which have been incorporated into the analysis.

Figure 5.2 Life Years Gained for HIV cases avoided

Text equivalent below for Figure 5.2 Life Years Gained for HIV cases avoided
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Text version of Figure 5.2

Figures in this description are approximate as they have been read from the graph.

Figure 5.2 consists of two graphs.

Life years gained by survivors without HIV increases sharply from 1,000 in 1991 to 27,000 in 2001, before decreasing gradually to 20,000 in 2035 and then decreasing more rapidly to less than 1,000 in 2069.

Life years gained by survivors with HIV increases sharply from 1,000 in 1991 to 26,000 in 2001, before decreasing sharply to 10,000 in 2022 and decreasing gradually to less than 1,000 by 2057.

Figure 5.3 Life Years Gained for HCV cases avoided

Text equivalent below for Figure 5.3 Life Years Gained for HCV cases avoided
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Text version of Figure 5.3

Figures in this description are approximate as they have been read from the graph.

Figure 5.3 consists of two graphs with almost identical shapes.

Life years gained by survivors without HCV increases sharply from 7,000 in 1991 to 21,000 in 2000, before decreasing gradually to 15,000 in 2039 and decreasing sharply to less than 1,000 by 2072.

Life years gained by survivors with HCV increases sharply from 5,000 in 1991 to 21,000 in 2003, before decreasing gradually to 15,000 in 2039 and decreasing sharply to less than 1,000 by 2072.