PRM44 Increasing Life Expectancy: Implications for Cost-Effectiveness Analysis

Abstract

In developed countries mortality in the general population has been declining for several decades and is anticipated to decrease further, especially among the elderly. Life tables based on national statistics reflect mortality conditions of a particular year and therefore do not take into account that survival increases in the general population. As a consequence, life tables seem to systematically underestimate overall survival of the general population. Health economic models use life tables to predict survival of the general population and may therefore also underestimate survival. Our study compares survival prediction methods and discuss implications for health economic models. Period life expectancy at age 50 calculated from Dutch mortality rates published for 2009 was compared with life expectancy of a cohort aged 50 in 2009 calculated from projected mortality rates forecasted by the standard Lee-Carter approach. The Lee-Carter model forecasts the level and age pattern of mortality based on the combination of singular value decomposition of mortality rates and statistical time series methods. Mortality rates were taken from the Human Mortality Database. Projections were based on historical data between 1970 and 2009. Based on projected mortality, cohort life expectancy was 34.97 years whereas period life expectancy was only 32.37 years (−2.60 years). When life years were discounted at a 1.5% rate, the corresponding values were 25.31 and 26.40 years (−1.09 years). The analyses shows that taking into account the decrease in survival over time results in a difference of 7% in undiscounted and 4% in discounted life expectancy in the Netherlands. This difference can have a substantial impact on cost-effectiveness results, especially of curative interventions for diseases that are life threatening or of prevention programmes over a long time horizon. In these cases, sensitivity analysis should be carried out to investigate the impact of decreasing mortality.