Modelling the impact of multiple sclerosis on life expectancy, quality-adjusted life years and total lifetime costs: evidence from Australia

Objectives: To quantify life expectancy (LE), quality-adjusted life years (QALYs) and total lifetime societal costs for a hypothetical cohort of Australians with multiple sclerosis (MS).

Methods: A 4-state Markov model simulated progression from no/mild to moderate and severe disability and death for a cohort of 35-year-old women over a lifetime horizon. Death risks were calculated from Australian life tables, adjusted by disability severity. State-dependent relapse probabilities and associated disutilities were considered. Probabilities of MS progression and relapse were estimated from AusLong and TasMSL MS epidemiological databases. Annual societal (direct and indirect) costs (2017 Australian dollars) and health-state utilities for each state were derived from the Australian MS Longitudinal Study. Costs were discounted at 5% annually.

Results: Mean (95% confidence interval (CI)) LE from age 35 years was 42.7 (41.6-43.8) years. This was 7.5 years less than the general Australian population. Undiscounted QALYs were 28.2 (26.3-30.0), a loss of 13.1 QALYs versus the Australian population. Discounted lifetime costs were $942,754 ($347,856-$2,820,219).

Conclusion: We have developed a health economics model of the progression of MS, calculating the impact of MS on LE, QALYs and lifetime costs in Australia. It will form the basis for future cost-effectiveness analyses of interventions for MS.