The projected burden of arthritis among adults and children in Australia to the year 2040: a population-level forecasting study.

BACKGROUND

Understanding how many people could be living with arthritis in the future is essential for planning health service needs and national health workforce requirements, and for arthritis advocacy and policy development. This study aimed to forecast the size of different populations with arthritis in Australia and associated health system expenditure, up to the year 2040.

METHODS

In this population-level forecasting study for Australia, prevalence data for arthritis, osteoarthritis, and rheumatoid arthritis were obtained from the Australian Bureau of Statistics 2022 National Health Survey. Prevalence rates for juvenile idiopathic arthritis were sourced from 2021 Census data. Overall, age-specific and sex-specific prevalence data were applied to national population projections to forecast arthritis, osteoarthritis, rheumatoid arthritis, and juvenile idiopathic arthritis populations for 2025, 2030, 2035, and 2040. The base case analysis considered medium population growth; sensitivity analyses considered low and high growth scenarios. Health system expenditure data from the Australian Institute of Health and Welfare were extrapolated to base case projections for the years 2025, 2030, 2035, and 2040, and were then inflated to future dollars. To understand the broader context and implications of our projections through the lens of lived experience, an arthritis consumer researcher and members of the Arthritis Australia Consumer Advisory Panel reviewed the arthritis burden estimates.

FINDINGS

With population growth and ageing, 5·39 million (95% CI 5·19-5·58) people are projected to have arthritis in Australia in 2040, representing an increase of 31% from 4·11 million (3·95-4·27) in 2025. By 2040, 3·11 million (2·99-3·23) people are expected to have osteoarthritis, 749 000 (652 000-846 000) are expected to have rheumatoid arthritis, and about 8500 children and adolescents are expected to have juvenile idiopathic arthritis. The age-standardised rate of osteoarthritis is forecast to increase for males from 6·28% in 2025 to 7·03% in 2040, and for females from 10·82% to 12·18% over this period. The age-standardised rate of rheumatoid arthritis is forecast to increase for males from 1·56% in 2025 to 1·75% in 2040, and for females from 2·62% in 2025 to 2·94% in 2040. Little change is anticipated in the number of children and adolescents with juvenile idiopathic arthritis (estimated at 8500 individuals in 2040). Based on current spending levels of AU$2100 per person with osteoarthritis and $1918 per person with rheumatoid arthritis, annual health system expenditure for osteoarthritis and rheumatoid arthritis is conservatively forecast to exceed AU$11·92 billion by 2040.

INTERPRETATION

Using the latest national-level data, this study has generated contemporary projections of the substantial burden of arthritis (both population size and health-care costs) in Australia. These projections underscore the importance of well-resourced health services that can capably deliver timely, high-value care to a growing number of people with arthritis.

FUNDING

Arthritis Australia and National Health and Medical Research Council.