Implications of multimorbidity on healthcare utilisation and work productivity by socioeconomic groups: Cross-sectional analyses of Australia and Japan

Background: Multimorbidity, the presence of 2 or more non-communicable diseases (NCDs), is a major contributor to inequalities of health in Australia and Japan. We use nationally representative data to examine (i) the relationships between multimorbidity with healthcare utilisation and productivity loss and (ii) whether these relationships differed by socioeconomic groups. Methods: Cross-sectional analyses using the Household, Income, and Labour Dynamics in Australia (HILDA) and the Japanese Study of Aging and Retirement (JSTAR) surveys. We examined 6,382 (HILDA) and 3,503 (JSTAR) adults aged ≥50 years. We applied multivariable regression, logistic and negative binomial models. Results: Prevalence of multimorbidity was overall 38.6% (46.0%, 36.1%, 28.9% amongst those in the lowest, middle and highest education group, respectively) in Australia, and 28.4% (33.9%, 24.6%, 16.6% amongst those in the lowest, middle and highest education group, respectively) in Japan. In Australia and Japan, more NCDs was associated with greater healthcare utilisation. In Australia and Japan, more NCDs was associated with higher mean number of sick leave days amongst the employed and lower odds of being employed despite being in the labour force. The association between multimorbidity and lower retirement age was found in Australia only. Conclusion: Having more NCDs pose significant economic burden to the health system and wider society in Australia and Japan. Targeted policies are critical to improve financial protection, especially for lower income groups who are more likely to have multiple NCDs. These individuals incur both high direct and indirect costs, which lead to a greater risk of impoverishment. What is known and unknown: In Australia and Japan, it has been shown that more non-communicable diseases (NCDs) is associated with greater health service use.There is a lack of research in Australia and Japan on how more NCDs is associated with productivity loss, especially involuntary early retirement, absence from work due to chronic illness, and being unemployed despite being in the labour force.There are also limited studies on how the socioeconomic status of individuals in Australia and Japan influences the relationships between multimorbidity with healthcare utilisation and productivity loss. What this study adds: In both Australia and Japan, having more NCDs is associated with higher healthcare utilisation and lower work productivity, including sickness absence, unemployment and early retirement.Across all levels of income and levels of education, there was an association between number of NCDs with healthcare utilisation and work productivity loss. Targeted policies are critical to improve financial protection, especially for lower education groups who are more likely to have multiple NCDs. These individuals incur both high direct and indirect costs, which lead to a greater risk of impoverishment