Multimorbidity and health-related quality of life amongst Indigenous Australians: A longitudinal analysis

Background: The burden of multimorbidity has been observed worldwide, and it has significant consequences on health outcomes. In Australia, health-related quality of life (HRQoL) is comparatively low amongst Aboriginal and/or Torres Strait Islanders. Yet no studies have examined the association between multimorbidity and HRQoL within this at-risk population. This is the aim of the present study. Methods Longitudinal data were derived from three waves (9, 13 and 17) of the Household, Income and Labour Dynamics in Australia Survey. A total of 1,007 person-year observations from 592 Aboriginal and/or Torres Strait Islanders aged 15 years and above were included. HRQoL was captured using the 36-item Short-Form Health Survey (SF-36), and multimorbidity was defined as having two or more chronic health conditions. A random effects tobit model was used to assess the associations between multimorbidity and HRQoL. Results Approximately 21% of Indigenous Australians were classified as experiencing multimorbidity. Respondents with multimorbidity reported lower scores than their counterparts without multimorbidity on the SF-36 sub-scales, summary measures and health utility index. Multimorbidity had pronounced adverse effects on overall HRQoL, including on the SF-36 physical component scale (β = −3.232; 95% CI: −4.734 to − 1.730), mental component scale (β = −5.625; 95% CI: −7.435 to − 3.815) and short-form six-dimension scale (β = −0.061; 95% CI: −0.082 to − 0.041). Conclusion This study demonstrated that having two or more chronic diseases is significantly associated with lower HRQoL amongst Indigenous Australians. Advanced health strategies addressing foreseeable challenges imposed on multimorbid adults should be implemented to improve the HRQoL of Indigenous Australians.