Multimorbidity, health and aging in Canada and Australia: a tale of two countries

BACKGROUND: Multimorbidity has been recognized as a major public health issue, negatively affecting health-related quality of life, including physical, functional, mental, emotional, and social domains, as well as increasing health care utilization. This exploratory study examines selected health outcomes associated with multimorbidity across older age groups/cohorts and gender, comparing Canada and Australia. METHODS: Data were drawn from the 2008/09 Canadian Community Health Survey and the 2009 Australian HILDA survey. Seven major chronic conditions were identical across the two data sets, and were combined into an additive measure of multimorbidity. OLS and logistic regression models were performed within age group (45-54, 55-64, 65-74, 75+) and gender to estimate associations between multimorbidity and several health-related outcomes, including: loneliness, life satisfaction, perceived health, mobility restriction, and hospital stays, adjusting for marital status, education and foreign born status. RESULTS: Overall, country-level differences were identified for perceptions of loneliness, life satisfaction, and perceived health. Australians tended to experience a greater risk of loneliness and lower self-rated health in the face of multimorbidity than Canadians, especially among older men. Canadians tended to experience lower life satisfaction associated with multimorbidity than Australians. No country-level differences were identified for associations between multimorbidity and hospital stays or mobility limitations. CONCLUSIONS: The associations between multimorbidity and health are similar between the two countries but are variable depending on population, age group/cohort, and gender. The strongest country-level associations are for indicators of health-related quality of life, rather than health care or mobility limitation outcomes.