What is multimorbidity and why is it important to monitor?
Multimorbidity refers to living with 2 or more chronic conditions at the same time.
Chronic conditions generally have long-lasting and persistent effects. They are also known as chronic diseases, long-term health conditions or non-communicable diseases.
Living with multimorbidity is common and becomes more common with increasing age and with risk factors including poor diet and smoking. The proportion of the population living with multimorbidity is also increasing and has increased at a greater rate than the proportion of the population living with one chronic condition only (AIHW 2024).
Care for people with multimorbidity is often challenging and complex, requiring approaches that move beyond treating individual diseases. Effective treatment and management of multimorbidity involves the coordination of health professionals, specialists and services across multiple parts of the health care system.
Living with chronic conditions can have a substantial impact on a person’s quality of life and workforce participation as well as mortality outcomes – the effect is even greater for people living with multimorbidity.
Multimorbidity, therefore, presents an important and growing challenge for individuals, the health system and society as a whole.
What’s the difference between multimorbidity and comorbidity?
The concepts of multimorbidity and comorbidity provide different ways to describe the co-occurrence of chronic conditions.
Multimorbidity analysis considers all the conditions that co-occur within an individual, without focus being given to any particular condition.
In contrast, the concept of comorbidity focuses on a primary condition of interest (an index condition), with additional conditions listed and understood in relation to the primary condition (as comorbidities).
These two interrelated concepts provide complementary ways to describe the patterns of multimorbidity and associations between different chronic conditions.
AIHW (Australian Institute of Health and Welfare) (2024) The ongoing challenge of chronic conditions in Australia, AIHW, Australian Government, accessed 12 May 2025.