Principles of multimorbidity

• Having multiple chronic diseases (multimorbidity) is the leading cause of illness, disability and death in Australia.
• An estimated half of all general practice patients have two or more chronic diseases.
• The prevalence of chronic disease is associated with a substantial decrease in quality of life and affects individual independence.
• General practitioners (GPs) have a critical role in the provision of contextual continuity of care. Continuity of care, ideally with the same GP or GPs within the same general practice, has been associated with improved outcomes and lower rates of hospital presentation.
• Multimorbidity challenges the traditional medical model of healthcare.
• Actual disease burden and polypharmacy are specific challenges for the patient, carers and healthcare providers.
• Shared decision making with the patient and carers should be optimised, including a discussion around risks and benefits of investigation/intervention.

Ageing affects an individual’s health and functionality and has resource implications. Commonly, older patients are likely to experience issues with organ failures, neurodegenerative issues and/or cancer-related issues.

Having multiple chronic diseases (multimorbidity) is the leading cause of illness, disability and death in Australia, accounting for about 85% of the total burden of disease. Approximately 75% of deaths have chronic disease as an underlying cause.

The most common definition of multimorbidity is the presence of two or more chronic diseases in an individual. However, a 2016 review of Bettering the Evaluation and Care of Health (BEACH) data on the prevalence of complex multimorbidity in Australia suggested that this definition was too narrow, as it failed to identify patients who required more complex care.¹

An estimated half of all general practice patients have two or more chronic diseases. The prevalence of chronic disease increases to 74.6% for people aged 65–74 years and 83.2% in people aged ≥75 years. The prevalence of chronic disease is associated with a substantial decrease in quality of life and impacts on individual independence.¹

‘Part B. Principles of multimorbidity’ highlights the essential components of providing healthcare to older people in both residential aged care facilities (RACFs) and those in the community, while complementing Part A. Multimorbidity, which focuses on assisting in clinical decision making.

As the number of older patients entering RACFs steadily increases, the management of chronic disease and multimorbidity will be the norm. The role of general practitioners (GPs) will therefore be the most critical aspect in the provision of quality medical care.

The flow-on effects to health funding are considerable at the later stages of life; approximately 70% of the health dollar in Australia is spent on patients in their last five years of life.

There is a multitude of complex risk factors for developing chronic diseases (refer to Part A. Palliative and end-of-life care). The illness trajectories reflect:

• Prolonged illness over a long timeframe
• Long latency period
• Recurrent ‘dips’ in health status

All three trajectories have an effect on functionality and autonomy with age-related homeostatic changes also contributing.

Multimorbidity challenges the traditional medical model of healthcare, which has customarily focused on the ‘one’ disease model. Instead, multimorbidities have a tendency to ‘cluster’ according to conditions (eg cardio-metabolic conditions, osteoarthritis).

Most research to date has focused on a specific disease and pathology as standalones. Extrapolating effective interventions to the management of complex comorbidities is often problematic. Available guidelines and resources are often single-disease specific, and have to evolve to encompass the challenges of multimorbidity.² Optimum management therefore challenges the traditional model of care.

Actual disease burden and polypharmacy are specific challenges for the patient, carers and healthcare providers.

Unplanned care is common and mitigating circumstances need regular appraisal with all the members of the patient’s healthcare team (refer to Part B. Collaboration and multidisciplinary team-based care ).

A further complicating factor is cognitive decline; dementia is the single greatest cause of disability in Australians aged ≥65 years (refer to Part A. Dementia). Depression is also present in approximately 30% of this group of patient population (refer to Part A. Mental health).

Role of general practice in multimorbidity

GPs have a critical role in the coordination of care of all patients, especially older patients whose care is often more complex and challenging. Appropriate time needs to be allocated to seeing the patient to reflect their complexity, and shared decision making with the patient and carers should be optimised. Risks and benefits of any intervention needs open and frank discussion. Refer to Box 1 for a list of questions to consider before doing any tests, treatments or procedures.³

Continuity of care, ideally with the same GP or GPs within the same general practice, has been associated with improved outcomes, and is associated with lower rates of hospital presentation.

A discussion around managing the effect of the comorbidities on quality of life and day-to-day functionality is paramount. It is important to ask what the aim of a particular intervention is before starting the intervention.

This discussion will help facilitate shared decision making and promote discussions around quality-of-life issues, and advance care planning. Formal documentation reflecting the conversation/consultation should be available to all relevant parties. This is especially critical on admission to an RACF.