Multimorbidity – the New Epidemic

Multimorbidity is a relatively new word in the clinical lexicon – what is it?

It is commonly defined as the presence of two or more chronic medical conditions in an individual. It can present challenges in care particularly with higher numbers of coexisting conditions and related polypharmacy.

These conditions may include recognized Chronic Disease problems such as Diabetes, Heart disease, Chronic Airways Disease and Osteoarthritis, but also

Mental Health problems

•ongoing conditions such as learning disability

•symptom complexes such as frailty or chronic pain

•sensory impairment such as sight or hearing loss

•alcohol and substance misuse.

How common is it?

A 2008–2009 BEACH sub-study that measured the prevalence of multiple chronic condition at GP consultations found that of the 8707 patients sampled from 290 GPs, approximately half (47.4%, 95% CI: 45.2–49.6) had two or more chronic conditions. Figure 1 shows that the proportion of patients with multiple chronic conditions at encounters rises significantly with age; about 90% of patients aged 80 years or more had two or more chronic conditions, while nearly 30% had seven or more. (Ref 1)

Figure 1. Proportion of patients with different numbers of multiple chronic conditions at GP encounters by patient age

This suggests that we should reconsider our current health care system’s focus on single diseases.

“The Single Condition Model” in medicine

Most research is designed to show the effect of interventions in single conditions. Those with multiple conditions are excluded to avoid confounding the data. Guidelines are designed in general to guide management in single conditions. But if we follow these guidelines in multimorbid clients and sum all the interventions together, we end up with a significant “treatment burden”.

As an example – consider the following situation:

Mrs F• 79 years old with multiple conditions including:

• osteoporosis

• osteoarthritis

• diabetes type II


• hypertension

If evidence based “Best Practice” treatment were followed, she would require:

• 12 different drugs in 19 dosages at five points in a day

• 14 different non-pharmacological interventions (rest,exercise, shoes, avoid exposure to allergens)

• nutrition: reduce intake of salt, potassium, cholesterol, Magnesium, Calcium, calories, alcohol

at least 5 doctor visits per year.

These multiple interventions are complex, difficult for both client and providers to deliver, are expensive and carry the risk of interactions which may cause harm.

Due to the “single condition” model of most research, we have little or no evidence that the interventions will be beneficial in this specific situation.

Multimorbidity and Clinical Reasoning

The study of Clinical Reasoning attempts to analyse the thought processes of a clinician when dealing with clinical problems. The “single issue” presentation is well studied – the potential traps and cognitive biases are well understood. One Clinical Reasoning framework was described by Murtagh (Ref 2 ). But the research quoted above would suggest that a single issue “diagnostic” presentation is increasingly uncommon. Many presentations involve managing multiple known problems and balancing priorities. This appears to be a “higher order” task – it has been generally left to sophisticated clinicians. The General Practitioner is uniquely qualified for this role. A broad medical knowledge and a long term relationship with the client combined with the relevant legal authority makes him/her an “Expert Generalist”.

But there appears to be little relevant research – the GP is making these decisions intuitively. Should we develop a formal model of Clinical Reasoning in this space?

The Rise of Machine Driven Care

In recent years there has been a view among many that treating long term conditions such as Hypertension, Diabetes and raised Cholesterol “to target” results in reduced Cardiovascular risk.

If a programme of interventions such as measuring blood pressure, testing blood sugar and measuring weight is delivered on a regular basis outcomes are improved. But there is “Therapeutic Inertia” which must be overcome – the measurements must be “treated to target” regardless of side effects or other reasons for not doing so. Doctors in particular have been regarded as being responsible for “Therapeutic Inertia”.

This idea is attractive because it can be delivered by less sophisticated clinicians. Careplans are devised with schedules of interventions – if they are followed there will be less emergency attendances. There is reasonably good evidence for this approach. (Ref 3)

But what about the Multimorbid clients? Can we devise Careplans to suit them? If we sum together all the interventions suggested by “Best Practice”, we create a complex matrix which in practice often is not delivered. Whats more, every client seems to have a different combination of Chronic Problems – it is impossible to devise “off the shelf” careplans to fit all. The electronic record systems that create these Careplans are not sophisticated enough to allow easy editing or to devise individualized Careplans.

Again it falls to the “Expert Generalist” GP to rationalize these complex plans and to reduce the medication and intervention burden that seems to build up like barnacles encrusting an old boat.

In my view we need to recognize the limitations of our “single issue” approach, develop electronic systems to manage multiple problems in a rational way and study the impacts of complexity and “noise” on safety and outcomes.

We should also develop models of Clinical Reasoning for this mode of practice.


  1. Australian Family Physician Volume 42, No.12, December 2013 Pages 845-845
  2. A Safe Diagnostic Model Ch 9 John Murtagh’s General Practice
  3. The cost-effectiveness of primary care for Indigenous Australians with diabetes living in remote Northern Territory communities Susan L Thomas, Yuejen Zhao, Steven L Guthridge and John Wakerman Med J Aust 2014; 200 (11): 658-662. || doi: 10.5694/mja13.11316

Author: Richard Hosking

GP Alice Springs Remote Health Music Electronics Amateur Radio

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