Entete 3

Looking for a consensus for a definition of multimorbidity: the results

We have computed the results of the survey we conducted recently on the definition of multimorbidity.

We received 55 responses from 16 countries. The distribution of respondents by country (in alphabetic order) was: Australia 4, Brazil 1, Canada 10, China 1, Egypt 1, Germany 1, India 1, Indonesia 1, Ireland 6, Netherlands 4,  South Korea 1, Spain 6, Switzerland 1, Turkey 1, United Kingdom 10 (3 of them from Scotland), United States of America 6.

Answers to the question “which definition do you think should be used for multimorbidity?” were as follows:

Comments associated with the responses to the last item are shown below as replies to this posting. We welcome more comments on this subject that can also be written as replies to the posting.

We want to thank all participants who shared their view on this subject.

The International Research Community on Multimorbidity


  • 1
    Catherine Bromley
    March 6, 2014 - 9:38 am | Permalink

    I’m not sure that the proposed definitions resolve all of the complexities surrounding the conceptualisation and definition of multimorbidity. Whether conditions need to be chronic / long-term to be included is but one factor. Others include: what morbidities count? Should there be a minimum threshold for the number and / or type of morbidities that have been included in the definition? Should risk factors (such as hypertension, obesity) count as morbidities? Should social / environmental vulnerabilities and risks count? Should morbidities have to have been confirmed by / based on a doctor’s diagnosis, or should symptomatic morbidity – as reported by individuals – also be recognised? There is certainly a pressing need for greater standardisation of terms in this field, and I agree that the definition proposed by the European team has not helped. However, the range of definitions currently used might not solely be due to a lack of conceptual clarity, but also the fact that multimorbidity is not a singular concept. There are multiple forms of multimorbidity (both in terms of what actually exists, and what can be measured). This suggests that a range of definitions (or more challengingly, minimum acceptable criteria) would be preferable, with each definition making explicit the model of multimorbidity that has been adopted. Acknowledging the plural nature of multimorbidity should help researchers to clarify their terms, and sharpen the conceptual underpinning of the work they are conducting. In many instances, the definitions applied appear to be largely pragmatic, contingent on the availability of data, rather than any a priori theorisation about the topic. I’m not in a position to generate such definitions, indeed, consensus around some of the issues posed above might never be found. I simply want to raise the prospect that this might be a useful avenue to explore. My own work, for example, is attempting to address some of these issues in relation to the use of formal diagnoses and direct symptomatic reporting; the contribution of risk-factors; and the inclusion/exclusion of mental health diagnoses. My apologies for responding to your question with “more research is needed” – but I hope I have raised some useful points.

  • 2
    March 6, 2014 - 9:44 am | Permalink

    I think it is important to also consider the impact of having multiple conditions. I would favour the definition used by the US National Quality Forum: “Persons with multiple chronic conditions are defined as having two or more concurrent chronic conditions that collectively have an adverse effect on health status, function, or quality of life and that require complex healthcare management, decision-making, or coordination.” (National Quality Forum (2012), ‘Multiple Chronic Conditions Measurement Framework’, (Washington DC), 1-74).

  • 3
    March 6, 2014 - 9:46 am | Permalink

    Coexistence of 3 or more chronic diseases in the same individual.

  • 4
    Renee Lyons
    March 6, 2014 - 10:10 am | Permalink

    I agree that the issue raised by Anonymous is a very important one to consider. Are care need, and the social and mental health elements that make people complex embedded in the term, mm; or, are they added through qualifying terms and adjectives? There are pros and cons to both approaches. We tend to use the terms multiple chronic conditions, complex care, patient complexity at Bridgepoint Active Healthcare, Toronto, as they they seem more appropriate for assessing quality care and performance, and for discussions on the policy front. It’s terrific that you are working to try to address the issue of definition. Maybe a lexicon of terms is needed that descibes this area, that contributes to uniting our clinicians, researchers, data systems people and policy folks, rather than dividing them. It’s a tough one.

  • 5
    Olga McDaid
    March 10, 2014 - 7:34 am | Permalink

    There is a distinction between the definition of multimorbidity and the operational definitions required to measure the phenomenon. Both depend largely on the research question/intervention at hand and available data. As part of my PhD, I developed an approach to examining multimorbidity relevant to population health. This required delineation of the concepts of multimorbidity and comorbidity and also the operational definitions of multimorbidity to examine a range of outcomes. Given the continued confusion of conceptualisations, the default to use comorbidity as a general rather than relative term and the need for a global term to encompass all investigations of co-occurring conditions I adopted a clear distinction between the terms multimorbidity, comorbidity and the operational definition of co-occurring conditions. Examining co-occurring conditions in community-dwelling populations for a range of outcomes warrants a focus on multimorbidity, treating all conditions equally as distinct from comorbidity which is concerned with the impact of additional conditions on a condition of interest (index condition), implying a temporal relationship between conditions, more appropriate to inform clinical investigations. Retaining the definition proposed by van den Akker, multimorbidity is referred to as: ‘the co-occurrence of multiple chronic or acute conditions within one person’. The term multimorbidity is applied as an overarching global term referring to all conceptualisations of co-occurring conditions within an individual. Where relevant to analyses and interpretation, the operational definition of multimorbidity is specified as:

    Threshold multimorbidity – the co-occurrence of multiple chronic conditions within one individual measured as ≥ 2 conditions.

    Complex multimorbidity – the co-occurrence of multiple chronic conditions within one individual measured as ≥ 3 conditions.

    Physical multimorbidity – the co-occurrence of two or more physical health conditions in one individual, without a mental health component.

    Physical-mental multimorbidity – the co-occurrence of at least one physical and one mental health condition in an individual.

    Mental health multimorbidity – the co-occurrence of two or more mental health conditions in one individual.

    Concurrent counts of conditions or multimorbidity levels – increasing from 2 conditions to include all levels of multimorbidity.

    Multimorbidity clusters – non-randomly co-occurring patterns of condition associations identified in cluster analysis.

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