This document sets out what the NIHR means when it uses the term ‘multiple long-term conditions (multimorbidity)’ (MLTC-M) and considers other terms that can be used to meet the evidence aims set out in our Strategic Framework below. We would like to create a common understanding across the MLTC-M research community to encourage research applications which address these aims.
How do we define MLTC-M?
The terms ‘multiple long-term conditions’ or ‘multimorbidity’ refer to the existence of two or more long-term conditions in a single individual. The NIHR is using the definition set out in the 2018 Academy of Medical Sciences policy report - Multimorbidity: A priority for global health research, which is:
The co-existence of two or more chronic conditions, each one of which is either:
- A physical non-communicable disease of long duration, such as a cardiovascular disease or cancer.
- A mental health condition of long duration, such as a mood disorder or dementia.
- An infectious disease of long duration, such as HIV or hepatitis C.
This definition is consistent with that adopted by the World Health Organization (WHO) and, according to the AMS report, approximates that most frequently used by researchers to date.
We recognise that the public and patients don’t understand, or like the term multimorbidity, and don’t consider themselves to be multi-morbid. The term Multiple Long-Term Conditions (MLTC) is often used, especially when speaking with patient groups and research charities as it is the preferred nomenclature for many people with MLTC and their families. With this in mind, the NIHR will also be using this term but recognise that the term multimorbidity has impetus, for example it is the term used in AMS report ‘Multimorbidity: A Global Health Priority, and in the subsequent ‘multimorbidity research funders group’, of which NIHR is a founding partner. Therefore, we will blend the two and use the term Multiple Long-term Conditions (Multimorbidity) (MLTC-M). The definition set out in the AMS report above still applies.
The ‘multimorbidity research funders group’ has also published a framework setting out how we can deliver a step-change to understand the clusters of disease, mechanisms and causes, prevention, management and treatment of multimorbidity through research was published at the end of 2019. The NIHR strategy for MLTC-M research aligns with this framework.
We are also aware that some people are living with one condition but that this affects multiple systems within the body and therefore their experience of the health and social care system is similar to people living with MLTC. For example, children with Cerebral Palsy have motor problems, visual impairment and learning difficulties. They might see a community paediatrician, physiotherapist, speech and language therapist, occupational therapist, orthopaedic surgeon, and vision, education and social services. This brings them, and their families, into contact with a range of services led and managed by different parts of the system (health, social care, education). Clearly there is complexity here, which is not defined as MLTC-M but could be described as Complex Care Needs. NIHR is content to use this term and would consider this patient/carer group eligible to be included in research covering MLTC-M if aligned with the aims set out in our strategic framework. This is particularly important in research that relates to children and young people because the AMS report excluded multimorbidity in paediatric and adolescent populations (those aged < 18 years), which may have altered the concept and definition of multimorbidity in their report for these groups.
The NIHR is taking a life-course approach to MLTC-M and we believe it is crucial that we are as inclusive as possible. While a substantially greater proportion of older people have MLTC-M, living with deprivation means that some people are more likely to have MLTC-M earlier in their lifetime. Certain periods of life, such as pregnancy, also increase the likelihood that multiple conditions present concurrently. Research funding into MLTC-M and associated needs will apply to populations at all stages of the life-course, unless stated otherwise, and we would like the research community to address this need.
In the last couple of years, The Lancet coined the term ‘syndemics’ to describe a conceptual framework for the presence of two or more disease states that could be underpinned by social, economic and environmental factors. We do not intend to use this term but would expect that all research commissioned through NIHR pertaining to MLTC-M, as set out in the strategic framework, takes a biopsychosocial approach and considers wider determinants and factors as appropriate. Research into MLTC-M should acknowledge that the impact of a condition is influenced not only by health-related characteristics but also by socioeconomic, cultural and environmental factors, and patient behaviour.
Researching MLTC-M in context
The term MLTC-M also overlaps with other concepts such as comorbidity and frailty. MLTC-M and comorbidity provide two different perspectives through which to consider a patient with more than one concurrent condition. MLTC-M is more inclusive, as it includes ‘discordant multimorbidity’, conditions which cluster but appear not to be related, and doesn’t make assumptions about which condition, or set of symptoms, is more important to the patient (in terms of quality of life). NIHR will refer to MLTC-M rather than comorbidity when commissioning calls and is particularly interested in what has been termed complex multimorbidity (four or more long-term conditions) but we will not exclude research on two conditions under the theme.
MLTC-M can also be confused with frailty but while MLTC-M is the co-existence of distinct long-term conditions, frailty is generally defined as the increased vulnerability of individuals to stressors from the accumulated consequences of morbidities or their treatments, or as part of ageing. Therefore, some but not all people with MLTC-M will be considered frail and many, but not all, with frailty will have MLTC-M.
The burden of MLTC-M and related treatments is critical and should be considered in research to ensure that we are doing the research with the populations most in need. Burden on the individual, whether that be caused by the conditions themselves, the health and social care system response, treatment or polypharmacy, is key. The NIHR appreciates that many people are living well with long-term conditions, many of which may be commonplace and manageable, and as we age this can lead to living well with MLTC-M. We’d like the balance of research to consider people who are living with MLTC-M where the burden of their multiple conditions is more than the sum of its parts.
Research commissioned within the NIHR MLTC-M strategic framework will be inclusive of conditions, in that it includes physical and mental health conditions, and single conditions which result in multisystem impacts or functional loss. The term employed in a particular project or programme will depend on the primary research objective and the problem the research is attempting to solve. Panels will assess applications to ensure that the research commissioned under the MLTC-M strategic framework is aligned with the aims set out below.
What is clear in the AMS report is that, “Inconsistent approaches to the definition……of multimorbidity have made the comparison and synthesis of findings from different research efforts challenging.” This constrains the science and makes changing the system to benefit patients more difficult. Therefore, it is crucial that research funded through NIHR is as consistent as possible in the definition of MLTC-M used in the AMS report, and that the research adds to the evidence base to meet the ambitions in the NIHR Multiple Long-Term Conditions (Multimorbidity) Strategic Framework.
In summary, the NIHR:
- will use the AMS definition of multimorbidity
- acknowledges that we can use different terms under this theme, as appropriate
- is trying to be inclusive as far as possible, especially when it comes to what matters most to patients
- is taking a life-course approach
- is focussing on the populations most in need
The Multiple Long-term Conditions (Multimorbidity) Strategic Framework
MLTC-M is a priority for the NIHR and the MLTC-M strategic framework sets our ambitions and the steps we will put in place to drive MLTC-M research forward. The aims set out below are high-level at present, we intend to build on these
The NIHR will:
Fund high quality research to provide an evidence base which:
- Identifies and maps common clusters of disease and their trajectories among the population
- Identifies the problems and outcomes that matter most to patients and carers and how they would like to see services configured to meet their needs
- Delivers research that enables the health and social care system to take a patient-centred, whole person approach to the treatment and care for people with MLTC-M, including quality of life and well-being
- Supports design and delivery of interventions to prevent patients progressing from one long-term condition to MLTC-M.
Foster a change in NIHR culture and practices to promote and enable research into MLTC-M:
- Review our funding processes (engagement, application, panel) to support applications.
- Engage with the NIHR community to provide and raise awareness of opportunities to move into research on MLTC-M or acknowledge or include a MLTC-M lens explicitly in research projects.
- Engage with delivery and implementation colleagues (e.g. NHS, Social Care, Local Authorities) to ensure that MLTC-M are recognised as challenge, and that research is pulled through into practice.
- Foster a multi-disciplinary workforce through a new generation of researchers working beyond usual single disease specialisms.
- Support and enable team science.
- Promote a common terminology around multiple long-term conditions (multimorbidity) that makes sense to funders, researchers, practitioners, patients and the public
- Ensure research and trials do not unjustifiably exclude patients with MLTC-M; facilitate better monitoring of research with a MLTC-M component; and encourage collection of appropriate and consistent outcomes measures relevant to MLTC-M.
In order to progress the research agenda in this area and deliver our strategic aims, the NIHR has set up an MLTC-M Oversight Group which:
- provides advice to help prioritise activities, identify key areas of interest and provide oversight of the implementation plan for NIHR activity in MLTC-M;
- provides a reporting mechanism and scrutiny and assurance for the workstreams being delivered through the task and finish groups;
- ensures that the NIHR communications are cohesive and internally consistent at the national level, raising the profile of the NIHR’s work in supporting research MLTC-M to demonstrate leadership in this area;
- ensures activities align with other relevant NIHR’s strategic priorities; and
- identifies opportunities and intelligence, including international initiatives, relevant to the NIHR.
Find out more about MLTC research across NIHR, MLTC as a strategic priority and how you can get involved in MLTC research.