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This is a plain English summary of an original research article. The views expressed are those of the author(s) and reviewer(s) at the time of publication.

Two-thirds of adults aged over 65 are expected to be living with multiple health conditions (multi-morbidity) by 2035. Seventeen percent would be living with four or more diseases, double the number in 2015. One-third of these people would have a mental illness like dementia or depression.

Increased life expectancy by around three years for both men and women means people will spend longer living with multi-morbidity.

This study, partly supported by NIHR, ran a computer model using data on over 300,000 people from three UK population surveys to predict changes in multi-morbidity between 2015 and 2035. The estimates have limitations, including self-reporting of conditions and assumptions made around changes in health status. But analyses taking account of such factors gave consistent findings.

The increase will place greater demand on all areas of health and social care and highlights the need for commissioners to ensure adequate provision of services. It also supports the on-going public health focus on health awareness and disease prevention.

Why was this study needed?

The UK has an ageing population; the number of people aged 85 or over is predicted to double in the next 20 years. People in this age group are likely to have multiple conditions, leading to greater complexity in their care, higher risk of hospital admissions and readmissions, longer hospital stays, and lower quality of life. The growing number of younger people with multi-morbidity, particularly obesity-related diseases, will contribute to the health and social care burden as they age. This presents commissioners with challenges when planning health and social care services for the future.

Previous prediction models have focused on single diseases or risk factors. This study aimed to take a wider view, providing new insight into how multi-morbidity will develop in older adults over the next 20 years.

What did this study do?

This study used data from three UK population surveys to run a computer simulation (Population Ageing and Care Simulation, PACSim) of the likely health and mortality outcomes for older adults from 2015 to 2035.

The three studies were Understanding Society, the English Longitudinal Study of Ageing, and the Cognitive Function and Ageing Study II. Over 300,000 people were included, all aged 35 or over. Data was collected on socio-demographic characteristics, health behaviours and various chronic diseases, such as cardiovascular, respiratory and mental health. The model simulated potential monthly changes to health and risk factors. They considered multi-morbidity regarding diseases or impairment (sensory, cognitive).

There is some potential for inaccuracy. Diseases are limited to those covered by the studies, and many were self-reported.

What did it find?

  • In 2015, 54.0% of people aged over 65 had two or more conditions (multi-morbidity). By 2035 this is predicted to have risen to 67.8%. By age group, the prevalence of multi-morbidity was predicted at 52.8% for people aged 65-74, 75.9% for those aged 75-84, and 90.5% for those above the age of 85.
  • By 2035, there will be double the number of people aged over 65 living with four or more conditions: 17.0% compared with 9.8% in 2015. People aged over 75 contribute most to this number.
  • By disease, most people over 65 will be affected by arthritis (62.6%), followed by high blood pressure (55.9%), respiratory disease (24.4%), cancer (23.7%) and diabetes (21.6%). The greatest prevalence increase was for cancer which had doubled from 12.6% in 2015.
  • The contribution of mental illness (depression, dementia or cognitive impairment) to overall multi-morbidity increases with the number of diseases or impairments. In 2015, 4.1% of people with two or more conditions had mental ill-health, to 34.1% of people with four or more conditions. This pattern is expected to change little by 2035.
  • Life expectancy is predicted to increase by 3.6 years for men and 2.9 years for women by 2035. This extra life comprises a reduction in years lived with no or only one health condition and an increase in years lived with multi-morbidity.

What does current guidance say on this issue?

NICE 2016 guidelines provide numerous recommendations on the clinical assessment and management of multi-morbidity, including proactive identification and assessment tools to use in primary and secondary care.

Individual management plans are recommended which consider goals, values and priorities when deciding on treatments. NICE recommend comprehensive assessment of older people with complex needs at the point of hospital admission.

NICE has a wider definition of multi-morbidity, beyond the coverage of these surveys, including frailty, chronic pain, learning disabilities, alcohol and substance misuse.

What are the implications?

Commissioners may benefit from using studies like this to plan for potential population changes and the impact on health and social care provision. Early identification of demographic shifts and increased prevalence of multi-morbidity could help identify areas for prioritisation or allocation of resources.

The current high level of multi-morbidity among younger adults highlights the need for increased public awareness and education around healthy lifestyle change and self-management of conditions.

This study highlights the need for change in traditional services organised around single conditions. Better integration of health and social care with improvements to information sharing across services may help and is likely to require long-term strategy and investment.

Citation and Funding

Kingston A, Robinson L, Booth H, et al. Projections of multi-morbidity in the older population in England to 2035: estimates from the Population Ageing and Care Simulation (PACSim) model. Age Ageing. 2018. [Epub ahead of print].

This project was funded by the National Institute for Health Research (project number ES/L001896/1) and the Economic and Social Research Council as part of their Improving Dementia Care initiative.


NICE. Multimorbidity: clinical assessment and management. NG56. London: National Institute for Health and Care Excellence; 2016.

Produced by the University of Southampton and Bazian on behalf of NIHR through the NIHR Dissemination Centre


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