The report from the Academy of Medical Sciences, published today, points to an alarming lack of information about multimorbidity, where a patient suffers several diseases simultaneously.

While it is well known that multimorbidity is common and on the rise, the exact extent of the problem and the rate at which it is growing is not understood. It is reported to affect anywhere between 13-95% of patients globally, a range so wide that it indicates just how little is known about this global burden. The causes of multimorbidity are poorly understood and strategies for its prevention are lacking.

The report, produced by a working group of 17 international health experts, is the first to address the problem of multimorbidity on a global scale and highlights the inadequacy of the evidence required to guide health policy and medical practice. The project was supported in part by the UK Department for Business, Energy and Industrial Strategy.

Dr Lynne Corner, from the Newcastle University Institute for Ageing and the National Innovation Centre for Ageing was on the report's working group. She said: “It can be a full time job being a patient as it’s not unusual for someone to have five different appointments on five different days with five different teams and that can be really difficult to manage.

“Health services needed to be reorganised around the needs of those with multiple health conditions such as the CRESTA clinic in Newcastle, where a variety of experts in different disciplines come together to treat the person.”

Coping with multiple illness

Most health services, including the NHS, are not designed to care for patients with multiple illnesses. This is likely to contribute to the increasing pressures on health systems and budgets worldwide, the report suggests. It concludes that without a better understanding of multimorbidity, it will not be possible for any country to plan future healthcare resources and redesign services effectively. 

Health conditions that frequently group together include heart disease, high blood pressure, diabetes, cancer, depression, anxiety, chronic obstructive pulmonary disease (COPD) and chronic kidney disease. However, it is unclear why some of these conditions cluster together, making it difficult to predict which patients may be most in need of preventive steps or increased care.

Evidence suggests multimorbidity is most common in women and people with low income, and is increasingly common in young people as well as in older people.

Professor Stephen MacMahon FMedSci, Chair of the Academy of Medical Sciences multimorbidity working group, said: “While we know multimorbidity is very common, we don’t know precisely how many people live with multiple serious illnesses. From what we do know, I estimate tens of millions of Britons suffer from multimorbidity, and globally the number could be a billion. Similarly, while we know multimorbidity is increasing, we don’t know how quickly or which groups are experiencing the biggest increases.

“This report should be the tipping point of recognising that multimorbidity is an enormous threat to global health. It is a priority to get the evidence we need to develop effective strategies for prevention and treatment.”

Adapting healthcare systems

The scientific community does not have an agreed definition of multimorbidity, which has hindered essential research needed to improve prevention and treatment. The report provides a new definition of multimorbidity and recommends that this be adopted by researchers globally.

Physical and mental health conditions often cluster together. Poor mental health can negatively affect quality of life and life expectancy more so than having multiple physical illnesses. The report highlights evidence that mental health conditions can lead to reduced physical health and vice versa. For example, type 2 diabetes has been reported to increase the risk of depression, and adults with depression are 37% more likely to develop type 2 diabetes. However, the division between health services treating mental and physical health often means that patients suffering from both physical and mental conditions are at particular risk of poor care.

Clinical trials of new medicines often exclude patients with multiple conditions, leaving significant gaps in knowledge about effective treatments of those with multimorbidities. This could raise questions about the applicability of the evidence on which drugs are used, given that many long-term diseases do not exist in isolation.

The scale of multimorbidity also raises questions about the suitability of healthcare systems which are organised around treating single diseases or individual organs, the norm in most major hospitals. It also raises questions about the way in which general practice is organised – specifically whether individual GP consultations are generally too short to enable comprehensive management of multiple conditions.

Professor Stephen MacMahon added: “How to prevent and manage multiple diseases is a challenge that GPs face every day, yet we have almost no evidence on which to provide guidance as to how to do this most effectively.

“We are facing a tidal wave of patients living with multiple long-term health conditions, and our report demonstrates how little we know about how to manage this. Outcomes appear to be worse in these patients and yet there is growing evidence that people with multimorbidity are less likely to receive appropriate care for the individual diseases they have.  We face a situation where those in greatest need are least likely to receive appropriate care.

“For too long we’ve focussed almost exclusively on the management of single diseases, such as cancer and HIV.  This means we have neglected the reality that most people with any one long-term disease typically have others.”

To read 9 things you need to know about the Academy of Medical Sciences report and to download the AMS report

(Adapted with thanks from the Academy of Medical Sciences)