In this book, we have tried to describe and discuss the key issues in multimorbidity. We have explained the ways in which multimorbidity can be defined and measured (Chapter 1), and how this influences estimates of prevalence. However measured, multimorbidity is common and likely to become more prevalent as populations age (Chapter 2). In people with long-term conditions, multimorbidity is the norm rather than the exception, and the wide range of combinations of conditions that exist challenges the current single-disease paradigm.

Multimorbidity is not just a problem of old age, and more people below the age of 65 have multimorbidity than those aged 65 years and over. This is because of the population demographics at present. Multimorbidity is socially patterned, being common in areas of higher socioeconomic deprivation. It also occurs 10–15 years earlier in the poorest communities than when compared with the most affluent in society (Chapter 2).

Multimorbidity has profound effects on quantity and quality of life, impacting negatively on functional status and quality of life (Chapter 3). It is associated with huge healthcare costs in both primary and secondary care due to higher consultation rates, more frequent hospital admissions and increased duration of stay (Chapter 4).

Primary care clinics are not well organized for the care of multimorbid patients who can seem like square pegs in round holes. There are issues of identification, continuity of care and polypharmacy resulting from the indiscriminate use of single-disease guidelines and protocol-driven consultations (Chapter 5). More than any other group, multimorbid patients require a holistic, patient-centred care tailored to the needs of the individual not their diseases (Chapter 6).