Understanding the burden of musculoskeletal conditions

Musculoskeletal conditions have an enormous and growing impact world wide. “Health 21,” the health for all policy framework for the World Health Organization's European region,¹ identifies musculoskeletal conditions as a target, yet national health care priorities in the United Kingdom and most European countries do not include them. To address this imbalance the United Nation, the WHO, governments, and professional and patients' organisations have declared 2000-10 the “bone and joint decade” with the aim of improving the health related quality of life of people with musculoskeletal conditions.

Although one of the aims of the decade is to increase the recognition and understanding of the burden posed by musculoskeletal conditions, there are already enough data to show the size of the problem. Musculoskeletal impairments ranked number one in chronic impairments in the United States,² and chronic musculoskeletal pain is reported in surveys by 1 in 4 people in both less and more developed countries.³ Musculoskeletal conditions were the most expensive disease category in a Swedish cost of illness study, representing 22.6% of the total cost of illness.⁴ Measured in terms of disability adjusted life years (DALYs), osteoarthritis is the 4th most frequent predicted cause of health problems worldwide in women and the 8th in men⁵; rheumatoid arthritis restricts work capacity in a third of people within the first year⁶; fractures related to osteoporosis will be sustained by about 40% of all white women aged over 50⁷; the one year prevalence of low back pain in the UK is almost 50%⁸; 23-34 million people are injured world- wide each year in road traffic accidents⁹; and work related musculoskeletal disorders were responsible for 11 million days lost from work in 1995 in the UK.¹⁰ Yet only 5% or less of national research councils' spending is allocated to musculoskeletal conditions in established market economies.

From large areas of the globe incidence and prevalence figures are rudimentary or lacking, but epidemiological studies in less developed countries¹¹ show that musculoskeletal conditions are just as important a problem as in more developed countries. The impact of musculoskeletal conditions and trauma varies between different parts of the world and is influenced by social structure, expectation, and economics. Nevertheless, with population growth and increased longevity, urbanisation, and more use of cars, the burden is increasing.

Why is the importance of musculoskeletal conditions underappreciated? Is it because they are rarely fatal, are considered irreversible, and are associated with age? Older people place a very high marginal value on maintaining independence and dignity,¹² and preventive measures and effective treatments are now available that can significantly improve the outcome of musculoskeletal conditions. However, the recently demonstrated underuse of hip and knee arthroplasty¹³ reflects the lack of knowledge, negative attitudes, and low expectations that surround these conditions.

A primary objective of the bone and joint decade is to provide, in collaboration with the WHO Global Burden of Disease 2000 Project, information on the burden caused by musculoskeletal conditions to inform debates on priorities and strategies. In addition, defining methods of measuring and monitoring these conditions will enable trends to be predicted and allow planning of research and development, training, and investment in health services.

For these largely chronic non-fatal conditions, disability assessment is more important than mortality figures, and the WHO revised classification of effects of health conditions, the ICIDH-2, provides a framework to describe these consequences and factors that may influence them. Summary measures of population health, such as disability adjusted life years (DALYs), facilitate comparisons between different conditions by combining information on mortality and non-fatal health outcomes, but estimating these for chronic, progressive conditions with variable outcomes poses challenges and can undervalue life with disability. Indicators that can also integrate evidence from randomised controlled studies with evidence gained in clinical practice to identify interventions that improve health are needed to assess the consequence of a disease for both the individual and the population.

At present few indicators relevant to musculoskeletal conditions are routinely collected either in national health statistics or by the WHO Health for All 2000 statistical databases. We need to identify such indicators and advocate their use. At the level of the individual better measures of long term morbidity need to be agreed and data collected. A recent WHO scientific group meeting considered pain, mobility, and independence to be the most relevant domains for musculoskeletal conditions, and it identified the need for simpler instruments usable in all populations to monitor these aspects. The meeting represented the first phase of a global health needs assessment exercise for musculoskeletal conditions, the bone and joint monitor project, which also aims to show what can be achieved by effective evidence based strategies to reduce the burden.

Recognition of the burden of musculoskeletal conditions will result in greater awareness of the pervasive effects they have on individuals and of their cost to society. Measuring the burden should ensure they receive higher priority in health strategies. The application of agreed indicators will allow these conditions to be monitored and interventions evaluated. In these ways understanding the burden will ultimately improve outcome for individuals.