April 2000 Bulletin

Global Monitor Project gets underway

International group of experts to measure burden of bone and joint disease

The ability to measure the worldwide burden of musculoskeletal disease–its impact on individuals, family and society–is vital to the success of the Bone and Joint Decade. Current data indicates that musculoskeletal conditions affect hundreds of millions of people, at a huge cost to society–estimated at $215 billion per year in the United States alone. But until international statistics are available, the true global burden will remain unknown, and priorities for change cannot be established.

Musculoskeletal conditions are "underrecognized, underappreciated and underresourced," says Anthony D. Woolf, PhD, chair of the working group for the Bone and Joint Decade Monitor Project–a group that is working to correct this problem. In coordination with the World Health Organization (WHO), the Bone and Joint Decade Monitor Project working group is currently reviewing and collating data on the burden of musculoskeletal conditions globally. The project’s aim is to identify the burden of musculoskeletal conditions, determine what can be done, what is being done, and to develop strategies for prevention and treatment.

The project’s initial phase is identifying the global burden of these conditions–in collaboration with the WHO Global Burden of Disease 2000 Project, World Bank Global Road Safety Partnership and an international network of collaborators. To facilitate the collection of these important data, the Monitor Project and WHO sponsored a scientific group meeting, "The Burden of Musculoskeletal Conditions at the Start of the New Millennium," in Geneva, Switzerland on Jan. 14-15, 2000. The meeting coincided with the decade’s official "kickoff" celebration.

"Musculoskeletal conditions are among the most common medical conditions, with a substantial influence on health, quality of life and the use of resources," said Lars Lidgren, MD, PhD, chairman, department of orthopaedic surgery, Lund University in Sweden, who initiated the Bone and Joint Decade initiative. He told the January meeting that "medicine, more and more based on sophisticated technology, is becoming very expensive. At the same time, the world is aging–the number of individuals over the age of 50 is expected to double between 1990 and 2020. However, this burden is not well quantified and insufficient information exists concerning the impact that interventions have on health."

The purpose of the meeting was to bring together parties from around the world who could offer their perspectives, and to try to come to a consensus about how to measure the burden of musculoskeletal disease, says Cynthia Shewan, PhD, director of the AAOS department of research and scientific affairs, and the only U.S. member of the Monitor Project working group. In terms of measuring the burden of disease, the meeting’s goals were threefold: to determine the incidence and prevalence of musculoskeletal conditions; to develop models or "stages" for the conditions; and to determine health and economic indicators.

Joseph D. Croft, president of The American College of Rheumatology, left, discusses the Bone and Joint Decade with Stuart L. Weinstein, MD, chairman of the AAOS Bone and Joint Decade Committee.

Due to the 1999 AAOS publication, Musculoskeletal Conditions in the United States, Joseph A. Buckwalter, MD, chairman, AAOS Research Council, says, "We had a lot of information compared to any of the other groups that showed up. This had a very strong impact on the overall meeting." Dr. Buckwalter served on the panel for osteoarthritis. Other Academy members active at the meeting were Peter C. Amadio, MD, who served on the rheumatoid arthritis panel; Bruce D. Browner, MD, a member of the International Bone and Joint Decade steering group, who served as the coordinator of the panel on trauma; and Stuart Weinstein, MD, chairman of the Bone and Joint Decade Committee, who served on the spine panel.

When discussing the incidence and prevalence of musculoskeletal conditions, the meeting participants focused on five major areas–osteoarthritis, rheumatoid arthritis, osteoporosis, spinal disorders and severe limb trauma. One major outcome of the conference was the consensus that the group needs to expand beyond these five areas, adding conditions such as gout, osteomalacia and fibromyalgia, among others.

The second primary area of discussion was the need to develop models for the various musculoskeletal conditions. In other words, what happens in the course of a particular disease?

"Defining musculoskeletal conditions is a challenge," Shewan says. "We’re making progress on this issue, but there are difficulties, such as the fact that musculoskeletal conditions can be defined at various levels–symptom or diagnosis.

"Take osteoarthritis. We need to determine where this condition begins and where it ends up. What’s the time-course for that progression? What are the stages you would expect? Then the idea is to link that up with the incidence and prevalence data.

"For example, out of 40 million people with osteoarthritis, how many are in stages one, two, three or four? How do you define those stages and how long would you expect persons to be in stage one before they go to stage two?"

Also, the burden to society is different at each stage, Shewan adds. "For some diseases, stage one places no burden on society–it may require just an aspirin. But stage two may become more complicated, requiring visits to physicians, and you’ll start to see some use of resources," she says. "So these models allow you to get a much more detailed and accurate picture of what the prevalence of any given condition looks like."

The third aspect of measuring the burden of disease concerns health and economic indicators. The essential health domains to include in the measurement of musculoskeletal conditions emerged at the meeting as: pain, self-care, social role, emotional status and physical health.

"One of the goals regarding health and economic indicators is to decide how to measure the health of individuals with musculoskeletal conditions," Shewan says. "The WHO is currently looking at multi-attribute approach. Such an approach first requires deciding which health domains you want, or need, to measure.

"In the physical health domain, you may want to measure mobility," Shewan says. "And, in the mental health domain you may want to measure anxiety. For each of these domains you want to know how well or at what level a person is functioning. So you assign a level or a number to each of the domains that you’re measuring. The levels at which a person is functioning across the domains you’re measuring is called ‘health states.’

"Values" may also be assigned to these health states. Doing this allows you to compare the value of a current health state vs. "death" or "normal health."

"You can assign this particular health state a value between 1-100," Shewan says. "Then take the number of people in these various health states along with the values that have been assigned to those health states and convert them into a measure that takes into account premature death and reduced health-related quality of life."

An example of such a measure is disability-adjusted life years (DALYs). With such a measure, you can compare across musculoskeletal conditions, as well as compare musculoskeletal conditions with other conditions by asking ‘how much disability is there in terms of DALYs?’ Patients with arthritis with can be compared to patients with cardiac disease, and so forth.

"The final piece of this equation, is to assign a dollar value to these DALYs, coming up with an overall economic burden for osteoarthritis or rheumatoid arthritis, cardiovascular diseases or tuberculosis," Shewan says.

The idea is to apply these measures as a baseline and then take measures at periodic points throughout the decade to measure any changes.

"Of course, with the health and economic indicators, a major issue is the need to come to a consensus about what measure we will use on a global basis," Shewan adds. "And we’ve been unable to do that. What works in the United States won’t necessarily work in Rowanda. But this was an extremely ambitious agenda for two days. We have more work to do–this is a big, big project."

The Bone and Joint Decade Monitor Project’s next steps will be decided at the upcoming working group meeting on Apr. 14-16 in Budapest, Hungary.

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