Published 3/1/2003

Arthritis and related conditions

Arthritis and other rheumatic conditions, identified as AORC, are the second most common musculoskeletal diseases among adults and often lead to disability and the inability to work. Among the more recognized AORC conditions, which include more than 100 diseases, are osteoarthritis, a degenerative joint disease; rheumatoid arthritis, a chronic inflammatory condition; gout, a painful and recurrent form of arthritis recognized from ancient times; and lupus. More than 300,000 children are affected by rheumatic conditions.

In 2003-2005, 46.4 million persons, or 21.6 percent of the adult population, reported having an AORC condition. Women are more likely to suffer from osteoarthritis than men, but it affects both sexes. In 2005, symptomatic osteoarthritis in the hands was estimated to affect 13.1 mil­lion adults in the United States; 9.3 million adults had symptomatic knee osteoarthritis. Based on a doctor’s examination, an estimated 26.9 million adults had clinical osteoarthritis in at least one joint in 2005. Rheumatoid arthritis was estimated to affect 1.3 million adults in 2005.

The cost of arthritis and related conditions
In 2004, the estimated annual cost for medical care to treat all forms of arthritis and joint pain was $281.5 billion, an increase of 53 percent in 2004 dollars over the estimated cost in 1996. The increasing cost of prescription drugs accounts for the largest proportion of this increase, and now accounts for 23 percent of arthritis-related expenses.

Indirect cost of lost wages due to an arthritic condition was estimated to be $54.3 billion per year. About 9 percent of adults in the United States, nearly 19 million, reported they had limitations in performing activities of daily living due to an arthritic condition. This number is expected to grow to 25 million persons by the year 2030. In 2004, health care visits by persons with an AORC condition included 44.2 million ambulatory care visits, representing 5 percent of all care visits, to doctor’s offices, hospital emergency rooms, and outpatient clinics. As a primary, or first diagnosis, AORC conditions accounted for 992,100 hospitalizations, while 4.6 million patients were hospitalized with an AORC condition along with another condition. Osteoarthritis is the most frequent cause of health care visits for an AORC condition.

Impact of aging
One in two adults aged 65 and over has some form of arthritis. Osteo­arthritis and rheumatoid arthritis are both found in increasing frequency in an aging population. However, nearly two thirds of persons with arthritis are currently younger than 65 years. Although arthritis affects both men and women, it is more common in women.

Joint replacement: Treatment of choice for painful arthritic joints
Joint replacement has become the treatment of choice to restore function in severely arthritic joints. Arthroplasty procedures are available for a multitude of joints. The most frequently replaced joints are the knee and hip, followed by the shoulder. Total hip and primary knee replacements are performed almost exclusively due to osteoarthritis, with two of three persons hospitalized for osteoarthritis in 2004 undergoing a joint replacement procedure. A small proportion of replacements are due to rheumatoid arthritis or another condition. A partial hip replacement is performed principally for hip fracture. The number of joint replacement procedures performed each year has risen steadily since the early 1990s, with knee replacements showing the highest growth. In 2004, 1.07 million joint replacement procedures were performed (
Fig. 1).

Ninety-five percent of the procedures performed were on hips and knees. The estimated total hospital cost for joint replacements in 2004 was $30 billion. Joint replacement procedures are proven to be one of the most successful procedures available today. By 2030, it is projected more than 570,000 primary total hip replacements and nearly 3.5 million primary total knee replacements will be performed annually in the United States. Continued research to improve the longevity of implants is needed to reduce the overall burden and cost of arthritis-affected joints on an active, aging population.

The future
In recent years, new medications have been used to address pain and disability associated with arthritis and other rheumatic conditions. Ongoing testing and research is needed to ensure medications are both safe and effective.

Primary prevention of AORC remains a sought-after but elusive goal. Risk factors are not well understood for most of the conditions, and studies are needed to identify these before preventive measures can be developed. Early diagnosis and treatment that may prevent joint damage once the condition is present is a goal for those with rheumatoid arthritis and other inflammatory types of arthritis. Finally, the prevention of complications is being pursued through the use of medications and other recommended interventions, such as self-management of the disease, education, physical activity, and weight loss.

Arthritis is the most common cause of disability in adults, and a leading cause of work limitations. Over the next 25 years the number of people in the United States with arthritis and arthritis-attributable activity limitations is projected to increase by 40 percent to 67 million persons, affecting 25 percent of the adult population. Understanding the current and future impact of these conditions on the health care and public health systems is critical to reducing the burden of arthritis.

Editor’s Note: Each month AAOS Now will reprise a section of the Executive Summary prepared for The Burden of Musculoskeletal Diseases in the United States: Prevalence, Societal and Economic Cost. The text, which is available online at www.boneandjointburden.org, is a joint project of the AAOS, the American Academy of Physical Medicine and Rehabilitation, the American College of Rheumatology, the American Society for Bone and Mineral Research, the Arthritis Foundation, the National University of Health Sciences, the Orthopaedic Research Society, the Scoliosis Research Society, and the U.S. Bone and Joint Decade.


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