Growing burden of arthritis in the U.S.

Arthritis is the most common cause of disability in the United States. Over the next 25 years as the Baby Boom generation continues to age, the toll of this disease will escalate.

To have a clear picture of the looming disease burden and its impact on our nation's health care and public health systems, estimating disease prevalence - the number of people affected by any form of arthritis - is critical.

The National Arthritis Data Workgroup was formed to provide a single source of national data on various rheumatic conditions. Supported by the National Institutes of Health, the Centers for Disease Control, the American College of Rheumatology, and the Arthritis Foundation, its epidemiology experts use the best studies available to determine disease prevalence, assess potential disease impact, and identify gaps in our understanding of disease rates, populations, and social implications. In the January 2008 issue of Arthritis & Rheumatism (http://www.interscience.wiley.com/journal/arthritis), the group presents its latest report on the troubling state of arthritis in America.

Based on analyses of population estimates from the Census Bureau, responses from national surveys, and findings from scores of community-based studies across the country, the National Arthritis Data Workgroup offers an unsettling snapshot of the 2005 (and future) burden of arthritis. Some key findings of the study include:

• Overall arthritis: More than 21 percent of U.S. adults - over 46 million people - have arthritis or other rheumatic condition diagnosed by a doctor. Nearly two-thirds of arthritis patients are younger than 65. More than 60 percent are women. Disease rates are similar for whites and African-Americans and higher than the rates for Hispanics. By 2030, the number of people with arthritis is projected to increase to nearly 67 million - an increase of 40 percent.
• Osteoarthritis (OA): Nearly 27 million Americans suffer from OA, the most common type of arthritis, an increase from the 21 million estimated in 1990. Rising with age, OA prevalence also affects the hands and knees of women more frequently than men and of African Americans more frequently than whites.
• Rheumatoid Arthritis (RA): This confounding and destructive inflammatory disease affects 1.3 million adults, down from the 1990 estimate of 2.1 million--in part due to more restrictive classification criteria but also because of a real drop in prevalence. Trends show that the average age of diagnosis has increased steadily over time, suggesting that RA is becoming a disease of older adults.
• Gout: In 2005 roughly 3 million Americans had gout in the previous 12 months, up from the estimate of 2.1 million in 1990. An inflammatory arthritis linked to elevated uric acid in the blood, gout tends to be most prevalent among older men and more prevalent in older African American males than in older white or Hispanic males.
• Juvenile Arthritis: Based on recent data from pediatric ambulatory care visits, an estimated 294,000 children between the ages of infancy and 17 are affected by arthritis or other rheumatic conditions.
• The report also includes 2005 prevalence estimates for fibromyalgia, spondylarthritides, systemic lupus erythematosus, systemic sclerosis, Sjögren's syndrome, carpal tunnel syndrome, polymyalgia rheumatic/giant cell arteritis, and back and neck pain.

“Measuring the prevalence of arthritis poses many challenges,” acknowledges National Arthritis Data Workgroup spokesperson and member, Dr. Charles G. Helmick. For starters, some conditions are episodic and others have no standard case definition. In addition, estimates for some rheumatic conditions rely on small or older studies with results that might not apply to the current U.S. population. However, this report calls attention to the high prevalence of arthritis nationwide and the growing burden on not only our health care and public health systems, but also on American industry and society.