As of the most recent global estimates, about 18 million people worldwide are living with rheumatoid arthritis (RA). That makes it one of the most common autoimmune diseases on the planet, affecting roughly 0.5% to 1% of the global population. The number is growing, and the disease hits certain groups far harder than others.
Global Numbers and Regional Differences
The World Health Organization put the worldwide count at 18 million in 2019, and the trend since then has been upward. Between 1990 and 2021, the global prevalence rate rose from about 183 to 209 per 100,000 people. Each year, somewhere between 25 and 50 new cases are diagnosed per 100,000 people.
Where you live plays a role in how common RA is. High-income countries carry the largest share of cases: in 2021, they accounted for roughly 36% of all prevalent cases worldwide despite representing a smaller fraction of the global population. Rates in Western Europe, high-income Asia Pacific, and Australasia are among the highest on record. At the other end, low-income and lower-middle-income regions currently have lower rates, but those numbers are climbing the fastest, with annual increases more than double those seen in wealthier countries.
Who Gets RA
Women develop rheumatoid arthritis about three times as often as men. The reasons aren’t fully understood, but hormonal differences and variations in immune system behavior between the sexes are thought to play a role. This 3-to-1 ratio holds up across most populations studied worldwide.
Most people first develop symptoms between the ages of 30 and 60. Cases that appear between 16 and 40 are sometimes called young-onset RA, while those diagnosed after 60 fall into the category of later-onset RA. The disease can technically start at any age, but that 30-to-60 window is the peak.
The Numbers Are Rising
RA is becoming more common, not less. The global incidence rate increased steadily from 1990 to 2021, growing at roughly 0.5% per year. Prevalence grew at a similar pace. One piece of good news: mortality rates for RA dropped by about 1.7% annually over the same period, likely reflecting better treatments and earlier diagnosis in many regions.
The growth in cases is particularly sharp in developing countries. Low-income and lower-middle-income regions saw incidence rates climb at more than 1% per year between 1990 and 2021. Meanwhile, some high-income regions, including Western Europe and high-income Asia Pacific, actually saw declines in the overall disease burden when adjusted for age, suggesting that better management is offsetting the rise in new cases.
Seropositive vs. Seronegative RA
Not everyone with RA has the same type. Doctors often split the disease into two broad categories based on blood test results. About 60% to 80% of people with RA test positive for specific antibodies (called anti-CCP antibodies or rheumatoid factor), which makes them “seropositive.” The remaining 20% to 40% test negative for these markers, a form known as seronegative RA.
This distinction matters because seropositive RA tends to be more aggressive. People with detectable antibodies are more likely to develop joint erosion and experience disease that progresses faster. Seronegative RA can still cause significant joint damage, but the course is often harder to predict and the diagnosis can take longer since standard blood tests don’t flag it as clearly.
The Financial Weight of RA
Rheumatoid arthritis is expensive to live with. In the United States, the average person with RA spent about $17,800 per year on healthcare in 2018, a figure that had jumped more than 37% over the previous decade. Out-of-pocket costs for prescription medications alone averaged $574 per year, with additional costs for office visits, emergency care, and hospital stays stacking on top.
Those numbers only capture direct medical spending. RA also drives significant productivity losses through missed workdays, reduced ability to perform physically demanding jobs, and in some cases, early disability. For many people, the financial impact of the disease is as burdensome as the physical symptoms.
How RA Is Identified in Population Studies
When researchers count how many people have RA, they rely on a standardized scoring system. A person needs to have visible joint swelling in at least one joint, with no other condition that better explains it. From there, doctors score four factors: how many joints are involved, whether blood tests show relevant antibodies, whether inflammation markers are elevated, and how long symptoms have lasted. A score of 6 out of 10 or higher qualifies as definite RA. This system, adopted in 2010, was designed to catch the disease earlier than previous criteria, which partly explains why modern prevalence estimates run higher than older ones.