By Linda Rath | Updated April 28, 2022
Being overweight can worsen rheumatoid arthritis (RA) symptoms, sets you up for other health problems and can make certain arthritis medications less effective. About two-thirds of people with RA are overweight or obese – the same proportion as in the general population. But when you have RA, extra body fat can create extra problems.
Why obesity matters
The fat in your body doesn’t just fill up. It is an active organ that releases hormones called adipokines. Some affect glucose metabolism; others play a role in your immune system and regulate your appetite. If you are a healthy weight, your fat cells produce mainly beneficial adipokines. But excess fat tissue releases high levels of cytokines—proteins that can cause inflammation throughout your body. These are the same proteins produced by joint tissue in RA. In addition to causing other health problems, cytokines make existing joint inflammation worse.
Disease progression
People who are obese have more pain and disability than their thinner counterparts. Yet they also have less inflammation and slower disease progression, as seen on imaging tests. Part of the problem may be a disconnect between findings on physical exam — such as swollen joints — and what shows up on an ultrasound or MRI. A physical examination may not be a very reliable way to determine disease activity and progression in people who carry extra weight.
Other health problems
Obesity doesn’t just make arthritis worse; it also causes other health problems. The same fat-related cytokines that attack your joints significantly increase your chances of developing type 2 diabetes and heart disease. Inflammatory cytokines make it harder for insulin to enter the cells. This causes glucose to build up in your blood and eventually leads to diabetes.
Inflammation also causes plaque to form more quickly in the arteries of people who have RA. This slowly narrows the blood vessels, blocking blood flow and is the main cause of heart attacks and strokes. People with RA already have a 50% higher risk of cardiovascular mortality than the general population, says Jon Giles, MD, associate professor of medicine, researcher and rheumatologist at Columbia University Medical Center. “You don’t want to have fat that increases your risk of heart disease,” he says.
Response to treatment
Some studies suggest that certain arthritis drugs, particularly tumor necrosis factor (TNF) blockers such as infliximab (Remicade) and adalimumab (Humira) drugs don’t work as well when people with RA are overweight. Other studies have found no difference in medication effectiveness based on weight. And a large study that used a decade’s worth of data from more than 23,000 veterans with RA reported that methotrexate and TNF blockers were less effective in underweight and normal-weight people than in those who were obese. Since there have been no direct comparisons of different medications in RA patients who are obese, there is no way to account for these different results. Still, some doctors may increase the dose of a drug like infliximab in obese patients. According to French researcher Eric Toussirot, MD, fat cells can bind to drugs like infliximab, rendering them dysfunctional.
Nevertheless, obese RA patients have worse outcomes, a greater risk of other chronic conditions, and a poorer quality of life than normal-weight patients.
