Obesity May Lower Chances of Ridding RA

Obese rheumatoid arthritis patients taking TNF inhibitors had lower remission rates than nonobese patients

(RxWiki News) If you are obese, you are putting extra strain on your joints. That excess weight is known to make osteoarthritis worse. Could obesity also make it harder to treat rheumatoid arthritis?

Obese rheumatoid arthritis patients treated with anti-TNF medications had lower rates of remission (decrease or disappearance of symptoms) than patients who were not obese, according to a recent study.

"Control your weight to help manage rheumatoid arthritis."

Results also showed that different anti-TNF medications led to different outcomes. Researchers compared remission rates among patients taking three anti-TNF medications: Humira (adalimumab), Enbrel (etanercept) and Remicade (infliximab). Patients taking infliximab had the lowest remission rates. In fact, none of the obese arthritis patients treated with infliximab reached remission.

According to the authors, these findings suggest that obesity may be a roadblock to reaching remission. In addition, the best chance of putting rheumatoid arthritis into remission may be provided by etanercept and adalimumab.

Rheumatoid arthritis is an inflammatory joint disease, meaning it causes swelling and pain in the joints. Inflammation also plays a role in obesity.

Elisa Gremese, MD, of Catholic University of the Sacred Heart in Rome, Italy, and colleagues wanted to see if obesity reduced the chance of remission in patients with long-standing rheumatoid arthritis treated with anti-tumor necrosis factor (anti-TNF) medications.

The study included 641 patients taking anti-TNFs. Of these, 260 were taking adalimumab, 227 were taking etanercept and 154 were taking infliximab.

Participants were split into three groups based on body mass index (BMI) - a measure of body fat. The first group consisted of normal-weight patients (BMI less than 25). The second group consisted of overweight patients (BMI between 25 and 30), while the third group was made up of obese patients (BMI over 30).

To determine remission rates, the researchers used the Disease Activity Score in 28 joints (DAS28) - a measure of rheumatoid arthritis disease activity that counts the total number of tender or swollen joints out of a total of 28 joints. DAS28 scores range from 0 to 10. A DAS28 of less than 2.6 is considered remission, whereas a score of more than 5.1 is considered high disease activity.

Of all the participants in the study, 66 (10.3 percent) were obese.

After 12 months of anti-TNF treatment, only 15.2 percent of obese patients reached remission. In comparison, 30.4 percent of overweight patients and 32.9 percent of normal-weight patients reached remission.

Results also showed similar rates of remission among patients treated with etanercept or adalimumab. While 35.6 percent of those taking etanercept and 34.3 percent of those taking adalimumab reached remission, only 19.5 percent of patients taking infliximab reached remission.

None of the obese patients treated with infliximab reached remission. In comparison, 22.4 percent of non-obese patients treated with infliximab achieved remission.

While 14.8 percent of obese patients treated with adalimumab reached remission, 30.1 percent of non-obese patients taking adalimumab reached the same goal.

Of the patients treated with etanercept, 27.6 percent of obese patients versus 36.2 percent of non-obese patients achieved remission.

"Obesity represents a risk factor for a poor remission rate in patients with longstanding rheumatoid arthritis treated with anti-TNF agents," the authors concluded.

"A personalized treatment plan might be a possible solution."

The study was published December 27 in Arthritis Care & Research. Funding and disclosure information was not available.

Review Date: 
January 16, 2013