PARIS — Obese patients with rheumatoid arthritis (RA) have higher levels of disease activity at baseline than nonobese patients, according to the results of a new study.
Therefore, they probably receive more aggressive treatment to target than nonobese patients, said lead author Christopher Sparks, MD, from the Institute of Ageing and Chronic Disease at the University of Liverpool in the United Kingdom.
This could explain the paradox that obese patients have less radiologic joint progression than nonobese patients, even though they generally have a worse prognosis, he added.
Dr. Sparks presented the results here at the European League Against Rheumatism (EULAR) Congress 2014.
In this cross-sectional study, data were obtained from the Meteor Foundation International RA database on 3534 patients. Of these, 1553 had early RA (a disease duration of less than 12 months), and 1981 had established RA.
Patients were categorized by body mass index (BMI): underweight (<18.5 kg/m2), normal weight (18.5 to 24.9 kg/m2), overweight (25.0 to 25.9 kg/m2), obese I (30.0 to 34.9 kg/m2), and obese II (≥35 kg/m2).
Underweight and obese II patients were at least twice as likely as normal-weight patients to have high disease activity — measured with the disease activity score in 28 joints (DAS28) — and obese I patients were 1.5 times as likely.
In addition, underweight, obese I, and obese II patients were more likely to have higher levels of disability than normal-weight patients.
Observations were similar for both early and established RA.
Much of the increase in disease activity was related to higher baseline levels of blood inflammation and to higher baseline levels of self-reported global health impairment, Dr. Sparks reported.
A possible explanation for the more severe RA in obese patients is that adipokines can increase systemic inflammation and make it more severe, he said.
The association between adipokines and systemic inflammation in underweight patients is less clear because of the small number of patients in this category. He explained that it is a chicken- and-egg situation: "Does sustained inflammation make them underweight, or are underweight patients more at risk for higher disease activity?"
Because this was a cross-sectional study, more longitudinal data are needed to understand the association between body composition and RA, he added.
Another Good Reason to Encourage Weight Loss
"Adipokines in the mesenchymal tissue and in fat cells promote inflammation that can exacerbate joint destruction," said Ulf Müller-Ladner, MD, chair of the Department of Rheumatology at the University of Giessen in Germany and chair of the EULAR scientific program.
"This is another good reason to encourage overweight and obese patients with RA to lose weight. The more obese you are, the worse the prognosis," he explained. "If you have less fat, that equals less inflammation and less joint destruction."
Dr. Sparks and Dr. Müller-Ladner have disclosed no relevant financial relationships.
European League Against Rheumatism (EULAR) Congress 2014: Abstract OP0196. Presented June 11, 2014.
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Cite this: More Disease Activity in Obese Rheumatoid Arthritis Patients - Medscape - Jun 14, 2014.