Obesity is associated with a higher degree of synovitis, lower remission, and higher disability, studies showed.
Excess weight is linked with a higher degree of synovitis in patients who have rheumatoid arthritis and can affect their treatment response, according to new research findings presented at the 2017 ACR/ARHP Annual Meeting, being held November 3-8 in San Diego.
In another study, rates of remission were lower and rates of disability were higher in patients with rheumatoid arthritis whose body mass index (BMI) scores were higher.
To learn more about the possible effects of excess weight on synovial tissue inflammation, a group of researchers in Italy studied a cohort of 125 patients with rheumatoid arthritis of various weights from disease onset to the achievement of stable remission.
“Obesity incidence is increasing in the general population, and multiple studies confirm that obesity is a risk factor associated with the development of RA,” said Stefano Alivernini, MD, a rheumatologist at Catholic University of the Sacred Heart in Rome and a lead author.
“We are interested in the analysis of fat-derived inflammation in systemic autoimmune diseases as RA, as well as the discovery of biomarkers to individualize and personalize treatment. Despite analysis of synovial inflammation in animal models of arthritis, no data are available on the synovial tissue analysis of such a population in humans.”
The study patients were divided into groups based on BMI: normal weight (BMI, under 25), overweight (BMI, 25 to 30) and obese (BMI, greater than 30). The researchers also performed immunohistochemistry on the patients for CD68+, CD21+, CD20+ and CD3+.
Each treatment-naÃ¯ve patient was treated according to the treat-to-target strategy and followed for 12 months.
Rates of overweight and obesity were comparable among 3 patient groups; 59.6% of DMARD-naÃ¯ve patients, 58.2% of methotrexate non-responders, and 56% of remission patients were overweight or obese. However, 78.6% of treatment-naÃ¯ve patients who were obese showed signs of likely follicular synovitis compared with 39.1% of patients in the same treatment-naÃ¯ve group who were of normal weight.
In addition, patients in this group who had a BMI greater than 35 kg/m2 showed higher histological scores for CD68+, sublining CD20+, CD21+ and sublining CD3+ cells than normal weight patients.
Patients who had not responded to methotrexate therapy showed similar degrees of synovial inflammation based on their BMI.
Patients whose disease was in stable remission showed lower disease activity index scores and inflammatory markers (erythrocyte sedimentation rate and C-reactive protein level) than treatment-naÃ¯ve patients. But overweight or obese patients in stable remission showed higher degrees of residual synovial inflammation compared with normal-weight patients with rheumatoid arthritis in remission.
The researchers concluded that overweight and obesity are associated with a higher degree of histologically proven synovitis in patients with rheumatoid arthritis from the time of disease onset to the achievement of stable remission and that this factor can influence the response rate to a T2T regimen.
“Based on these results, we believe that it’s important to track patients’ BMI in clinical practice, since there is a tight relation between the BMI category of RA patients and their chance of a good clinical response to treat-to-target,” said Dr Alivernini. “Since body weight is a modifiable factor, a standardized, multidisciplinary approach to help the patient achieve weight loss should be advised to increase disease control.”
Inflammation, Obesity, and Joint Dysfunction
In the second study, researchers in the United Kingdom wanted to more clearly define how inflammation, obesity, and joint dysfunction translate into clinical disease activity and functional disability in patients with rheumatoid arthritis. They explored associations between BMI and the achievement of disease remission or low disease activity and functional ability.
“Obesity is increasing in prevalence and represents a global health concern,” said Elena Nikiphorou, MD, a researcher in the Academic Rheumatology Department at King’s College, London, and a lead author. “It has been implicated as a risk factor for developing RA, and is an increasingly prevalent comorbidity seen on first presentation of RA.”
She added, “There is growing recognition that the inflammatory states mediated by obesity and those by inflammatory rheumatic diseases share common pathways. Some have suggested that in fact, obesity is a low-grade, chronic inflammatory condition. Thus, in RA co-existing with obesity, both autoimmune and obesity-mediated inflammatory states may work together, affecting disease activity and consequently important disease outcomes and quality of life.”
The researchers used data from 2 consecutive, multicenter rheumatoid arthritis inception cohorts with similar design.
In models that adjusted for age, sex, and year of recruitment, higher BMI was associated with reduced odds of the patients achieving Remission-DAS (R-DAS) and Low-DAS (L-DAS) scores. Higher BMI also predicted higher disability rates among these patients. Specifically, obesity increased a patient’s odds of higher disability by 63%, and higher DAS scores also strongly predicted higher disability.
“Our study’s findings demonstrate the increasing prevalence of obesity in RA patients and its negative consequences on disease activity, achieving a treat-to-target low disease activity goal and good functional outcomes,” said Dr Nikiphorou. “Obesity is potentially a reversible comorbidity and successfully treating it can contribute to better disease activity and functional outcomes. Based on our data, there is a strong argument to include obesity screening and management as a central part of all treatment plans for RA patients.”