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-naïve 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-naïve patients, 58.2% of methotrexate non-responders, and 56% of remission patients were overweight or obese. However, 78.6% of treatment-naïve patients who were obese showed signs of likely follicular synovitis compared with 39.1% of patients in the same treatment-naïve 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.