Major Finding: Odds ratios (OR), adjusted for age, gender, and smoking status, were 4.1 for DAS28 and 3.67 for ESR comparing the baseline values of very obese patients with the other BMI groups.
Data Source: Study of 216 patients with clinically diagnosed early rheumatoid arthritis, with symptom duration of less than 1 year.
Disclosures: Ms. Ling had no conflicts of interest.
BRIGHTON, ENGLAND – Very obese patients with early rheumatoid arthritis appear to have higher disease activity at presentation, according to recent data.
In a study of 216 individuals with early, clinically diagnosed rheumatoid arthritis (RA), those with a body mass index (BMI) of 35 kg/m
As a result, use of the DAS28 to guide clinical decision making could result in disease-modifying antirheumatic drug (DMARD) therapy being given early on, suggested Stephanie Ling, who presented the findings.
Ms. Ling, a fifth-year medical student at the University of Liverpool, England, noted that earlier, more aggressive treatment of obese RA patients might explain why some studies have suggested that obesity, somewhat paradoxically, is actually beneficial in some patients with RA.
Indeed, studies have linked obesity with reduced mortality (Arch. Intern. Med. 2005;165:1624-9; Ann. Rheum. Dis. 2010;69:i61-4) and protection against radiographic joint damage (Ann. Rheum. Dis. 2008;67:769-74), although high levels of adiponectin – secreted from the fat tissue – are associated with increased joint inflammation (Arthritis Rheum. 2009;61:1248-56).
“Physiologically, obesity is characterized by the expansion of white adipose tissue, which is not a benign tissue,” Ms. Ling explained. White adipose tissue secretes fatty acids, and its constituent cells, the adipocytes, also secrete proinflammatory proteins, or adipokines.
“Obesity can be thought of as a chronic inflammatory state,” said Ms. Ling, adding that studies also indicate that “obesity could have adverse effect on RA disease activity.”
In the current study, patients' baseline disease characteristics, including DAS28 scores, rheumatoid factor status, and anti-cyclic citrullinated protein antibody status, were assessed according to BMI at presentation. All patients had early RA diagnosed by a consultant rheumatologist and had symptoms lasting for less than 1 year. The mean age of participants was 57 years and 57% of the cohort was female.
Patients were grouped according to their BMI category, as defined by World Health Organization (WHO) criteria. One-third fulfilled criteria for obesity, with approximately 22% in the obese I category (BMI more than 30 kg/m
Results showed that obese II–III patients were more likely to present with elevated (5.1 or higher) DAS28 scores than their lighter counterparts. Odds ratios (OR) adjusted for age, gender, and smoking status were 4.1 for DAS28 and 3.67 for ESR when comparing the very obese patients with the other BMI groups.
Considering each component of the DAS28 separately, a high ESR (32 mm/h or more) was the main factor that appeared to be significantly higher as body weight increased. There was no association with tender or swollen joint counts, global visual analog scale, symptom duration, or rheumatoid factor/anti-cyclic citrullinated protein antibody status, Ms. Ling said.
“There is a need for well-designed longitudinal studies to examine the effect of obesity on the extent of RA disease progression,” she suggested.
Because obesity increases the erythrocyte sedimentation rate, overweight rheumatoid arthritis patients may have a higher disease activity score than their arthritis merits.
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