PREVALENCE OF LOW BODY-MASS IN RHEUMATOID-ARTHRITIS - ASSOCIATION WITH THE ACUTE-PHASE RESPONSE

Objective-To ascertain the prevalence of low body mass in a rheumatoid arthritis (RA) population and to explore a possible relation with the acute phase response. Methods-97 patients who fulfilled the American College Rheumatology (ACR) criteria for RA were recruited.Change in we ight from initial presentation was noted. Body mass index (BMI), upper arm fat and muscle areas were recorded together with fat free mass ca lculated from the waist measurement. Blood samples were taken for eryt hrocyte sedimentation rate (ESR), C reactive protein (CRP), and serum albumin. Results-13% of the RA group fell into the lowest 5th centile for BMI for the general population. The loss of body mass was greater for lean tissue than fat, with over 50% of the RA group falling into t he lowest 10th centile of a reference population for the upper arm mus cle area. Female patients who lost greater than 15% of their initial w eight had higher health assessment questionnaire (HAQ) results than th e rest of the group (p=0.020). In female patients there was a signific ant correlation between reduced fat free mass and the acute phase resp onse (ESR p=0.016 and CRP p=0.003). Conclusions-There is an increased prevalence of low body mass, greatest for lean tissue, in the RA popul ation. In the female group there was an inverse relation between the a cute phase response and fat free mass. Female patients with RA who los e a significant amount of weight are more disabled as assessed by HAQ.