Contribution of rheumatoid arthritis disease activity and disability to rheumatoid cachexia

This cross-sectional study was done to show how nutritional indices influence each other and the contributions made by inflammation to the development of rheumatoid cachexia. We studied 295 female patients with rheumatoid arthritis (RA). We chose five nutritional indices: body mass index (BMI), arm muscle area (AMA), triceps skinfold thickness (TSF), which were obtained via anthropometric measurements, and serum albumin and cholesterol. Clinical indicators of RA included disease duration, C-reactive protein (CRP) and Disease Activity Score 28 (DAS28). We performed a bivariate correlation test between the nutritional indices and multiple regression analysis for each nutritional index. Mean AMA was low, 87.3% of the normal value, whereas TSF was not different. Muscle protein expressed by AMA decreased according to RA duration, whereas visceral protein indicated by serum albumin decreased with an increase in RA activity. The continuation of inflammation appears to be essential for a decrease in muscle protein in rheumatoid cachexia. DAS28 showed a positive contribution to BMI in the regression model, and the increase in RA disease activity causes an increase in BMI via an accumulation of tissue fat.