Background: Rheumatoid arthritis (RA) is an inflammatory disease that leads to altered body composition. The loss of lean mass with a preservation or increase in fat mass has been termed rheumatoid cachexia (RC), to contrast with classic cachexia, which is characterized by severe weight loss. There are limited data on the prevalence and progression of cachexia in RA over time, as well as on associated factors. Our aim was to determine the prevalence of cachexia and to determine associations with potential factors.
Methods: This prospective cohort study recruited consecutively patients diagnosed with RA and followed for 1 year. The assessments were performed: clinical features, body composition, and physical function. RC and classic cachexia were assessed by several established diagnostic criteria. The pairwise Student's t test, Chi-square test, and GEE were performed (accepted at p ≤ 0.05).
Results: Of 90 patients recruited, 81 completed the study. Most patients were women (88.9%), and the mean age was 56.5 ± 7.3 years. At baseline, the median DAS28-CRP was 3.0 (IQR, 1.0-3.0), 13.3-30.0% of the included patients had RC, while none met criteria for classic cachexia. The prevalence of cachexia did not change after 12 months. Disease activity status and treatment with biologic disease-modifying antirheumatic drugs were significantly associated with changes on body composition and physical function (p < 0.05).
Conclusions: In this cohort, RC was common, while classic cachexia was absent. Disease activity and use of biologic therapies were associated with changes on body composition and physical function, underscoring the importance of aiming for remission when treating RA.
Keywords: Adiposity; Cachexia; Muscle; Rheumatoid arthritis; Rheumatoid cachexia.