The clinical significance of amyloid fat deposits in rheumatoid arthritis - A systematic long-term followup study using abdominal fat aspiration

Objective. To analyze the prevalence of subclinical amyloid fat deposits in patients with rheumatoid arthritis (RA) and to evaluate its clinical signi ficance. Methods. A cohort of 313 adult RA patients were included in this prospectiv e observational study. Systematic abdominal subcutaneous fat aspiration (AS FA) was performed on all patients at study entry. The prevalence of viscera l amyloidosis at study entry and at the end of followup was analyzed for pa tients with a positive ASFA test result. Followup ranged from 1 to 14 years (mean +/- SD 6.7 +/- 4.1 years). Patients with clinical and subclinical am yloidosis were compared with regard to clinical characteristics and the deg ree of amyloid deposits in abdominal fat. Results, The first ASFA test found amyloid in the abdominal fat of 51 patie nts (16.3%), and subsequent ASFA tests found amyloid in the abdominal fat o f 10 additional patients. At the time of the ASFA test, amyloidosis was sub clinical in 45 of these 61 patients, 41 of whom were followed up, During fo llowup, 11 of these 41 patients developed renal involvement, 5 due to amylo id nephropathy, Thus, amyloidosis remained subclinical in at least 30 of 41 patients (73%) throughout followup. Marked amyloid fat deposits were found more frequently in patients with clinical amyloidosis than in those whose amyloidosis remained subclinical at the end of followup (57% versus 22%; P = 0.04). Conclusion. Amyloid fat deposits are not uncommon in adult RA. In the major ity of patients, the deposits do not indicate clinically evident organic dy sfunction, even after several years of followup, Patients with more extensi ve fat deposits may have a higher risk of developing clinical amyloidosis.