Background It has been known that reactive (secondary, AA) amyloidosis (RAA) is a major complication of rheumatoid arthritis and amyloidosis is still a main cause of death in rheumatoid arthritis (RA) patients. Diagnosis of amyloidosis is based on Congo red staining of amyloid deposits in tissue biopsies. The safe and simple examination is abdominal fat aspiration biopsy (AFAB).
Objectives The aim of the study was to investigate the positive rate of amyloid deposits in AFAB samples and to clarify whether the presence of amyloid deposits is correlated with the clinical features of patients.
Methods AFAB was performed in patients with established diagnosis of RA referred to our department during the period from 1996 to 2001.
Results Among 103 patients (15 males, 88 females) marked amyloidosis deposits were found in 34 (33%) cases. The incidence of amyloidosis was more frequent in male than female patients (53% male vs 29% female). Raised levels of creatinine (>1,3 mg%) were found in 27% patients with amyloidosis and 3% without amyloidosis; proteinuria respectively in 35% with positive AFAB and 13% with negative AFAB results. There was no difference in both groups according to age, presence of rheumatoid factor, values of erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), bacteriuria, presence of erosions in hand and weight. It was found, that patients with proven amyloidosis in AFAB had longer duration of RA (15 years) than patients without amyloidosis (4,5 years). The patients without amyloidosis were more intensively treated with disease-modifying antirheumatic drugs (DMARDs) than patients with amyloidosis what was especially distinct in patients with duration of RA at least ten years; simultaneously time of corticosteroid treatment was longer in patients with amyloidosis.
Conclusion The observed frequency of amyloidosis was very high when compared with results from other countries. In our opinion the reason probably lies in fact that RA patients were treated only with corticosteroids instead of intensive use of DMARDs. In addition AFAB gives a possibility to find the early phase of amyloidosis before occurrence of overt clinical symptoms like proteinuria or renal insufficiency.