RENAL BIOPSY FINDINGS AND CLINICOPATHOLOGICAL CORRELATIONS IN RHEUMATOID-ARTHRITIS

Objective. To evaluate renal biopsy findings and clinicopathologic cor relations in patients with rheumatoid arthritis (RA). Methods. Retrosp ective study of renal biopsy specimens from 110 RA patients in whom th e clinical renal disease was probably due to RA itself and/or to antir heumatic therapy. Results. The most common histopathologic finding was mesangial glomerulonephritis (GN) (n = 40), followed by amyloidosis ( n = 33), membranous GN (n = 19), focal proliferative GN (n = 4), minim al-change nephropathy (n = 3), and acute interstitial nephritis (n = 1 ). Amyloidosis was the most common finding in patients with the nephro tic syndrome. In patients with isolated proteinuria, amyloidosis, memb ranous GN, and mesangial GN were almost equally common. Although mesan gial GN was found in almost two-thirds of the RA patients with hematur ia (with or without proteinuria), there still remained a 1 in 5 chance that the biopsy would reveal membranous GN or amyloidosis. Membranous GN was closely related to gold or D-penicillamine therapies, whereas mesangial GN probably related to RA itself. Conclusion. The renal morp hologic lesion in RA patients with isolated proteinuria and those with hematuria cannot be accurately predicted on the basis of clinical sym ptoms and signs. Biopsy is thus useful in differential diagnosis, asse ssment of prognosis, and decision-making with regard to treatment.