Renal disorders in rheumatoid arthritis.

Renal disorders are a frequent cause of death in patients with rheumatoid arthritis (RA), but are less apparent in living RA patients. In part, this may be because of insensitive screening methods. In this review, some of the relations among renal pathology, renal function, and antirheumatic therapy are clarified. A classification of renal disorders according to etiology is proposed. Two categories of disorders are distinguished: those related to RA and its complications, and those related to drug therapy. The disorders belonging to these categories are reviewed. Finally, a case is made for the existence of a third category, "RA nephropathy." It is hypothesized that this mild and nonspecific nephropathy is the result of cumulative minor insults caused by the disease and its therapy. The presence of such a "subclinical" nephropathy would explain the greater sensitivity of RA patients to other renal insults, and the high prevalence of renal failure at death.