Amyloidosis as a cause of death in patients with rheumatoid arthritis.

OBJECTIVE To study amyloidosis as a cause of death along with associated factors and frequency of pre-mortem diagnosis in patients with rheumatoid arthritis (RA) autopsied between 1952 and 1991. METHODS We studied causes of death in 369 consecutively autopsied RA and 370 autopsied non-RA patients of the same sex, age at death, and year of autopsy. In those RA patients who died from 1973 onwards, we were also able to analyse clinical data: pre-mortem diagnosis of amyloidosis, clinical features of RA, and treatment. RESULTS Based on autopsy, amyloidosis was determined as a cause of death in 9.5% of RA and in none of the non-RA patients (p<0.001). In our RA patients, we detected no trend in deaths from amyloidosis between 1952 and 1991. The RA patients dying of amyloidosis died younger than those dying of other causes (p=0.001). During the course of the disease, the RA patients with amyloidosis had: higher erythrocyte sedimentation rate (p=0.002), lower haemoglobin (p<0.001), more frequently proteinuria (p<0.001) and renal failure (p<0.001) than did the rest of the RA patients. Pre-mortem, amyloidosis was diagnosed by biopsy in 65% of the RA patients with amyloidosis as their cause of death. CONCLUSION Amyloidosis may be undetected during the course of RA. Thus, it should be actively searched for in the patients with long-lasting and active disease, especially, if they have proteinuria or renal failure.