Virtually all studies dealing with the occurrence of amyloidosis in subjects with rheumatoid arthritis (RA) have been based on selected series collected from university clinics. The purpose of the study was to obtain information on the true prevalence of amyloidosis and the role of amyloidosis as a cause of death.
The study included all 1666 subjects (480 men and 1186 women) who had died in 1989 and had been entitled under the national sickness insurance scheme to receive specially reimbursed medication for RA.
Amyloidosis was regarded as an immediate cause or an intervening antecedent cause of death in 64 cases (3.8%) and as a contributory cause of death in 33 cases (2%), corresponding to a prevalence of 5.8%. Amyloidosis had been diagnosed during life in 89 instances and was detected at autopsy in eight instances. Twenty-three (4.8%) of the subjects were men and 74 (6.2%) were women (P = 0.25). Compared with the remaining subjects in the study series, the lifespan of the subjects with amyloidosis was shortened by 7.7 yr.
The prevalence of amyloidosis was lower than apparent from most earlier studies. Monitoring information derived from the Finnish sickness insurance system is a useful way of following trends in the occurrence of amyloidosis complicating RA.