To investigate the occurrence of extraarticular manifestations (ExRA) in a well defined community based cohort of patients with rheumatoid arthritis (RA), and to examine their effect on mortality.
Using the resources of the Rochester Epidemiology Project, a retrospective medical record review was conducted of a cohort of 424 cases of RA in Olmsted County, MN, USA, diagnosed during the period 1955-1985. These cases had been classified using the American College of Rheumatology 1987 criteria for RA. Patients were followed 1955-1998 (median followup 14.8 yrs; range 0.2-42.8 yrs), and incident ExRA manifestations were recorded according to predefined criteria. Data on comorbidities were extracted using the definitions of the Charlson comorbidity index. Survival was compared to the general population using Kaplan-Meier estimates.
ExRA occurred in 169 patients, corresponding to an incidence rate of 3.67/100 person-yrs. Compared to the general population, survival among patients with RA was decreased. Survival among patients with ExRA was markedly decreased compared to the general population and to patients without ExRA (p < 0.001). A particularly poor prognosis was noted in a subgroup of 63 patients (incidence rate 1.04/100 person-yrs) who fulfilled predefined criteria for severe ExRA (i.e., vasculitis, pericarditis, pleuritis, and/or Felty's syndrome). For RA patients who did not fulfill these criteria, there was no significant increase of mortality (p = 0.09). In a multivariate model of mortality, including age, sex, and the presence of known comorbidities, the presence of one or more of these ExRA was the strongest predictor of mortality.
In this first community based study of extraarticular manifestations in RA, virtually all the excess mortality occurred in a subgroup of patients with severe extraarticular disease, suggesting that extraarticular disease is the major predictor of mortality in patients with RA.