Complications and/or associated diseases in rheumatoid arthritis can present atypical clinical manifestations which may lead to an incorrect or delayed diagnosis. The aim of this study was to determine: (1) the complications of rheumatoid arthritis, the accompanying diseases, and the mortality of these, (2) the clinically missed diagnoses of complications and/or associated diseases, (3) the possible links between coexistent complications of rheumatoid arthritis and/or diseases associated with it, furthermore the possible role of these in the mortality of rheumatoid arthritis patients.
Between 1970 and 1999 10,860 patients died at the National Institute of Rheumatology, and among them 234 with rheumatoid arthritis (diagnosed clinically according to the criteria of the American College of Rheumatology). The associated and basic disease, complication(s), and causes of death were determined on the basis of clinical records and in each case the autopsy findings were confirmed by a review of extensive histological material (50-100 tissue blocks from each patient).
The complications of rheumatoid arthritis led to death in 152 (65%) of 234 patients. The complications of RA were clinically recognized in 109 (46.6%, 71.7 rel%) and missed in 43 (18.4% 28.3 rel%) of 152 patients. More than two thirds of lethal complications related to rheumatoid arthritis were diagnosed clinically. The remaining 82 (35%) of 234 rheumatoid arthritis patients died of associated diseases; the cause of death was clinically recognized in 78 (33.3%, 95.1 rel%) of 82 cases. There was a significant and positive correlation (1) between vasculitis and cardiac insufficiency (chi2 = 6.37, p <0.01), vasculitis and tuberculosis (chi2 = 4.18, p <0.04), or miliary tuberculosis (chi2 = 3.86, p <0.04); (2) between tuberculosis and miliary tuberculosis (chi2 = 54.84, p <0.001); and (3) between septic infection and purulent arthritis (chi2 = 97.04, p <0.001). There was a significant and inverse correlation between atherosclerosis and vasculitis (chi2 = 5.10, p <0.02), atherosclerosis and amyloidosis (chi2 = 14.58, p <0.001), or atherosclerosis and septic infection (chi2 = 3.81, p <0.05). There was a significant and inverse correlation between atherosclerosis and lethal cases of vasculitis (chi2 = 9.31, p <0.002), of amyloidosis (chi2 = 6.82, p <0.009), of sepsis (chi2 = 3.81, p <0.05) furthermore, between atherosclerosis with lethal outcome (n = 60 of 106) and vasculitis (chi2 = 12.06, p <0.001), or amyloidosis (chi2 = 13.22, p<0.002), or sepsis (chi2 = 10.82, p <0.001), or purulent arthritis (chi2 = 4.18, p <0.04).
The most important life threatening complications of rheumatoid arthritis (vasculitis, AA amyloidosis and sepsis) are present and lead to death with higher probability in the younger age group (without atherosclerosis), while in older patients who have atherosclerosis these represent a lower risk of death.