Background: Rheumatoid Factors (RF) are antibodies directed against the Fc portion of IgG and are involved in clearance of immune complexes. While RF can develop in a wide range of conditions, higher RF levels indicate a greater risk for a severe disease course in Rheumatoid Arthritis (RA) patients including cardiovascular complications and premature death. We investigated whether RF also constitute a risk factor for these outcomes in the general population.
Methods: We included 2,323 participants (46% male, mean age 50 years) free of CVD at baseline in 1972. RF positivity was defined as a score of ≥2 by latex agglutination (scale 0-5). All outcomes during 42-year follow-up were obtained from state-wide registries. The predictive value of RF for coronary heart disease, all cardiovascular disease and all-cause mortality was estimated by adjusted hazard ratios (HR) from Cox regression models.
Results: After adjustment for standard risk factors, RF positivity was not predictive of future CHD (HR 1.05, p = 0.61), CVD (HR 1,04, p = 0.63) or mortality (HR 1.03, p = 0.70) in the full CVD-free cohort. In an interaction model, RF in 41 out of 355 participants with an RA history was not predictive of CHD (HR 0.92, p = 0.77) or CVD events (HR 1.15, p = 0.51), but there was a borderline significant association with overall mortality (HR 1.41, CI 0.97-2.04, p = 0.07).
Conclusions: RF detected by Latex agglutination do not independently predict future CHD, CVD or death in the general population. However, the presence of RF in the context of a history of RA is associated with a moderate, borderline significant increase in the long term adjusted risk for all-cause mortality.
Keywords: Cardiovascular disease; Mortality; Rheumatoid arthritis; Rheumatoid factors.