Excess mortality linked to rheumatoid factor positivity

The widening mortality gap between patients with rheumatoid arthritis (RA) and the general population is limited to those positive to rheumatoid factor (RF+) according to a recent population-based study. To investigate the influence of RF positivity on overall mortality trends and cause-specific mortality the researchers followed 603 RA patients (73% female, mean age 58 years) for an average of 16 years. A total of 398 patients died during follow-up, of whom 260 were RF positive. Overall mortality for these RF+ RA patients was significantly higher than that in the general population (standardised mortality ratio, SMR = 1.81). For the 138 RF negative patients the SMR was very similar to the general population at 0.99. "The difference between the observed and the expected mortality in the RF+ RA subjects increased over time, resulting in a widening of the mortality gap, while among RF— RA subjects, observed mortality was very similar to the expected mortality over the entire time period", the authors write. The report identifies that in RF+ patients cause-specific mortality was higher than expected for cardiovascular and respiratory diseases with no significant differences found between observed and expected cause-specific mortality in RF negative patients. The authors note that their findings imply different biological pathways for cardiovascular disease in RF+ patients that "may require different approaches to prevention and treatment." Reference...