Rheumatoid arthritis increases the risk of pleural empyema

Background - Rheumatoid arthritis (RA) can lead to various pulmonary manifestations. Evidence shows the possible association between RA and pleural empyema. Methods - We conducted a retrospective cohort study to investigate the risk of pleural empyema in patients with RA. The RA group (n = 29,061) included newly diagnosed adult patients between 2000 and 2012. The comparison group (n = 1,16,244) included individuals without RA at a 1:4 ratio of frequency matched by age, gender, and diagnosis year. The occurrence of pleural empyema was monitored until the end of 2013. Results - Patients with RA had a higher risk of developing pleural empyema than those without RA (23.6 vs 1.82 per 10,000 person-years, adjusted hazard ratio = 11.0, 95% confidence interval [CI] = 8.90-13.5). Furthermore, intensive care unit admission rates of pleural empyema were 37.7% in the RA group and 37.2% in the comparison group (adjusted odds ratio [OR] = 1.02, 95% CI = 0.66-1.57). The 30-day mortality rates of pleural empyema were 11.2% in the RA group and 10.9% in the comparison group (adjusted OR = 1.01, 95% CI = 0.51-1.88). Conclusion - Patients with RA are at a greater risk of developing pleural empyema than those without RA.