Because a recent cohort study showed that the adjusted hazard ratio for septic arthritis in patients treated with anti-TNF agents was 2.3 (95% confidence interval (CI) 1.2 to 4.4) and hazard estimates for the first year of follow-up were found to be increased in anti-TNF treatment [16], it is especially important to carefully monitor early RA patients given anti-TNF agents. Here, TNF is linked to bacterial arthritis.