The Influence of Rheumatoid Arthritis on Higher Reoperation Rates over Time Following Lumbar Spinal Fusion—A Nationwide Cohort Study

This study aimed to compare the rates of reoperation over time following first lumbar fusion in rheumatoid arthritis (RA) patients and non-RA patients. This study was conducted using Korean Health Insurance Review and Assessment (HIRA) data. We identified the RA group as 2239 patients who underwent their first lumbar fusion with RA and the control group as 11,195 patients without RA. This reflects a ratio of 1:5, and the participants were matched by sex, age, and index surgery date. The index dates were between 2012 and 2013. When comparing the rate of patients undergoing reoperation, the adjusted HR was 1.31 (95% CI: 1.10–1.6) in the RA group (p = 0.002). In terms of the three time intervals, the values in the time frames of