Rheumatoid arthritis patients are at increased risk for adverse events following lumbar discectomy

Abstract

Background context: Lumbar discectomy is a common procedure for which patients with rheumatoid arthritis (RA) may be considered. RA is an autoinflammatory disease that may predispose patients to postoperative adverse outcomes.

Purpose: To assess the relative odds of adverse events after lumbar discectomy for those with versus without RA in a large, national, administrative dataset.

Study design/setting: Retrospective cohort study using the 2010 to 2020 MSpine PearlDiver dataset.

Patient sample: After exclusion of patients under 18 years old, those with any trauma, neoplasm, or infection diagnosis within the month before lumbar discectomy, and any patients who had any alternative lumbar spinal surgery performed on the same day as lumbar discectomy, we identified 36,479 lumbar discectomy patients. 2,937 (8.1%) of these patients had a prior diagnosis of RA. After matching 4:1 by patient age, sex, and Elixhauser Comorbidity Index (ECI, a longitudinal measure of patient comorbidity burden generated via ICD-9 and 10 diagnosis codes), 8,485 lumbar discectomy patients without RA and 2,149 with RA were included.

Outcome measures: Incidence of severe and minor adverse events in the 90-days following lumbar discectomy, predictive factors for adverse events within 90-days of lumbar discectomy, risk of adverse events within 90-days of lumbar discectomy stratified by patient medication regimen, 5-year survival to reoperation following lumbar discectomy.

Methods: Patients undergoing lumbar discectomy were identified from the PearlDiver MSpine dataset. The subset of those with versus without RA were identified and matched 1:4 based on patient age, sex, and ECI scores. The incidence of 90-day adverse events in the two groups was determined and compared by univariate and multivariate analyses. Subgroup analysis was performed based on RA medications being taken.

Results: Matched lumbar discectomy patients with RA (n=2,149) and without RA (n=8,485) were identified. Controlling for patient age, sex, and ECI, those with RA were at significantly higher odds of any (odds ratio [OR] 3.30), severe (OR 2.78), and minor (OR 3.30) adverse events (p<.0001 for all). Stratifying by medications being taken (and relative to those without RA), there was increasing odds of all adverse events (AAE) based on potency of medications (no biologic or disease modifying antirheumatic drugs [DMARDs] OR 2.33, DMARDs only OR 3.86, biologic±DMARDs OR 5.69 (p<.0001 for all). Despite this, no statistically significant difference in 5-year survival from subsequent lumbar surgery was found between those with versus without RA (p=.1000).

Conclusions: Lumbar discectomy patients with RA were found to be at significantly higher risk for 90-day adverse events following lumbar discectomy, and this was incrementally greater for those on increasingly suppressive medications. Lumbar discectomy patients with RA bear specific consideration and perioperative monitoring when considered for lumbar discectomy.

Keywords: Adverse events; Biologic medications; Lumbar discectomy; Outcomes; Rheumatoid arthritis; Spine.