Impact of therapeutic agents on serum leucine-rich alpha-2 glycoprotein for monitoring endoscopically remitted ulcerative colitis

Purpose Serum leucine-rich alpha-2 glycoprotein (LRG) levels are measured to monitor ulcerative colitis (UC); however, the impact of concomitant medications on LRG remains unclear. This exploratory study aimed to determine the effects of various agents on serum LRG levels. Methods We conducted a single-center, retrospective study using medical records at our hospital from October 1, 2020, to June 30, 2023. Patients who underwent lower gastrointestinal endoscopy within 1 year before or after LRG measurement and had confirmed mucosal healing were included. The effects of medication on LRG levels were assessed using multiple regression analysis following multiple imputations. The analyzed agents included 5-aminosalicylic acid (5-ASA), immunomodulators, corticosteroids, calcineurin inhibitors, Janus kinase inhibitors, vedolizumab, interleukin-23 receptor antagonists, and anti-TNF-α agents. Results A total of 214 patients (351 measurements) were included. The median LRG was 11.2 µg/ml. Among patients, 63.2 had a Mayo Endoscopic Subscore of 0, while 36.8% had a score of 1. The frequency of medication use was as follows: 5-ASA (88.9%), immunomodulators (13.1%), corticosteroids (2.6%), calcineurin inhibitors (0.9%), Janus kinase inhibitors (5.7%), vedolizumab (3.4%), interleukin-23 receptor antagonists (1.7%), and anti-TNF-α agents (7.4%). Corticosteroids, calcineurin inhibitors, Janus kinase inhibitors, and anti-TNF-α agents were negatively associated with LRG (β = -3.42, -10.4, -2.34, and − 3.01, respectively). Conversely, vedolizumab and interleukin-23 receptor antagonists were positively associated with LRG. (β = 1.83 and 4.69, respectively). Conclusion LRG levels are influenced by medications, even in patients with mucosal healing. These effects should be considered when using LRG to monitor UC.