Inflammatory bowel disease (IBD) frequently requires repeated endoscopic assessments to evaluate mucosal inflammation and guide treatment decisions. However, endoscopy is invasive, expensive, and not always readily available. The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) have emerged as potential blood-derived inflammatory markers, but their relationship with objective measures of disease activity remains uncertain. We aimed to evaluate the association of NLR and PLR with endoscopic activity in patients with IBD.

This retrospective study reviewed medical records of patients followed in our department from January 2020 to October 2025. Demographic data, endoscopic findings, and histology results were collected. Patients with confirmed IBD were included if they underwent endoscopy in our unit and blood count parameters (neutrophils, lymphocytes, platelets) available within two weeks of the procedure. Endoscopic activity was classified using the Mayo endoscopic score for ulcerative colitis (UC) and the Simple Endoscopic Score for Crohn’s Disease (CD) and histological activity as present or absent.  Comparisons between activity groups, correlation analyses, logistic regression, and ROC curve evaluation were performed to assess the association and predictive value of NLR and PLR for endoscopic and histologic disease activity. All analyses were conducted in RStudio.

A total of 104 patients met the inclusion criteria (mean age 47.6 years; 66 males; 38 females), including 42 with CD and 62 with UC. PLR demonstrated a statistically significant association with endoscopic disease activity (β₀ = –1.2774, β₁ = 0.0063). ROC analysis showed an AUC of 0.608, with an optimal threshold of 145.09 corresponding to a sensitivity of 64.44% and a specificity of 59.32%. PLR did not correlate with histological inflammation (p = 0.18).

NLR was significantly associated with histologic inflammation in a probit regression model (β₀ = –0.02707, β₁ = 0.23253, p = 0.041), with an AUC of 0.629 and an optimal cut-off of 2.7 (sensitivity 52%, specificity 80%). However, NLR did not correlate significantly with endoscopic disease activity (p = 0.10).

Deep remission (combined endoscopic and histologic remission) was not significantly associated with PLR (p = 0.467) or NLR (p = 0.149). No significant associations were found between PLR (p = 0.892) or NLR (p = 0.947) and residual histologic inflammation among patients in endoscopic remission.

PLR demonstrated a significant association with endoscopic disease activity, suggesting potential utility as a simple, accessible biomarker to support non-invasive assessment in IBD. In contrast, NLR was associated only with histologic inflammation and did not correlate with endoscopic findings.