Real-world utility of platelet count, hemoglobin, and iron levels as predictors of clinical response to vedolizumab in patients with ulcerative colitis: a retrospective, single-center study in Poland

Vedolizumab is a humanized immunoglobulin G1 monoclonal antibody used to treat ulcerative colitis. Being bionaïve is a recognized factor associated with a favorable response to therapy. Studies have revealed a correlation between the baseline hemoglobin concentration and the clinical response. This study analyzed multiple laboratory parameters to assess their predictive value for the clinical response to vedolizumab induction therapy at the 14th week and for a sustained response at the 52nd week. Forty-nine patients (29 males, 20 females; aged 18–82 years) who were receiving 55 vedolizumab treatment courses at the Department of Gastroenterology, Medical University of Lodz, were retrospectively evaluated. Patients were grouped by prior biological therapy exposure and clinical response, defined as a decrease of ≥ 3 points in the Mayo score from baseline at weeks 14 and 52. Laboratory tests, including hemoglobin, mean corpuscular volume, hematocrit, white blood cell count, neutrophils, lymphocytes, monocytes, platelet count, C-reactive protein, albumin, serum iron, creatinine, alanine aminotransferase, and aspartate aminotransferase, were performed at baseline and at the end of the 52nd week. Among the 55 treatment courses, 15 (27.27%) were discontinued due to lack of clinical response. Baseline hemoglobin (p = 0.0132), mean corpuscular volume (p = 0.0025), serum iron (p = 0.0119), and platelet count (p = 0.0424) were significantly associated with the clinical response at the 14th week. Multivariable logistic regression revealed that hemoglobin, serum iron, and mean corpuscular volume were independent positive predictors of response, whereas a higher platelet count was negatively correlated with response. Threshold values with moderate predictive value and high sensitivity were identified for hemoglobin > 11 g/dL (AUC = 0.753), serum iron > 3.6 µmol/L (AUC = 0.758), and platelet count < 492 × 10³/µL (AUC = 0.708). The baseline mean corpuscular volume was significantly greater in patients who maintained a clinical response at the 52nd week (p = 0.0477), although it lacked sufficient specificity to predict response at the 14th week. Baseline hemoglobin, serum iron, and platelet counts may serve as useful biomarkers for predicting the clinical response to vedolizumab induction therapy in ulcerative colitis patients. Iron deficiency anemia may be associated with a reduced likelihood of response. No reliable predictors of long-term response were identified, indicating the need for further prospective studies.