Inflammatory Biomarkers and Disease Activity in Inflammatory Bowel Disease

Inflammatory bowel disease (IBD), encompassing Crohn's disease and ulcerative colitis, is a chronic relapsing condition requiring regular evaluation of disease activity to guide clinical decision-making and therapeutic management. While endoscopic assessment is the gold standard for mucosal evaluation, its routine application is limited by invasiveness, procedure risks, and high healthcare costs.

This cross-sectional study investigates the diagnostic accuracy and clinical utility of non-invasive, blood-based inflammatory ratios: C-reactive protein-to-albumin ratio (CAR), platelet-to-albumin ratio (PAR), neutrophil-to-lymphocyte ratio (NLR), fibrinogen-to-albumin ratio (FAR), and hemoglobin-to-C-reactive protein ratio (Hb/CRP).

Participants are recruited from the Clinical Pathology and Gastroenterology and Hepatology departments at Assiut University Hospital. Clinical disease activity is assessed using standardized clinical scores: the Mayo Clinic Score or Partial Mayo Score for ulcerative colitis, and the Crohn's Disease Activity Index (CDAI) or Harvey-Bradshaw Index (HBI) for Crohn's disease. In participants with available routine colonoscopy data within the study window, endoscopic disease activity is recorded using the Mayo Endoscopic Score (MES) or Ulcerative Colitis Endoscopic Index of Severity (UCEIS) for ulcerative colitis, and the Simple Endoscopic Score for Crohn's Disease (SES-CD) for Crohn's disease.

Venous blood samples are analyzed for complete blood count (CBC), serum albumin, C-reactive protein (CRP), and fibrinogen using automated laboratory analyzers (Advia and Atellica platforms) to calculate the corresponding inflammatory ratios and assess their discriminatory capacity.

Inclusion criteria

• Age 18 years or older
• Established diagnosis of Crohn's disease or ulcerative colitis
• Availability of adequate clinical information for disease activity assessment
• For the endoscopic subgroup: colonoscopy performed as part of routine clinical care within the study window with an available endoscopic report and corresponding disease activity score

Exclusion criteria

• Acute systemic infection at the time of assessment
• Active malignancy
• Other active systemic inflammatory or autoimmune diseases likely to significantly influence inflammatory biomarkers
• Significant hematological disease affecting hemoglobin, leukocyte, neutrophil, lymphocyte, or platelet counts
• Severe renal or hepatic dysfunction likely to substantially influence albumin or inflammatory markers
• Recent major surgery
• Pregnancy