Diagnostic efficacy of pan-immune inflammation value for ulcerative colitis activity: a study based on...

Faecal calprotectin (FC) has limitations including inconvenient sampling and limited accessibility, while several blood markers derived from complete blood counts demonstrate suboptimal diagnostic performance in monitoring ulcerative colitis (UC) disease activity. There is an urgent need for superior noninvasive biomarkers. The pan-immune inflammation value (PIV), a novel composite index derived from complete blood counts, has shown prognostic value in malignancies but remains unexplored in UC activity assessment.

A retrospective analysis was conducted on 196 patients with UC (145 with active disease, 51 in remission), with 136 patients forming the FC subcohort. The PIV, systemic immune inflammation index (SII), systemic inflammation response index (SIRI), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and FC were compared using receiver operating characteristic curves. Sensitivity analyses and a diagnostic grey zone (defined as ± 15% around the optimal NLR and PLR cut-offs) were employed to assess robustness.

Patients with active UC demonstrated higher PIV, SII, SIRI, NLR, and PLR compared with those in remission. The area under the curve (AUC) for PIV was 0.731, outperforming other CBC-derived blood markers and showing numerically comparable performance with FC (AUC = 0.764, 95% confidence interval: 0.668-0.860), with no statistically significant difference between the two (P = 0.547). Within the diagnostic grey zone (± 15%) where NLR and PLR were inconclusive, PIV was the only haematological marker retaining statistical significance in the full cohort, albeit with only fair discriminatory ability (AUC = 0.664, 95% CI: 0.539-0.789; P = 0.010). The primary diagnostic performance findings remained robust after winsorization, propensity score matching, and bootstrap resampling validation.

PIV represents a promising low-cost, blood-derived biomarker for assessing UC activity. In clinical settings where FC is unavailable or stool sampling is not feasible, PIV may provide supplementary discriminative information. However, its role as a substitute for FC or as a tool to guide decision-making in diagnostically uncertain scenarios requires confirmation in prospective, externally validated studies before any clinical application.

Not applicable. This study is a retrospective observational study and does not report the results of a health care intervention.