Clinical value of the systemic immune-inflammation index in patients with Crohn disease.
Level 4 - case-series / case-control
Retrospective case-control study with matched healthy controls.
PubMed 41790688 · doi:10.1097/MD.0000000000047955
What was done
A retrospective case-control study evaluated the systemic immune-inflammation index (SII = neutrophil × platelet / lymphocyte), platelet-to-lymphocyte ratio (PLR), and neutrophil-to-lymphocyte ratio (NLR) in 119 patients with Crohn disease (CD) and 121 age- and sex-matched healthy controls at a single center between 2014 and 2023. Endoscopic activity was measured via the CD Endoscopic Index of Severity (CDEIS) and Simple Endoscopic Score for CD (SES-CD). Multivariable linear regression and receiver operating characteristic (ROC) curves evaluated SII's association with and diagnostic utility for penetrating CD.
What was found
SII was significantly higher in CD patients than in healthy individuals (P < .05). Among CD patients, SII was higher in males versus females and in patients with low versus high body mass index (P < .05). SII, PLR, and NLR showed positive correlations with CDEIS (R = 0.298–0.370, P < .01) and SES-CD (R = 0.309–0.382, P < .01), numerically higher than CRP (CDEIS: R = 0.252, P = .009; SES-CD: R = 0.295, P = .002). Penetrating disease was independently associated with SII (beta = 0.455, t = 5.250, P < .001). For detecting penetrating CD, SII had an ROC area under the curve of 0.710, with a cutoff of 1745.85 yielding 0.615 sensitivity and 0.783 specificity.
Why it matters
SII is an inexpensive, routine laboratory marker that tracks endoscopic inflammation and may help identify penetrating disease phenotype in Crohn disease.
Limits
The study is a single-center retrospective case-control analysis with modest sample size (n = 119 cases). Correlations with endoscopic indices were weak to moderate (R ~ 0.30–0.38), and diagnostic performance for penetrating disease was fair (AUC 0.710) with low sensitivity (61.5%). The abstract does not state whether immunosuppressive medications affecting cell counts were adjusted for.
Cited by
- contradicts The systemic immune-inflammation index is calculated from neutrophil, lymphocyte, and platelet counts on a standard complete blood count, and a score above 2 indicates an inflammatory state.