Incremental prognostic value of pan-immune-inflammation value in conservatively treated acute myocardial infarction: derivation and MIMIC-IV validation.

INTRODUCTION: Immune-inflammatory activation contributes to adverse outcomes after acute myocardial infarction (AMI). the study evaluated whether the pan-immune-inflammation value (PIV) was associated with 6-month all-cause mortality and provided prognostic information beyond conventional clinical predictors. METHODS: This retrospective two-cohort study included 2,008 conservatively treated patients with AMI in the derivation cohort and 2,679 patients with AMI from the Medical Information Mart for Intensive Care IV (MIMIC-IV) in an independent evaluation cohort. PIV was prespecified as the primary index, with the systemic inflammation response index (SIRI) and systemic immune-inflammation index (SII) assessed as complementary indices. Associations were examined using multivariable logistic regression. Incremental performance was assessed against a prespecified clinical model, with 1,000-resample bootstrap internal validation and Firth penalized logistic regression. Owing to differences in variable availability, MIMIC-IV analyses used a cohort-specific adjustment model. RESULTS: Within 6 months, 57 patients died in the derivation cohort and 773 died in MIMIC-IV. In the derivation cohort, each 1-standard-deviation increase in log-transformed PIV was independently associated with mortality (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.19-2.04; P = 0.001), with a similar Firth estimate (OR, 1.55; 95% CI, 1.19-2.01; P = 0.001). Adding PIV increased the area under the receiver operating characteristic curve from 0.844 to 0.854 (Δ = 0.010; P = 0.169); the corresponding optimism-corrected values were 0.813 and 0.823 (corrected Δ = 0.0106). SIRI and SII yielded supportive findings. In MIMIC-IV, PIV remained associated with 6-month mortality (OR, 1.20; 95% CI, 1.10-1.32; P < 0.001), while the area under the curve increased only from 0.770 to 0.775 after adding PIV. CONCLUSION: Higher PIV was independently associated with mortality after AMI across both cohorts, but its incremental discrimination beyond conventional clinical factors was modest and statistically nonsignificant. The MIMIC-IV findings support the reproducibility of the association rather than direct validation of an unchanged prediction model. PIV may therefore be considered a complementary marker rather than a stand-alone risk-stratification tool. Prospective multicenter studies are required before clinical implementation.