Low pan-immune-inflammation value is associated with increased mortality in septic patients with immunocompromised status: a multicenter retrospective cohort study

BACKGROUND: Pan-immune-inflammation value (PIV) is a readily available biomarker reflecting systemic inflammatory and immune status. Although elevated PIV is generally associated with adverse outcomes, its prognostic significance in septic patients with immunocompromised status (ICS) remains unclear. OBJECTIVE: To investigate the association between PIV and mortality in septic patients with ICS. METHODS: Septic patients with ICS were identified from the MIMIC-IV database and stratified into low-, medium-, and high-PIV groups according to tertiles of baseline PIV levels. The primary outcome was in-hospital all-cause mortality, and secondary outcomes included 1-year all-cause mortality and invasive fungal infection (IFI) during ICU stay. Kaplan-Meier analysis, multivariable Cox regression, and logistic regression were used to assess the associations between PIV and clinical outcomes. Mediation analysis was performed to assess whether IFI might be involved in the association between PIV and mortality. An independent external cohort was used for validation. RESULTS: A total of 1,898 patients with ICS were included. Compared with the medium-PIV group, the low-PIV group had significantly higher in-hospital and 1-year mortality. After multivariable adjustment, low PIV, rather than high PIV, was independently associated with increased in-hospital mortality (HR = 1.42, 95% CI: 1.09-1.86, P = 0.010) and 1-year mortality (HR = 1.28, 95% CI: 1.06-1.53, P = 0.009). Low PIV was also associated with increased odds of IFI in the MIMIC-IV cohort (OR = 1.46, 95% CI: 1.01-2.13, P = 0.040). Mediation analysis suggested a possible involvement of IFI in the association between low PIV and mortality in the MIMIC-IV cohort. In the external validation cohort, the association between low PIV and mortality was consistent. CONCLUSION: In septic patients with ICS, low PIV, rather than high PIV, was independently associated with increased in-hospital and 1-year mortality. PIV may serve as a readily available biomarker for mortality risk stratification in this high-risk population.