Baseline and dynamic CALLY index changes predict mortality in sepsis-associated acute kidney injury: a two-center...

Sepsis-associated acute kidney injury (SA-AKI) is associated with high mortality rates, yet prognostic biomarkers that jointly reflect nutritional, inflammatory and immune status remain limited. This study aimed to assess the prognostic value of the C-reactive protein-albumin-lymphocyte (CALLY) index in this patient population.

In this retrospective two-center cohort study, 1,019 adult patients with SA-AKI were included. Kaplan-Meier and log-rank analyses identified the Day 3 CALLY index as the primary prognostic variable. Restricted cubic spline (RCS) analysis was used to characterize nonlinear associations with mortality, multivariable Cox proportional hazards models were applied to adjust for potential confounders, exploratory causal mediation analysis were performed to assess the contribution of the CALLY index to age-related mortality risk, and Bayesian joint models were used to evaluate the prognostic value of longitudinal CALLY trajectories.

A higher Day 3 CALLY index was independently correlated with lower 30-day mortality (HR: 0.997, 95% CI: 0.995-0.999) and showed similar associations with 60-day, 365-day, and in-hospital outcomes (all p < 0.05). RCS analysis revealed a significant L-shaped nonlinear association with the Day 3 CALLY index and 30-day mortality, with an inflection point of 11.52. Mediation analysis indicated that the CALLY index explained 23.8-28.7% of the association between age and mortality. In Bayesian joint models, the inverse association between the CALLY index and mortality became progressively stronger over time.

The CALLY index, an integrated marker of nutritional, inflammatory, and immune status, was independently associated with mortality in patients with SA-AKI. The Day 3 CALLY index provided clinically relevant prognostic stratification, and its longitudinal changes further improved risk assessment.