dNLR, NLR, and NMLR as differential markers for assessing severity and sepsis in emphysematous pyelonephritis

This study aims to evaluate the association between blood count-derived inflammatory markers and the severity of radiographic disease, as well as the presence of sepsis in patients with Emphysematous pyelonephritis.

This retrospective cohort study included 47 adult patients diagnosed with EPN. Anatomical severity was assessed using Huang's grading system based on admission CT scans. Sepsis diagnosis followed the Sepsis-3.0 criteria. CBC-derived indices were calculated from initial admission blood test results. Intergroup comparisons, effect size analysis, receiver operating characteristic curves, and correlation analyses were performed.

The derived neutrophil-to-lymphocyte ratio (dNLR) had a statistically significant association with Huang's CT classification (H = 9.555, p = 0.023), with median values increasing with severity grade. In sepsis, both NLR and NMLR levels were considerably higher (p = 0.041 and p = 0.033, respectively). NMLR had the largest effect size (r = 0.45) and the best discriminatory performance (AUC = 0.683, 95% CI: 0.520-0.846). Internal correlation analysis found that NLR and NMLR were highly correlated, while dNLR was weakly correlated with them, suggesting distinct dimensions of information. However, none CBC-derived inflammatory markers were related to long-term unfavorable outcomes (death or permanent dialysis), which were robustly predicted by traditional renal function markers (creatinine and cystatin C; all p < 0.05).

dNLR, NLR, and NMLR are readily obtainable CBC-derived indicators that show distinct clinical associations in EPN. dNLR correlates with anatomical disease severity, while NLR and NMLR are superior indicators for identifying concomitant sepsis. These inexpensive markers offer practical, complementary tools for acute-phase risk stratification, aiding in the timely recognition of severe disease and systemic complications.