Predictive Value of NLMR, PLR, and Ferritin in Relation to SOFA, APACHE II, and SAPS II in Sepsis Patients

Abstract

Sepsis, a critical topic in the medical field, remains one of the deadliest pathologies in intensive care units. It involves an overzealous immune system, with a hyperinflammatory phase that overlaps with a subsequent hypoinflammatory phase. 

To ease the burden on medical systems, this study aimed to assess the predictive value of clinical severity scores (Sequential Organ Failure Assessment (SOFA), Acute Physiology and Chronic Health Evaluation II (APACHE II) score, and the Simplified Acute Physiology Score II (SAPS II)) and inflammatory biomarkers (neutrophile-to-lymphocyte-to-monocyte ratio (NLMR), and platelet-to-lymphocyte ratio (PLR), carboxyhemoglobin (COHb) and ferritin) in predicting outcomes of critically ill intensive care unit (ICU) patients.

This prospective, observational study included 101critically ill patients, for whom we assessed the parameters on the first and fifth days after confirmation of either sepsis or septic shock in ICU, according to the Sepsis-3 Consensus.

Severity scores showed significant correlations on both day 1 and day 5 across all groups. APACHE II and SAPS II correlated with ferritin on day 5 in sepsis, septic shock, and non-survivors. The severity scores correlated with COHb on day 5 in survivors, and on day 1 in non-survivors. NLMR and PLR correlated consistently across groups, with additional associations between these ratios, ferritin, and COHb, particularly in non-survivors.

Regarding mortality, NLMR on day 1 showed only modest predictive value, which declined to non-significant by day 5. In contrast, the SOFA, APACHE II, and SAPS II scores demonstrated good discriminatory ability on both days, confirming their strong and reliable performance in predicting mortality.

The study shows that simple cellular ratios and severity scores correlate with ferritin, COHb, and each other, reflecting inflammation, oxidative stress, and organ dysfunction in sepsis. Because these markers are inexpensive and easy to monitor, they may enhance bedside risk stratification, though broader prospective studies are still required.