Prognostic value of serial neutrophil-to-lymphocyte ratio measurements in hospitalized community-acquired pneumonia

Abstract

Introduction Several serum inflammatory markers are associated with poor clinical outcomes in community-acquired pneumonia (CAP). However, the prognosis and early treatment response in hospitalized CAP patients based on serial neutrophil-to-lymphocyte ratio (NLR) measurement has never been investigated. Methods We performed a retrospective observational study for 175 consecutive patients hospitalized with CAP between February 2016 and February 2018. NLR, C-reactive protein (CRP) and procalcitonin levels were measured on admission day (D1) and on hospital day 4 (D4). The Pneumonia Severity Index (PSI) was also assessed on admission. The primary endpoint was all-cause death within 30 days after admission. The secondary endpoint was early treatment response such as intensive care unit (ICU) admission during hospitalization and clinical unstability on day 4. Results The 30-day mortality rate was 9.7%. In multivariate analysis, NLR D4 (OR: 1.11; 95% CI: 1.04–1.18; P = 0.003) and its incremental change (NLR D4/D1 >1) (OR: 7.10; 95% CI: 2.19–23.06; P = 0.001) were significant predictors of 30-day mortality. NLR D4 and its incremental change were significant predictors of ICU admission and clinical unstability on day 4 in multivariate analyses. Adding of incremental NLR change significantly improved the prognostic ability of the PSI. The additive value of incremental NLR change for the prognostic ability of the PSI was larger than that of incremental CRP change. Conclusion Serial NLR measurement represents useful laboratory tool to predict the prognosis and early treatment response of hospitalized CAP patients.

Neutrophil to Lymphocyte Ratio: An Emerging Marker of the Relationships between the Immune System and Diseases

“…It is characterized by high rates of mortality and morbidity, especially in elderly patients. NLR has demonstrated a strong predictive value concerning short- and long-term mortality, need for ICU admission and re-hospitalization [ 24 , 25 , 26 , 27 , 28 ]. Therefore, NLR correlated with post-CAP mortality better than traditional pneumonia scores (Pneumonia Severity Index, PSI; and Confusion, Urea, Respiratory rate and Blood pressure, aged 65 and older, CURB-65), WBC and CRP [ 24 ].…”

“…Furthermore, 3-month likelihood of rehospitalization increases in parallel with NLR increase, with a rate >75% when NLR is >20 [ 24 ]. Other authors have observed that not only NLR value but also its incremental change can predict clinical instability and all-cause 30-day mortality [ 26 ]. Of note, NLR values on admission did not differ significantly between survivors and non-survivors [ 26 ], while those at 3–5 days differed and predicted more accurately 30-day mortality [ 27 ].…”

“…Other authors have observed that not only NLR value but also its incremental change can predict clinical instability and all-cause 30-day mortality [ 26 ]. Of note, NLR values on admission did not differ significantly between survivors and non-survivors [ 26 ], while those at 3–5 days differed and predicted more accurately 30-day mortality [ 27 ]. This suggests that admission NLR values could not be used as a mortality prediction tool in hospitalized patients for CAP [ 26 ] or ventilator-acquired pneumonia (VAP) [ 28 ], due to the better performance of serial measurements.…”

“…Of note, NLR values on admission did not differ significantly between survivors and non-survivors [ 26 ], while those at 3–5 days differed and predicted more accurately 30-day mortality [ 27 ]. This suggests that admission NLR values could not be used as a mortality prediction tool in hospitalized patients for CAP [ 26 ] or ventilator-acquired pneumonia (VAP) [ 28 ], due to the better performance of serial measurements. Recently, in a post hoc analysis of a randomized clinical trial (RCT) investigating adjunctive dexamethasone treatment in CAP, patients with NLR ≥ 15.5 experienced benefit from dexamethasone treatment in terms of hospital stay shortening by 2 days [ 29 ].…”

Comparison of Different Scoring Systems for Prediction of Mortality and ICU Admission in Elderly CAP Population

“… 35 , 36 However, unfortunately, NLR was not statistically significant in the multivariable logistic model. In a recent study, Lee et al 37 found a significant association between the NLR value on day 4 with 30-day mortality and ICU admission whilst this value on day 1 was not associated significantly. NLR in our study was collected within 24 hours of admission.…”