Related Experiment Videos
Biomarkers associated with post-operative pneumonia: a systematic review and meta-analysis
Fiona Howroyd1,2, Amanda Veiga Sardeli3, Fang Gao Smith3,4
1Department of Inflammation and Ageing, School of Infection, Inflammation and Immunology, College of Medicine and Health, University of Birmingham, Birmingham, UK. fjh722@student.bham.ac.uk.
Background:
Post-operative pneumonia is a commonly occurring surgical complication associated with poor patient outcomes. This study aimed to synthesise pre-operative and post-operative blood-based biomarkers associated with post-operative pneumonia.
Methods:
Electronic databases were searched up to April 14th, 2026. Primary studies investigating blood-based biomarkers in adults hospitalised after surgery were included. Meta-analysis was performed using the random effects model to compare pooled data for pneumonia and no-pneumonia groups using standardised mean difference. Risk of bias was assessed using the ROBINS-E tool.
Results:
Thirty-seven studies (n = 15,842 patients) were included, with an overall pneumonia rate of 17.8% [15.8-20.0%]. One hundred and fifteen biomarkers were identified. Meta-analysis identified that patients who developed post-operative pneumonia had significantly lower platelet-to-neutrophil ratio (p < 0.0001), red blood cell count (p = 0.001), haemoglobin (p = 0.002), albumin (p = 0.005) and lymphocyte count (p = 0.008) and significantly higher monocyte-to-lymphocyte ratio (p < 0.0001), systemic immune inflammation index (p < 0.001), systemic inflammatory response index (p < 0.0001) and blood urea nitrogen (p = 0.0001) at pre-operative baseline, compared to those without pneumonia. Patients who developed post-operative pneumonia were associated with significantly higher procalcitonin (PCT) at post-operative day one (p = 0.03), two (p = 0.0001), three (p = 0.0004) and six (p < 0.0001); higher C-Reactive Protein (CRP) at day two (p = 0.02), four (p < 0.0001) and five (p < 0.0001); higher interleukin (IL)-6 at day three (p = 0.001) and four (p = 0.0002); and higher white blood cell (WBC) count at day three (p = 0.01) and day four (p = 0.001) post-operatively, compared to those without pneumonia. In addition, pre-operative CRP was associated with mortality within the patients who later developed post-operative pneumonia (r = 0.70, p = 0.0009).
Conclusions:
The results identify blood-based biomarker signals associated with post-operative pneumonia. However, interpretation is limited by heterogeneous pneumonia definitions and inconsistent reporting of diagnosis timing across studies. The certainty of evidence is therefore limited, and thus these biomarkers cannot currently be used for prediction or diagnosis in clinical practice. Further high‑quality, prospective studies are required to establish clinically meaningful thresholds.
Protocol Registration:
PROSPERO: CRD42024570654.
Related Concept Videos
01:30Pneumonia III: Complications and Assessment
01:28Pneumonia IV: Management
Bacterial Pneumonia Treatment
For bacterial pneumonia, antibiotics serve as the cornerstone of therapy. Initial treatment often begins with empirical antibiotics, tailored to the anticipated causative organism and adjusted based on culture results. Key antibiotic choices include:
01:30Pneumonia I: Introduction
Risk Factors
Various factors influence the likelihood of developing pneumonia. Age plays a crucial role, with infants, children under two, and individuals over 65 at increased risk due to their...
01:29Pneumonia I: Introduction
01:30Pneumonia V: Nursing management and Prevention
The nurse must practice strict medical asepsis and adhere to infection control guidelines to minimize healthcare-associated infections.
Enhance airway patency
Position the patient correctly to facilitate drainage of the affected lung segments. Manual or mechanical percussion and vibration can also be employed.
01:29Pneumonia II: Pathophysiology