Evidence map›Paper›PMID 42464235›Full record

SynthesisBMC pulmonary medicine2026

Biomarkers associated with post-operative pneumonia: a systematic review and meta-analysis.

Fiona Howroyd, Amanda Veiga Sardeli, Fang Gao Smith, Tonny Veenith, Niharika A Duggal, Zubair Ahmed

Abstract readSystematic ReviewMeta-Analysis
PubMed Publisher
In one paragraph

Synthesis in BMC pulmonary medicine, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

6 authors.

Fiona HowroydDepartment 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.ORCID http://orcid.org/0000-0002-2306-3376
Amanda Veiga SardeliDepartment of Inflammation and Ageing, School of Infection, Inflammation and Immunology, College of Medicine and Health, University of Birmingham, Birmingham, UK.ORCID http://orcid.org/0009-0005-7323-5956
Fang Gao SmithDepartment of Inflammation and Ageing, School of Infection, Inflammation and Immunology, College of Medicine and Health, University of Birmingham, Birmingham, UK.ORCID http://orcid.org/0000-0002-8095-0609
Tonny VeenithRoyal Wolverhampton Hospital, Wolverhampton, UK.ORCID http://orcid.org/0000-0002-4125-8804
Niharika A DuggalDepartment of Inflammation and Ageing, School of Infection, Inflammation and Immunology, College of Medicine and Health, University of Birmingham, Birmingham, UK.ORCID http://orcid.org/0000-0003-4459-4632
Zubair AhmedDepartment of Inflammation and Ageing, School of Infection, Inflammation and Immunology, College of Medicine and Health, University of Birmingham, Birmingham, UK. z.ahmed.1@bham.ac.uk.ORCID http://orcid.org/0000-0001-6267-6442

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

backgroundPost-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.

methodsElectronic 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.

resultsThirty-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).

conclusionsThe 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.

Indexed as

BiomarkersPneumoniaPostoperative ComplicationsC-Reactive ProteinHumansInterleukin-6ProcalcitoninBiomarkersC-Reactive ProteinInterleukin-6ProcalcitoninBiomarkersPneumoniaPulmonary complicationsRespiratory infectionSurgery

Identifiers

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.