Evidence map›Paper›PMID 31900184›Full record

SynthesisRespiratory research2020

Blood eosinophil count, a marker of inhaled corticosteroid effectiveness in preventing COPD exacerbations in post-hoc RCT and observational studies: systematic review and meta-analysis.

Timothy H Harries, Victoria Rowland, Christopher J Corrigan, Iain J Marshall, Lucy McDonnell, Vibhore Prasad, Peter Schofield, David Armstrong, Patrick White

Open access · goldAbstract readMeta-AnalysisSystematic Review
PubMed Full text at PMC Publisher
In one paragraph

Synthesis in Respiratory research, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 46 papers, 2 of them syntheses that pooled it.

0numbers the graph read from it
0cells of the map it votes in
46citing papers in PubMed, 2 pooled it
7.7field-weighted citation impact, top 2% of its field
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

46 citing papers in PubMed, 2 syntheses or guidelines pooled it, 91 citations in OpenAlex.

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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

9 authors at 1 institution in 1 country.

Timothy H HarriesDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK. timothy.harries@kcl.ac.uk.ORCID http://orcid.org/0000-0002-3891-9157
Victoria RowlandDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
Christopher J CorriganDepartment of Asthma Allergy & Respiratory Science, King's College London, London, UK.
Iain J MarshallDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
Lucy McDonnellDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
Vibhore PrasadDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
Peter SchofieldDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
David ArmstrongDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
Patrick WhiteDepartment of Public Health and Primary Care, School of Population Health & Environmental Sciences, King's College London, 3rd floor Addison House, Guys Campus, London, SE1 1UL, UK.
King's College London · GB

Funding

Department of Health DRF-2015-08-091Department of Health PB-PG-0214-33060Medical Research Council MR/N015185/1National Institute for Health Research DRF-2015-08-091
6 · The paper itself

Abstract

backgroundBlood eosinophil count has been proposed as a predictor of response to inhaled corticosteroid (ICS) in the prevention of acute exacerbations of COPD. An optimal threshold of blood eosinophil count for prescribing ICS has not been agreed. Doubt has been cast on the role by observational studies. The role of inhaled corticosteroids in this relationship, independent of long-acting bronchodilators, has not been examined.

methodsWe conducted a systematic review of post-hoc analyses of randomised controlled trials (RCTs) and observational studies examining three blood eosinophil thresholds and the independent role of ICS. Included studies were categorised by the form (relative or absolute count) and cut point of eosinophil threshold used. Thresholds assessed were relative eosinophil count of 2%, and absolute counts of 150 cells/μL and 300 cells/μL. Three meta-analyses of the effect of ICS use in post-hoc analyses of RCTs based on these counts were carried out. Initial analysis included all studies of ICS vs. any non-ICS regimen. Further analysis examined the effect of ICS, independent of the effect of long-acting bronchodilators.

resultsSixteen studies examined the association between blood eosinophil count and response of exacerbation risk to ICS, in COPD patients. Eleven studies (25,881 patients) were post-hoc analyses of RCTs. Five studies (109,704 patients) were retrospective observational studies. The independent effect of ICS on the reduction of exacerbation risk was 20% at ≥2% blood eosinophil threshold (RR, 0.80; 95% CI, 0.74-0.85), 35% at ≥150 cells/μL blood eosinophil threshold (RR, 0.65; 0.52-0.79), and 39% at ≥300 cells/μL blood eosinophil threshold (RR, 0.61; 0.44-0.78). No association was found in four out of five observational studies.

conclusionThis is the first systematic review to assess, in post-hoc analyses of RCTs, the independent effect of ICS in reducing the risk of COPD exacerbation across a range of blood eosinophil thresholds. Association between ICS prescription and reduced exacerbation risk at these thresholds was confirmed. The lack of association found in the observational studies questions the relevance of these observations to a "real world" COPD population. To clarify the clinical utility of this biomarker, the association should be tested in prospective effectiveness studies.

Indexed as

Administration, InhalationAdrenal Cortex HormonesDisease ProgressionEosinophilsHumansLeukocyte CountObservational Studies as TopicPulmonary Disease, Chronic ObstructiveRandomized Controlled Trials as TopicAdrenal Cortex HormonesEosinophilsInhaled corticosteroidsObservational studiesPulmonary disease, chronic obstructiveRandomised controlled trials

Identifiers

PMID31900184
PMCPMC6942335
OpenAlexW2998646242

What OpenQuestion holds

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LicenceCC BY
Read underepoch 390

Registered trials

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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.