Repeatability of induced sputum measurements in moderate to severe asthma

Rossall, Matthew; Cadden, Paul; Molphy, Stephanie Dawn; Plumb, Jonathan; Singh, Dave

doi:10.1016/j.rmed.2014.08.004

Cited by 10 publications

(9 citation statements)

References 15 publications

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“…It is important to recognize a number of limitations of our study. Airway microbiology was assessed based on induced sputum, which, although shown to provide reproducible inflammatory cell levels in patients with moderate-to-severe asthma, 28,29 only provides an approximation of lower airway microbiology (in common with other lower airway sampling strategies). 30 It is also important to note that induced sputum levels of neutrophils and eosinophils can change frequently 31,32 and that the relationships between airway microbiology and inflammatory phenotype reported are cross-sectional.…”

Section: Discussionmentioning

confidence: 99%

Inflammatory phenotypes in patients with severe asthma are associated with distinct airway microbiology

Taylor

Leong

Choo

et al. 2018

Journal of Allergy and Clinical Immunology

254

264

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Section: Discussionmentioning

confidence: 99%

Inflammatory phenotypes in patients with severe asthma are associated with distinct airway microbiology

Taylor

Leong

Choo

et al. 2018

Journal of Allergy and Clinical Immunology

254

264

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“…Blood eosinophils were only measured during screening in ADEPT but published data suggest substantial variability even during a 24 h period [ 24 ] again raising the question as to whether eosinophilic asthma, defined by bEOS, is a stable phenotype. Fleming et al reported low reproducibility for sputum eosinophils in children [ 25 ] as did Rossall et al in adults with moderate to severe asthma [ 26 ]. In contrast Simpson et al found these measures to be stable in adults with stable asthma [ 27 ].…”

Section: Discussionmentioning

confidence: 99%

Longitudinal stability of asthma characteristics and biomarkers from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study

et al. 2016

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BackgroundAsthma is a biologically heterogeneous disease and development of novel therapeutics requires understanding of pathophysiologic phenotypes. There is uncertainty regarding the stability of clinical characteristics and biomarkers in asthma over time. This report presents the longitudinal stability over 12 months of clinical characteristics and clinically accessible biomarkers from ADEPT.MethodsMild, moderate, and severe asthma subjects were assessed at 5 visits over 12 months. Assessments included patient questionnaires, spirometry, bronchodilator reversibility, fractional exhaled nitric oxide (FENO), and biomarkers measured in induced sputum.ResultsMild (n = 52), moderate (n = 55), and severe (n = 51) asthma cohorts were enrolled from North America and Western Europe. For all clinical characteristics and biomarkers, group mean data showed no significant change from visit to visit. However, individual data showed considerable variability. FEV1/FVC ratio showed excellent reproducibility while pre-bronchodilator FEV1 and FVC were only moderately reproducible. Of note bronchodilator FEV1 reversibility showed low reproducibility, with the nonreversible phenotype much more reproducible than the reversible phenotype. The 7-item asthma control questionnaire (ACQ7) demonstrated moderate reproducibility for the combined asthma cohorts, but the uncontrolled asthma phenotype (ACQ7 > 1.5) was inconstant in mild and moderate asthma but stable in severe asthma. FENO demonstrated good reproducibility, with the FENO-low phenotype (FENO < 35 ppb) more stable than the FENO-high phenotype (FENO ≥ 35 ppb). Induced sputum inflammatory phenotypes showed marked variability across the 3 sputum samples taken over 6 months.ConclusionsThe ADEPT cohort showed group stability, individual stability in some parameters e.g. low FEV1/FVC ratio, and low FENO, but marked individual variability in other clinical characteristics and biomarkers e.g. type-2 biomarkers over 12 months. This variability is possibly related to seasonal variations in climate and allergen exposure, medication changes and acute exacerbations. The implications for patient selection strategies based on clinical biomarkers may be considerable.

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“…It is interesting that estimates of repeatability of sampling have wide limits of agreement, of the same magnitude as the mean levels of neutrophils observed. 4 The present paper from Elliot et al reframes an interesting ques-tion about the precise origin of the cells contained in induced sputum samples. It has been suggested, logically, that induced sputum reflects the cells present in the large airways, 5 and further that elevated neutrophils are associated with more severe asthma.…”

mentioning

confidence: 89%

‘To measure is to know’ (Lord Kelvin)

Ward

Uller

2014

Respirology

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Repeatability of induced sputum measurements in moderate to severe asthma

Abstract: Sputum neutrophil percentage has good reproducibility in patients with moderate to severe asthma.

Cited by 10 publications

References 15 publications

Inflammatory phenotypes in patients with severe asthma are associated with distinct airway microbiology

Inflammatory phenotypes in patients with severe asthma are associated with distinct airway microbiology

Longitudinal stability of asthma characteristics and biomarkers from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study

‘To measure is to know’ (Lord Kelvin)

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