194* Understanding the natural progression in FEV1 decline in patients with cystic fibrosis

Taylor-Robinson, D.; Whitehead, M.; Olesen, Hanne Vebert; Pressler, T.; Diderichsen, Finn; Smyth, RL; Diggle, P.

doi:10.1016/s1569-1993(11)60210-5

Cited by 38 publications

(67 citation statements)

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“…This z-score range is similar to a previous study in children reporting reproducibility for measurements made 12 months apart [20]. Furthermore, multiple studies demonstrate that the "signal" such as treatment differences, or changes related to worsening symptoms, from both of these lung function tests is much greater than the "noise" or biological variability and can be useful for tracking cystic fibrosis lung disease over time [1,3,[21][22][23][24]. The similar within-subject variability observed for LCI and FEV1 is in contrast to the lower between-subject variability observed for LCI compared to FEV1 in interventional studies [7,8,25].…”

Section: Discussionsupporting

confidence: 84%

Inter-test reproducibility of the lung clearance index measured by multiple breath washout

et al. 2017

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The lung clearance index (LCI) has strong intra-test repeatability; however, the inter-test reproducibility of the LCI is poorly defined.The aim of the present study was to define a physiologically meaningful change in LCI in preschool children, which discriminates changes associated with disease progression from biological variability.Repeated LCI measurements from a longitudinal cohort study of children with cystic fibrosis and age-matched controls were collected to define the inter-visit reproducibility of the LCI. Absolute change, the coefficient of variation, Bland-Altman limits of agreement, the coefficient of repeatability, intra-class correlation coefficient, and percentage changes were calculated.LCI measurements (n=505) from 71 healthy and 77 cystic fibrosis participants (aged 2.6-6 years) were analysed. LCI variability was proportional to its magnitude, such that reproducibility defined by absolute changes is biased. A physiologically relevant change for quarterly LCI measurements in health was defined as exceeding ±15%. In clinically stable cystic fibrosis participants, the threshold was higher (±25%); however, for measurements made 24 h apart, the threshold was similar to that observed in health (±17%).A percentage change in LCI greater than ±15% in preschool children can be considered physiologically relevant and greater than the biological variability of the test.

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Section: Discussionsupporting

confidence: 84%

Inter-test reproducibility of the lung clearance index measured by multiple breath washout

et al. 2017

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“…The 2-year observation period was chosen based on availability of clinical data after assessment of the last isolates phenotyped in this study, representing a proximal window of clinical relevance. Additionally, although pulmonary exacerbations have been associated with both short-and long-term morbidity and mortality (9,32,33), less is understood about the associations between rate of decline in lung function and long-term outcomes, such as mortality, in part because of complexities in model development (34). Our study found mucoidy to be the in vitro phenotype most significantly associated with risk of a subsequent pulmonary exacerbation regardless of infection stage.…”

Section: Discussionmentioning

confidence: 71%

Pseudomonas aeruginosa In VitroPhenotypes Distinguish Cystic Fibrosis Infection Stages and Outcomes

Mayer-Hamblett

Rosenfeld

Gibson

et al. 2014

Am J Respir Crit Care Med

110

101

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Rationale: Pseudomonas aeruginosa undergoes phenotypic changes during cystic fibrosis (CF) lung infection. Although mucoidy is traditionally associated with transition to chronic infection, we hypothesized that additional in vitro phenotypes correlate with this transition and contribute to disease.Objectives: To characterize the relationships between in vitro P. aeruginosa phenotypes, infection stage, and clinical outcomes.Methods: A total of 649 children with CF and newly identified P. aeruginosa were followed for a median 5.4 years during which a total of 2,594 P. aeruginosa isolates were collected. Twenty-six in vitro bacterial phenotypes were assessed among the isolates, including measures of motility, exoproduct production, colony morphology, growth, and metabolism.Measurements and Main Results: P. aeruginosa phenotypes present at the time of culture were associated with both stage of infection (new onset, intermittent, or chronic) and the primary clinical outcome, occurrence of a pulmonary exacerbation (PE) in the subsequent 2 years. Two in vitro P. aeruginosa phenotypes best distinguished infection stages: pyoverdine production (31% of new-onset cultures, 48% of intermittent, 69% of chronic) and reduced protease production (31%, 39%, and 65%, respectively). The best P. aeruginosa phenotypic predictors of subsequent occurrence of a PE were mucoidy (odds ratio, 1.75; 95% confidence interval, 1.19-2.57) and reduced twitching motility (odds ratio, 1.43; 95% confidence interval, 1.11-1.84). Conclusions:In this large epidemiologic study of CF P. aeruginosa adaptation, P. aeruginosa isolates exhibited two in vitro phenotypes that best distinguished early and later infection stages. Among the many phenotypes tested, mucoidy and reduced twitching best predicted subsequent PE. These phenotypes indicate potentially useful prognostic markers of transition to chronic infection and advancing lung disease.

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“…However, this decline is different in different population groups. [10,15,16] The median age of the patients colonised by PA (19.9 years) in this study is significantly older than in many European centres, but this age is not the age of first colonisation. [17,18] The high rate of PA colonisation in the study subjects (51.7%) is greater than in some international studies, [9] but is comparable to local SA studies.…”

Section: Discussionmentioning

confidence: 58%

“…However, this has not been a consistent finding in all studies, Amin et al [19] in Canada having found that PA was not responsible for a decline in lung function. In contrast, in a UK study by Taylor-Robinson et al, [16] PA infection was associated with a more rapid rate of lung function decline. Similar results, with pulmonary decline, were reported in the USA and the UK.…”

Section: Discussionmentioning

confidence: 76%

The impact of chronic pseudomonal infection on pulmonary function testing in individuals with cystic fibrosis in Pretoria, South Africa

et al. 2014

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Corresponding author: R J Green (robin.green@up.ac.za) Background. Colonisation of the airway by Pseudomonas spp. in cystic fibrosis has been reported to be an important determinant of decline in pulmonary function. Objective. To assess pulmonary function decline and the presence of bacterial colonisation in patients with cystic fibrosis (CF) attending a CF clinic in a developing country. Methods. A retrospective audit of patients attending the CF clinic at Steve Biko Academic Hospital, Pretoria, South Africa, was performed. The data included spirometric indices and organisms routinely cultured from airway secretions (Pseudomonas aeruginosa (PA) and Staphylococcus aureus (SA)).Results. There were 29 study subjects. Analysis of variance for ranks (after determining that baseline pulmonary function, age, gender and period of follow-up were not contributing to pulmonary function decline) revealed a median decline in forced expiratory volume in 1 second, forced vital capacity and forced expiratory flow over 25 -75% expiration of 12%, 6% and 3%, respectively, for individuals colonised by PA. There was no pulmonary function decline in individuals not colonised by PA, or in individuals colonised by SA. Conclusion. Pulmonary function decline in this South African centre is significantly influenced by chronic pseudomonal infection. Other influences on this phenomenon should be explored.

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194* Understanding the natural progression in FEV1 decline in patients with cystic fibrosis

Cited by 38 publications

References 0 publications

Inter-test reproducibility of the lung clearance index measured by multiple breath washout

Inter-test reproducibility of the lung clearance index measured by multiple breath washout

Pseudomonas aeruginosa In VitroPhenotypes Distinguish Cystic Fibrosis Infection Stages and Outcomes

The impact of chronic pseudomonal infection on pulmonary function testing in individuals with cystic fibrosis in Pretoria, South Africa

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