Probability of treatment following acute decline in lung function in children with cystic fibrosis is related to baseline pulmonary function

Changing Epidemiology of Pediatric Pulmonary Exacerbations in Cystic Fibrosis

RATIONALE

The introduction of elexacaftor/tezacaftor/ivacaftor (ETI), a highly effective cystic fibrosis transmembrane conductance regulator (CFTR) modulator therapy, to younger ages and the COVID-19 pandemic have significantly reduced pulmonary exacerbations requiring hospitalization among children with CF.

OBJECTIVE

To assess demographic and clinical characteristics of children and young adults with CF hospitalized for pulmonary exacerbations before and after pediatric ETI approval.

METHODS

A retrospective chart review was conducted at five United States CF Foundation-accredited care centers. Hospitalization data from children and young adults with CF in 2018 and 2022 were analyzed.

RESULTS

Hospitalizations decreased from 471 cases (241 individuals) in 2018 to 163 cases (110 individuals) in 2022. The racial distribution shifted, with more hospitalized patients identifying as people of color in 2022 (28% vs. 14%; p = 0.018). A greater proportion of hospitalized children in 2022 had two non-F508del mutations compared with children hospitalized in 2018 (38% vs. 19%) and were less likely to be infected with methicillin-resistant Staphylococcus aureus (MRSA). Comparing 2022-2018, children on CFTR modulator therapy, including ETI (76%), showed reduced infections with Pseudomonas aeruginosa and Achromobacter xylosoxidans.

CONCLUSIONS

The decline in hospitalizations for pulmonary exacerbations likely reflects the benefits of ETI therapy, as a higher proportion of children and young adults hospitalized in 2022 had two non-F508del mutations and were not eligible for ETI. A greater percentage of those hospitalized in 2022 identified as belonging to minority racial groups, highlighting ongoing health disparities in the ETI era. Additionally, there were notable changes in the microbiological characteristics between 2018 and 2022.

Treatment of small as well as large declines in lung function enhances recovery to baseline in people with CF

BACKGROUND

The benefit of antibiotic treatment of acute drops in FEV1 percent predicted (FEV1pp) has been clearly established, but data from the early 2000s showed inconsistent treatment. Further, there is no empirical evidence for what magnitude of drop is clinically significant.

METHODS

We used data from the CF Foundation Patient Registry (CFFPR) from 2016 to 2019 to determine the association between treatment (any IV antibiotics, only oral or newly prescribed inhaled antibiotics, or no antibiotic therapy) following a decline of ≥5% from baseline FEV1pp and return to 100% baseline FEV1pp days using multivariable logistic regression including an interaction between the magnitude of decline and treatment category.

RESULTS

Overall, 16,495 PWCF had a decline: 16.5% were treated with IV antibiotics, 25.0% non-IV antibiotics, and 58.5% received no antibiotics. Antibiotic treatment was more likely for those with lower lung function, history of a positive PA culture, older age and larger FEV1 decline (p < 0.001). Treatment with IV antibiotics or oral/inhaled antibiotics was associated with a higher odds of recovery to baseline compared to no treatment across all levels of decline, including declines of 5%-10%.

CONCLUSIONS

A large proportion of acute drops in FEV1pp continue to be untreated, especially in younger patients and those with higher baseline lung function. Acute drops as small as 5% predicted are less likely to be recovered if antibiotic treatment is not prescribed. These findings suggest the need for more aggressive antimicrobial treatment of acute drops in FEV1, including those of a magnitude previously believed to be associated with self-recovery.

Improved recognition of lung function decline as signal of cystic fibrosis pulmonary exacerbation: a Cystic Fibrosis Learning Network Innovation Laboratory quality improvement initiative

INTRODUCTION

Cystic fibrosis (CF) is a systemic autosomal recessive condition characterised by progressive lung disease. CF pulmonary exacerbations (PEx) are episodes of worsening respiratory status, and frequent PEx are a risk factor for accelerated lung function decline, yet many people with CF (PwCF) go untreated at the time of decline. The goal of this quality improvement (QI) initiative was to improve recognition, treatment and follow-up of PEx in PwCF.

METHODS

Using the Model for Improvement, the Cystic Fibrosis Learning Network (CFLN) initiated a QI innovation laboratory (iLab) with a global aim to decrease the rate of lung function decline in PwCF. The iLab standardised definitions for signals of PEx using a threshold for decline in forced expiratory volume in one second (FEV1) and/or changes in symptoms. The FEV1 decline signal was termed FIES (FEV1-indicated exacerbation signal). Processes for screening and recognition of FIES and/or symptom changes, a treatment algorithm and follow-up in the presence of a signal were tested concurrently in multiple settings.

SPECIFIC AIMS

The specific aim is to increase the per cent of PwCF assessed for a PEx signal at ambulatory encounters and to increase the per cent of recommendations to follow-up within 6 weeks for PwCF experiencing a PEx signal.

RESULTS

FIES recognition increased from 18.6% to 73.4% across all teams during the iLab, and every team showed an improvement. Of PwCF assessed, 15.8% experienced an FIES event (>10% decline in FEV1 per cent predicted (FEV1pp)). Follow-up within 6 weeks was recommended for an average of 70.5% of those assessed for FIES and had an FEV1pp decline greater than 5%.

CONCLUSION

The CFLN iLab successfully defined and implemented a process to recognise and follow-up PEx signals. This process has the potential to be spread to the larger CF community. Further studies are needed to assess the impact of these processes on PwCF outcomes.

Social-environmental phenotypes of rapid cystic fibrosis lung disease progression in adolescents and young adults living in the United States

Background

Cystic fibrosis (CF) is a genetic disease but is greatly impacted by non-genetic (social/environmental and stochastic) influences. Some people with CF experience rapid decline, a precipitous drop in lung function relative to patient- and/or center-level norms. Those who experience rapid decline in early adulthood, compared to adolescence, typically exhibit less severe clinical disease but greater loss of lung function. The extent to which timing and degree of rapid decline are informed by social and environmental determinants of health (geomarkers) is unknown.

Methods

A longitudinal cohort study was performed (24,228 patients, aged 6-21 years) using the U.S. CF Foundation Patient Registry. Geomarkers at the ZIP Code Tabulation Area level measured air pollution/respiratory hazards, greenspace, crime, and socioeconomic deprivation. A composite score quantifying social-environmental adversity was created and used in covariate-adjusted functional principal component analysis, which was applied to cluster longitudinal lung function trajectories.

Results

Social-environmental phenotyping yielded three primary phenotypes that corresponded to early, middle, and late timing of peak decline in lung function over age. Geographic differences were related to distinct cultural and socioeconomic regions. Extent of peak decline, estimated as forced expiratory volume in 1 s of % predicted/year, ranged from 2.8 to 4.1 % predicted/year depending on social-environmental adversity. Middle decliners with increased social-environmental adversity experienced rapid decline 14.2 months earlier than their counterparts with lower social-environmental adversity, while timing was similar within other phenotypes. Early and middle decliners experienced mortality peaks during early adolescence and adulthood, respectively.

Conclusion

While early decliners had the most severe CF lung disease, middle and late decliners lost more lung function. Higher social-environmental adversity associated with increased risk of rapid decline and mortality during young adulthood among middle decliners. This sub-phenotype may benefit from enhanced lung-function monitoring and personalized secondary environmental health interventions to mitigate chemical and non-chemical stressors.

Breath of fresh insight: unraveling the evolution of our understanding of cystic fibrosis pulmonary exacerbations

PURPOSE OF REVIEW

Pulmonary exacerbations are critical events with significant negative impacts in persons with cystic fibrosis, but their diagnosis and management are highly variable. Highly effective modulator therapies have greatly improved health and reduced exacerbation events, but have also reshaped how they present. This review discusses the complexities of the diagnosis and management of pulmonary exacerbations as well as the emerging work and evidence in this area.

RECENT FINDINGS

The shifting epidemiology and our understanding of risk factors for pulmonary exacerbations are discussed. As symptoms may be more subtle in the modulator context, novel technologies including studies of remote monitoring are presented. The continued relevance of pulmonary exacerbations, the heterogeneity in their management, as well as current and forthcoming clinical trials to optimize treatment approaches are detailed.

SUMMARY

In spite of the dramatic reductions in pulmonary exacerbations, airway infections persist, a proportion of persons with cystic fibrosis either on or off modulator therapies continue to experience exacerbation events, and long-term data is lacking. Innovative approaches and studies will be crucial to enable standardized and generalizable strategies to improve outcomes in persons with cystic fibrosis.

Evaluating FEV1 decline in diagnosis and management of pulmonary exacerbations in children with cystic fibrosis

RATIONALE

Forced expiratory volume in 1 s (FEV1) decline (ΔFEV1) is associated with pulmonary exacerbation (PEx) diagnosis in cystic fibrosis (CF). Spirometry may not be available during telehealth visits and could impair clinician ability to diagnose PEx. This study aims to (1) identify the associations between degrees of ΔFEV1 (decrease of <5% predicted vs. 5%-9% predicted vs. ≥10% predicted from baseline), clinical symptoms, and clinician-diagnosed PEx and (2) evaluate the correlation between respiratory symptoms, ΔFEV1, and antibiotic treatment.

METHODS

Retrospective, descriptive study of PEx diagnosis and management in 628 outpatient clinical encounters with spirometry in 178 patients with CF ages 6-17 years at Riley Hospital for Children during 2019. Odds ratios (OR) of symptoms associated with clinician-defined PEx diagnosis and antibiotic management stratified by ΔFEV1 decline were determined.

RESULTS

Clinician-diagnosed PEx occurred at 199 (31.7%) visits; increased cough (77.4%) and sputum/wet cough (57.8%) were the most frequently reported symptoms. Compared to no ΔFEV1, the odds of a clinician-diagnosed PEx were increased when ΔFEV1_5%-9% and ΔFEV1_≥10% was present with increased cough (OR 1.56, 95% confidence interval [CI] 1.25-1.94 and OR 1.82, 95% CI 1.52-2.19, respectively), increased sputum (OR 1.59, 95% CI 1.20-2.12 and OR 1.78, 95% CI 1.37-2.32, respectively), and increased cough and sputum together (OR 1.51, 95% CI 1.08-2.13 and OR 1.68, 95% CI 1.22-2.31, respectively).

CONCLUSIONS

ΔFEV1 is associated with increased likelihood that cough and sputum are diagnosed as a PEx. Spirometry is essential for PEx diagnosis and treatment and is a necessary component of all clinical encounters.

Routine spirometry in cystic fibrosis patients: impact on pulmonary exacerbation diagnosis and FEV1 decline

OBJECTIVE

Pulmonary disease in cystic fibrosis (CF) is characterised by recurrent episodes of pulmonary exacerbations (PExs), with acute and long-term declines in lung function (FEV1). The study sought to determine whether routine spirometry increases the frequency of PEx diagnosis, resulting in benefits to long-term pulmonary function.

METHODS

CF patients in the 5- to 18-year age bracket were followed for 1 year, during which they underwent spirometry before every medical visit. The main variables were the frequency of PEx diagnosis and use of antibiotics; the use of spirometry as a criterion for PEx diagnosis (a decline ≥ 10% in baseline FEV1); and median percent predicted FEV1 over time. The data were compared with those for the previous 24-month period, when spirometry was performed electively every 6 months.

RESULTS

The study included 80 CF patients. PExs were diagnosed in 27.5% of the visits, with a mean frequency of 1.44 PExs per patient/year in 2014 vs. 0.88 PExs per patient/year in 2012 (p = 0.0001) and 1.15 PExs per patient/year in 2013 (p = 0.05). FEV1 was used as a diagnostic feature in 83.5% of PExs. In 21.9% of PExs, the decision to initiate antibiotics was solely based on an acute decline in FEV1. The median percent predicted FEV1 during the follow-up year was 85.7%, being 78.5% in 2013 and 76.8% in 2012 (p > 0.05). The median percent predicted FEV1 remained above 80% during the two years after the study.

CONCLUSIONS

Routine spirometry is associated with higher rates of diagnosis and treatment of PExs, possibly impacting long-term pulmonary function.

The Presence of Exophiala dermatitidis in the Respiratory Tract of Cystic Fibrosis Patients Accelerates Lung Function Decline: A Retrospective Review of Lung Function

Exophiala dermatitidis is increasingly isolated from cystic fibrosis (CF) respiratory samples. The decision to treat is hampered by limited evidence demonstrating the clinical significance of isolating E. dermatitidis. The objective was to assess the impact of E. dermatitidis isolation on the lung function of CF patients. The rate of lung function decline in the local CF population was calculated using historic lung function data. A control population who had never had E. dermatitidis cultured from the respiratory tract was compared with the E. dermatitidis group, calculating their rate of lung function decline before and after the first isolation of the organism. A total of 1840 lung function measurements were reviewed between the 31 E. dermatitidis group patients and 62 control patients. Their demographics were similar. The control group declined at a rate of −0.824 FEV1%/year. The rate of decline in the E. dermatitidis group prior to infection was −0.337 FEV1%/year (p = 0.2). However, post infection with E. dermatitidis, there was a significant increase in the rate of decline in lung function (−1.824 FEV1%/year, p < 0.01). The results suggest E. dermatitidis has a temporal relationship with accelerated rate of lung function decline. It is not clear if this is a cause or effect, but this accelerated rate of decline indicates a need for further investigation.

Factors in childhood associated with lung function decline to adolescence in cystic fibrosis

BACKGROUND

Despite improvements in general health and life expectancy in people with cystic fibrosis (CF), lung function decline continues unabated during adolescence and early adult life.

METHODS

We examined factors present at age 5-years that predicted lung function decline from childhood to adolescence in a longitudinal study of Australasian children with CF followed from 1999 to 2017.

RESULTS

Lung function trajectories were calculated for 119 children with CF from childhood (median 5.0 [25%-75%=5.0-5.1]) years) to early adolescence (median 12.5 [25%-75%=11.4-13.8] years). Lung function fell progressively, with mean (standard deviation) annual change -0.105 (0.049) for forced vital capacity (FVC) Z-score (p<0.001), -0.135 (0.048) for forced expiratory volume in 1-second (FEV₁) Z-score (p<0.001), -1.277 (0.221) for FEV₁/FVC% (p<0.001), and -0.136 (0.052) for forced expiratory flow between 25% and 75% of FVC Z-score (p<0.001). Factors present in childhood predicting lung function decline to adolescence, in multivariable analyses, were hospitalisation for respiratory exacerbations in the first 5-years of life (FEV₁/FVC p = 0.001, FEF_25-75p = 0.01) and bronchoalveolar lavage neutrophil elastase activity (FEV₁/FVC% p = 0.001, FEV₁p = 0.05, FEF_25-75p = 0.02). No examined factor predicted a decline in the FVC Z-score.

CONCLUSIONS

Action in the first 5-years of life to prevent and/or treat respiratory exacerbations and counteract neutrophilic inflammation in the lower airways may reduce lung function decline in children with CF, and these should be targets of future research.

Bayesian regularization for a nonstationary Gaussian linear mixed effects model

In omics experiments, estimation and variable selection can involve thousands of proteins/genes observed from a relatively small number of subjects. Many regression regularization procedures have been developed for estimation and variable selection in such high-dimensional problems. However, approaches have predominantly focused on linear regression models that ignore correlation arising from long sequences of repeated measurements on the outcome. Our work is motivated by the need to identify proteomic biomarkers that improve the prediction of rapid lung-function decline for individuals with cystic fibrosis (CF) lung disease. We extend four Bayesian penalized regression approaches for a Gaussian linear mixed effects model with nonstationary covariance structure to account for the complicated structure of longitudinal lung function data while simultaneously estimating unknown parameters and selecting important protein isoforms to improve predictive performance. Different types of shrinkage priors are evaluated to induce variable selection in a fully Bayesian framework. The approaches are studied with simulations. We apply the proposed method to real proteomics and lung-function outcome data from our motivating CF study, identifying a set of relevant clinical/demographic predictors and a proteomic biomarker for rapid decline of lung function. We also illustrate the methods on CD4 yeast cell-cycle genomic data, confirming that the proposed method identifies transcription factors that have been highlighted in the literature for their importance as cell cycle transcription factors.

The improved clinical course of persistent tachypnea of infancy with inhaled bronchodilators and corticosteroids

BACKGROUND

Persistent tachypnea of infancy (PTI) is the most common interstitial lung disease in young children. As no standardized therapeutic guidelines exist, different pharmaceuticals are used to treat PTI; inhaled corticosteroids (ICS) and bronchodilators being mostly used. This observation assessed the effectiveness of bronchodilators and ICS in children with PTI enrolled in the children's interstitial lung diseases (chILD)-EU Register.

METHODS

Symptomatic children with PTI were observed according to a predetermined stepwise protocol including bronchodilators as the first choice treatment (6 weeks). In patients with incomplete response, additionally, ICS was given (12 weeks). Signs, symptoms, and pulmonary function were evaluated at three time points: at baseline, 6 (±1) weeks after initiation of bronchodilators, and 12 (±1) weeks after bronchodilators/ICS.

RESULTS

Thirty-one children (median age: 44 months, interquartile range [IQR]: 15-67) were included. The therapy was associated with a significant reduction of tachypnea (53.3% of patients, p = 0.02), exercise intolerance (52.2% of patients, p < 0.001), chest retractions (43.8% of patients, p = 0.04), and crackles (29.2% of patients, p = 0.02). Also, a significant improvement in forced expiratory volume in 1 s (FEV₁ ) (median z score: -2.21 vs. -0.47, p = 0.03), residual volume (RV) (median z score 5.28 vs. 1.07, p = 0.007), RV% total lung capacity (TLC) (median z score: 6.05 vs. 1.48, p = 0.01), sRaw (median z score: 6.6 vs. 4.64, p = 0.01), R5 (median z score: 1.27 vs. 0.31, p = 0.009), and R5-R20 (median: 0.58 vs. 0.26 kPa/(l/s), p = 0.002) was demonstrated.

CONCLUSIONS

Inhaled bronchodilators and ICS may exert a positive effect on the severity of symptoms and pulmonary function test (PFT) in symptomatic children with PTI. However, a randomized control trial should be conducted to confirm their effectiveness.

Improving lung function in adolescents with CF by tracking annual rate of lung function decline

BACKGROUND

For patients with cystic fibrosis (CF), sustaining lung function through the adolescent years is crucial to slow the progressive decline that leads to significant morbidity and early mortality. This holds true for patients with high per cent predicted forced expiratory volume in 1 s (ppFEV₁), as they may receive less vigilant monitoring and treatment. Early identification of lung function decline followed by aggressive treatment can lead to preservation of lung function.

INTERVENTION

The Emory+Children's Pediatric Cystic Fibrosis Program implemented multiple quality improvement (QI) initiatives to identify and aggressively treat adolescent patients with a rapid decline in lung function. These initiatives included (1) lung zones to categorise and highlight lung function decline, (2) individual lung decline tables for quick reference, (3) a lung health algorithm to encourage uniformity, (4) a rapid decliner checklist to identify potential reasons for individual decline and (5) an automated individual patient-level data report and centre scorecard. We tested these interventions with plan-do-study-act cycles and refined as needed.

RESULTS

Implementation of these QI initiatives resulted in overall improvement in lung function and slowing of lung function decline among adolescents with CF . This improvement could be attributed to the more standardised and proactive approach to decreases in lung function and the increased clinician attention to patients with rapid decline, especially for patients with high baseline ppFEV₁.

Epidemiologic Study of Cystic Fibrosis: 25 years of observational research

The Epidemiologic Study of Cystic Fibrosis (ESCF) was a prospective observational study of over 32,000 people with cystic fibrosis (CF) from 250 clinical care sites in North America from 1994 to 2005. Begun as a pharmacovigilance study in connection with the approval of dornase alfa in 1993, ESCF was open to all people with CF treated at any participating site in the United States or Canada. In addition to obtaining safety and effectiveness data on dornase alfa, ESCF collected encounter-based data to characterize the natural history and management of CF with a special focus on lung disease. During the study, 32,178 patients reported at least one encounter, contributing 869,136 encounters, 622,592 pulmonary function tests, 432,896 cultures, and 118,563 pulmonary exacerbations treated with intravenous antibiotics. Although ESCF data collection concluded in 2005, through a collaboration with the U.S. Cystic Fibrosis Foundation Patient Registry, additional follow-up data through 2017 was available for two-thirds of patients. This allowed for updating of CF genotype and survival information. Fifty-six peer-reviewed publications (cited over 3600 times) resulted from this study. In this manuscript we summarize the published ESCF manuscripts in thematic groups with key study findings and brief comments, and speculate on how ESCF findings will inform future data registries and patient care practices.

Lung function determinants and mortality of children and adolescents with cystic fibrosis in South Africa 2007-2016

OBJECTIVES

Forced expiratory volume in 1 second (FEV1) is an important predictor of outcome in cystic fibrosis (CF). This study aimed to describe the change in lung function, nutritional status, and mortality of children with CF at a single center in Cape Town, South Africa, and identify factors associated with poor lung function and mortality.

METHODS

A retrospective study was conducted of children aged between 5 and 18 years between January 2007 and December 2016. At least two separate best annual FEV1 measurements were required for inclusion in the study.

RESULTS

A total of 143 children were followed up from which 107 study participants (median diagnosis age 5.5 months) were included. There was no statistically significant improvement from 2007 to 2016 in population mean FEV1 (2.5 ± 1.70 to -1.9 ± 1.70 [P = .1]) and body mass index (-0.7 ± 1.2 to -0.4 ± 1.2 [P = .3]) Z scores. FEV1 Z score declined by 0.17 per year. No significant correlation between FEV1 and age of diagnosis, sex, ethnicity, genotype, geographical location, pancreatic status, or infections was identified. On multiple stepwise regression analysis, FEV1 at age 6 was found to be the only independent predictor of mortality (adjusted odds ratio [95% CI] 0.5 [0.3-0.8]; P = .005).

CONCLUSION

FEV1 at age 6 was an independent predictor for CF-related mortality. Measurement of lung function in preschool children in SA with CF using more sensitive methods than spirometry is important to identify children at risk of poor outcomes.

Lung function changes before and after pulmonary exacerbation antimicrobial treatment in cystic fibrosis

BACKGROUND

In cystic fibrosis, observation of a lung function drop (as percent predicted forced expiratory volume in 1 s [FEV₁ ]; ppFEV₁ ) frequently precedes pulmonary exacerbation (PEx) diagnosis. Recovery of ppFEV₁ to a previous "baseline" is commonly used to assess antimicrobial treatment response. However, not all diagnosed PEx are associated with a ppFEV₁ drop, and it is unclear whether these are a different type of PEx from those associated with a ppFEV₁ drop.

METHODS

We analyzed pre- and posttreatment ppFEV₁ for PEx recorded in the Epidemiologic Study of Cystic Fibrosis from 2003 through 2005. Baseline, pretreatment, and follow-up ppFEV₁ were the best recorded within 12-months pre-PEx, the lowest recorded -30 to +3 days of treatment, and the best recorded during 6-month follow-up, respectively. Logistic regression models for return of ppFEV₁ to baseline during follow-up were developed separately for PEx with ≥10%, <10%, and no ppFEV₁ drop before treatment.

RESULTS

Of 15 147 PEx, 10 166 (67.1%), 3479 (23.0%), and 1502 (9.9%) presented with a ≥10%, <10%, or no ppFEV₁ drop at diagnosis, respectively. 19.5%, 35.2%, and 65.6% of PEx, respectively, had follow-up ppFEV₁ equal to or exceeding baseline; overall 27.7% of all PEx treatments resulted in complete recovery of baseline ppFEV₁ . Significant predictors of ppFEV₁ recovery at follow-up were younger patient age, absence of Aspergillus, lower baseline ppFEV₁ , fewer visits during the baseline, lower frequency of prior-year PEx, shorter elapsed time from baseline measure to treatment, smaller relative ppFEV₁ drop before treatment, and non intravenous (ie, oral or inhaled antibiotic) treatment. PEx with ≥10%, <10%, and no ppFEV₁ drop before treatment had only modest differences in covariate odds ratios associated with complete ppFEV₁ recovery.

CONCLUSIONS

Among the 10% of PEx presenting with no apparent ppFEV₁ drop, more than one-third resulted in a decreased ppFEV₁ during follow-up. Risk factors for this outcome were the same as those associated with lack of ppFEV₁ recovery among PEx with pretreatment ppFEV₁ drops. These results suggest that inherent FEV₁ variability, baseline and follow-up sampling methodologies, ppFEV₁ regression to the mean, and underlying lung disease progression complicate this approach for assessing effects of PEx and treatment response.

Optimizing outcomes of pulmonary exacerbations in cystic fibrosis

PURPOSE OF REVIEW

Pulmonary exacerbations are described as worsening of the daily symptoms of cystic fibrosis airways disease, typically with increased cough and sputum production. There are often associated signs such as weight loss and reduced lung function. These events occur frequently and are associated with considerable cost and morbidity. Although approved maintenance therapies are shown to reduce exacerbations, they still occur and are associated with poor outcomes despite treatment. Guidelines to define best practices found a paucity of evidence upon which to base recommendations.

RECENT FINDINGS

There are ongoing studies that are trying to build the evidence upon which to improve our practice. Antibiotics remain a core aspect of treatment, but there is high variance in practice patterns including selection of antibiotics and duration of therapy. In addition, there is a discordance between antibiotic susceptibility test results and clinical outcomes, suggesting we need better approaches to guide antibiotic selection.

SUMMARY

Treatment durations are highly variable but recent evidence has demonstrated worse outcomes with shorter durations; longer durations may be associated with complications of treatment, suggesting an optimal duration could be identified. New studies aim to define best practices to improve outcomes with treatment of pulmonary exacerbations.

Intravenous antibiotic use and exacerbation events in an adult cystic fibrosis centre: A prospective observational study

INTRODUCTION

In CF, people with higher FEV₁ are less aggressively treated with intravenous (IV) antibiotics, with resultant negative impact on their health outcomes. This could be entirely clinician-driven, but patient choice may also influence IV use. In this prospective observational study, we explored IV recommendations by clinicians and IV acceptance by adults with CF to understand how clinical presentations consistent with exacerbations resulted in IV use.

METHODS

Clinical presentations consistent with exacerbations, IV recommendation by clinicians and IV acceptance by patients were prospectively identified for every adult with CF in Sheffield throughout 2016, excluding those who had lung transplantation (n = 7) or on ivacaftor (n = 13). Relevant demographic data, e.g. %FEV₁, were extracted from medical records. Multi-level mixed-effects logistic regression models were used to compare IV recommendations vs non-recommendations for all clinical encounters, and IV acceptance vs non-acceptance for all IV recommendations.

RESULTS

Among 186 adults (median age 27 years, median FEV₁ 78.5%), there were 434 exacerbation events and 318 IV use episodes following 1010 clinical encounters. Only 254 (58.5%) of exacerbations were IV treated. A diagnosis of exacerbation, higher number of symptoms and lower %FEV₁ were independent predictors for IV recommendation by clinicians. Higher number of symptoms and lower %FEV₁ were also independent predictors for IV acceptance by adults with CF.

CONCLUSIONS

Lower IV use among adults with higher %FEV₁ was influenced by both clinicians' and patients' decisions. Using IV antibiotics as an exacerbation surrogate could under-estimate exacerbation rates and conceal differential treatment decisions according to varying clinical characteristics.

Treatment Setting and Outcomes of Cystic Fibrosis Pulmonary Exacerbations

RATIONALE

There are important gaps in knowledge of the optimal treatment of cystic fibrosis pulmonary exacerbations. Previous observational studies comparing inpatient with outpatient treatment have suffered from methodologic weaknesses, especially indication bias.

OBJECTIVES

We analyzed data from the Epidemiologic Study of Cystic Fibrosis using techniques to control for indication bias to determine whether there is an advantage to inpatient treatment of cystic fibrosis pulmonary exacerbations.

METHODS

We identified typical pulmonary exacerbations in patients ages 6 years and older during the 3-year observation period ending in 2005. In our primary analysis, we used the instrumental variables method, implemented using two-stage least squares regression, to evaluate the effect of the proportion of total time that intravenous treatment was administered on an inpatient (versus outpatient) basis on the likelihood of return of percent predicted forced expiratory volume in 1 second to greater than or equal to 90% of baseline post-treatment. We also evaluated two other indicators of treatment setting, three other measures of treatment response, and two alternative modeling techniques, and we also looked for differences between children and adults.

RESULTS

Our final analysis included 4,497 pulmonary exacerbations in 2,773 individual patients at 75 sites. We calculated the mean proportion of intravenous treatment time that was provided in the hospital setting at each site. The median across sites was 0.581 (interquartile range, 0.396-0.753). The median treatment success rate across sites was 74.2% (interquartile range, 67.9 to 79.2%). Univariate analysis and two-stage least squares models showed a positive relationship between treatment success and proportion of inpatient treatment days. Our primary model revealed an absolute increase of 9.08% (95% confidence interval, 2.55-15.61; P = 0.006) in the achievement of a return of percent predicted forced expiratory volume in 1 second to greater than or equal to 90% of baseline comparing complete inpatient treatment with no inpatient treatment. Treatment response was not related to duration of intravenous therapy. Similar results were found for all our modeling techniques and outcomes.

CONCLUSIONS

Patients with cystic fibrosis treated at sites with more reliance on inpatient treatment were more likely to achieve successful forced expiratory volume in 1 second recovery. There was no relationship between treatment duration and recovery of forced expiratory volume in 1 second.

Reevaluating approaches to cystic fibrosis pulmonary exacerbations

Cystic Fibrosis (CF) lung disease is characterized by intermittent acute episodes of worsening signs, symptoms, and pulmonary function; these so-called pulmonary exacerbations (PEx) appear to be important drivers of long-term declines in lung function, quality of life, and life expectancy. Surveillance for development of PEx and their treatment is a fundamental component of chronic CF management, and the merits of novel CF therapies are often judged based on their ability to reduce the frequency of PEx. Given the central role that they play, it is surprising how poorly PEx are understood, how thin is the evidence base for their treatment and how often they are left unrecognized and untreated in clinical practice. This paper reviews what is known and what is unknown regarding the nature of PEx, and discusses the impact of missed recognition and treatment of these episodes as well as the apparent variation in practice across CF care centers. The arguments supporting a liberal, highly sensitive approach to the diagnosis of PEx are presented, as well as recommendation for how care programs can achieve consistency in their early recognition and treatment. A stepwise approach to personalized treatment supported by close follow-up to ensure the successful resolution of all signs and symptoms will lead to the stabilization of patients' lung function and quality of life. Recommendations are made regarding important priorities for research into evidence-based approaches to improving the care of PEx.

Data that empower: The success and promise of CF patient registries

In this article, we describe existing CF registries with a focus on US registry data collected through the CF Foundation Patient Registry (CFFPR) and the Epidemiologic Study of CF (ESCF); highlight what registries have taught us regarding epidemiology of CF; showcase the impact of registries on research and clinical care; and discuss future directions. This manuscript complements the plenary address given by Dr Wayne Morgan at the 2016 North American CF Conference by summarizing the key points from the presentation and providing additional detail and information.

Do cystic fibrosis centres with the lowest FEV1 still use the least amount of intravenous antibiotics? A registry-based comparison of intravenous antibiotic use among adult CF centres in the UK

BACKGROUND

The Epidemiologic Study of Cystic Fibrosis using 1995-1996 and 2003-2005 data found that CF centres with lowest FEV₁ tended to use fewer intravenous antibiotics. We repeated the analyses using 2013-2014 UK CF registry data to determine if this was still the case.

METHODS

Analysing data for 2013 and 2014 separately, 28 adult CF centres were ranked according to median % age-adjusted FEV₁. The top 7 centres were placed in the 'upper quarter' (best FEV₁), the bottom 7 centres in 'lower quarter' (lowest FEV₁), and the rest in 'middle half'. IV use was stratified according to %FEV₁, then compared between the three groups.

RESULTS

Centres in the 'upper quarter' and 'middle half' used significantly more IV antibiotics compared to centres in the 'lower quarter' (van Elteren test P-value<0.001). Regression analyses showed that people with CF attending centres in the 'upper quarter' or 'middle half' are 30-50% more likely to receive at least one IV course per year compared to people attending centres in the 'lower quarter'.

CONCLUSIONS

CF centres with lowest FEV₁ are still distinguished by lower use of intravenous antibiotics.

Recovery of lung function following a pulmonary exacerbation in patients with cystic fibrosis and the G551D-CFTR mutation treated with ivacaftor

BACKGROUND

Pulmonary exacerbations (PEx) are associated with acute loss of lung function that is often not recovered after treatment. We investigated lung function recovery following PEx for ivacaftor- and placebo-treated subjects.

METHODS

Short- and long-term pulmonary function recovery data after PEx were summarized from a placebo-controlled trial in 161 cystic fibrosis patients≥12years old with the G551D-CFTR mutation (NCT00909532). Short-term recovery was measured 2 to 8weeks after treatment, and long-term recovery was determined at the end-of-study, both compared with baseline measured just prior to the PEx.

RESULTS

Fewer patients receiving ivacaftor experienced a PEx than patients receiving placebo (33.7% vs. 56.4%; P=0.004) and had a lower adjusted incidence rate of PEx (0.589 vs. 1.382; P<0.001). The proportion of PEx followed by full short-term recovery of percent predicted forced expiratory volume in 1s was similar (ivacaftor vs. placebo, 57.1% vs. 53.7), as was the proportion of patients having long-term recovery (46.4% vs. 47.7%).

CONCLUSIONS

Ivacaftor treatment reduces the frequency of PEx but does not improve on the rate of complete lung function recovery after PEx when compared with placebo.

An overview of international literature from cystic fibrosis registries. Part 5: Update 2012-2015 on lung disease

Patient registry data is a tool for defining the clinical course and risk factors in patients with less common diseases like Cystic Fibrosis. Forty-one registry-based reports on lung disease in Cystic Fibrosis were published between 2011 and 2015. The aim of this review is to describe and discuss the results of these reports, focusing on the risk factors for lung disease progression, specific microbiologic pathogens (e.g., non-tuberculous mycobacteria), disease complications, comparisons between registries of different countries, the impact of socio-economic status, and evaluation of benefits and costs of therapies. Techniques for improved clinical trial design were also studied. Pediatr Pulmonol. 2016;51:1251-1263. © 2016 Wiley Periodicals, Inc.

Forced Expiratory Volume in 1 Second Variability Helps Identify Patients with Cystic Fibrosis at Risk of Greater Loss of Lung Function

OBJECTIVE

To evaluate several alternative measures of forced expiratory volume in 1 second percent predicted (FEV1 %pred) variability as potential predictors of future FEV1 %pred decline in patients with cystic fibrosis.

STUDY DESIGN

We included 13,827 patients age ≥6 years from the Epidemiologic Study of Cystic Fibrosis 1994-2002 with ≥4 FEV1 %pred measurements spanning ≥366 days in both a 2-year baseline period and a 2-year follow-up period. We predicted change from best baseline FEV1 %pred to best follow-up FEV1 %pred and change from baseline to best in the second follow-up year by using multivariable regression stratified by 4 lung-disease stages. We assessed 5 measures of variability (some as deviations from the best and some as deviations from the trend line) both alone and after controlling for demographic and clinical factors and for the slope and level of FEV1 %pred.

RESULTS

All 5 measures of FEV1 %pred variability were predictive, but the strongest predictor was median deviation from the best FEV1 %pred in the baseline period. The contribution to explanatory power (R(2)) was substantial and exceeded the total contribution of all other factors excluding the FEV1 %pred rate of decline. Adding the other variability measures provided minimal additional value.

CONCLUSIONS

Median deviation from the best FEV1 %pred is a simple metric that markedly improves prediction of FEV1 %pred decline even after the inclusion of demographic and clinical characteristics and the FEV1 %pred rate of decline. The routine calculation of this variability measure could allow clinicians to better identify patients at risk and therefore in need of increased intervention.

The Evolution of Cystic Fibrosis Care

Cystic fibrosis (CF) is the most common life-limiting inherited illness of whites. Most of the morbidity and mortality in CF stems from impaired mucociliary clearance leading to chronic, progressive airways obstruction and damage. Significant progress has been made in the care of patients with CF, with advances focused on improving mucociliary clearance, minimizing inflammatory damage, and managing infections; these advances include new antimicrobial therapies, mucolytic and osmotic agents, and antiinflammatory treatments. More recently, researchers have targeted disease-causing mutations using therapies to promote gene transcription and improve channel function, which has led to impressive physiologic changes in some patients. As we develop more advanced, allele-directed therapies for the management of CF, it will become increasingly important to understand the specific genetic and environmental interactions that cause the significant heterogeneity of lung disease seen in the CF population. This understanding of CF endotypes will allow for more targeted, personalized therapies for future patients. This article reviews the genetic and molecular basis of CF lung disease, the treatments currently available, and novel therapies that are in development.

Risk factors for lung function decline in a large cohort of young cystic fibrosis patients

OBJECTIVE

To identify novel risk factors and corroborate previously identified risk factors for mean annual decline in FEV1% predicted in a large, contemporary, United States cohort of young cystic fibrosis (CF) patients.

METHODS

Retrospective observational study of participants in the EPIC Observational Study, who were Pseudomonas-negative and ≤12 years of age at enrollment in 2004-2006. The associations between potential demographic, clinical, and environmental risk factors evaluated during the baseline year and subsequent mean annual decline in FEV1 percent predicted were evaluated using generalized estimating equations.

RESULTS

The 946 participants in the current analysis were followed for a mean of 6.2 (SD 1.3) years. Mean annual decline in FEV1% predicted was 1.01% (95%CI 0.85-1.17%). Children with one or no F508del mutations had a significantly smaller annual decline in FEV1 compared to F508del homozygotes. In a multivariable model, risk factors during the baseline year associated with a larger subsequent mean annual lung function decline included female gender, frequent or productive cough, low BMI (<66th percentile, median in the cohort), ≥1 pulmonary exacerbation, high FEV1 (≥115% predicted, in the top quartile), and respiratory culture positive for methicillin-sensitive Staphylococcus aureus, methicillin-resistant S. aureus, or Stenotrophomonas maltophilia.

CONCLUSIONS

We have identified a range of risk factors for FEV1 decline in a large cohort of young, CF patients who were Pa negative at enrollment, including novel as well as previously identified characteristics. These results could inform the design of a clinical trial in which rate of FEV1 decline is the primary endpoint and identify high-risk groups that may benefit from closer monitoring.

Antibiotic treatment of signs and symptoms of pulmonary exacerbations: a comparison by care site

BACKGROUND

Antibiotic treatment of cystic fibrosis pulmonary exacerbations is inconsistent. Previous research has indicated that intravenous antibiotics are used more frequently at sites with better pulmonary function but it is not clear under what circumstances they are prescribed.

METHOD

Pediatric care sites enrolled in the Epidemiologic Study of Cystic Fibrosis were ranked by median FEV1 % predicted of children they followed. Reported presence of new signs and symptoms of a pulmonary exacerbation (PEx) and antibiotic treatment within 21 days were compared between those in the highest vs. those in the other quartiles, and adjusted for sociodemographic and clinical characteristics of patients.

RESULT

Highest quartile sites had a total of 2,454 children eligible for this analysis; lower quartile sites had a total of 5,487. The odds of having a PEx at highest vs. lower sites varied with how the PEx was defined, but high quartile sites were uniformly more likely to treat PEx with antibiotics. The adjusted odds ratio for treatment with any antibiotics of a PEx defined by the occurrence of one or two new signs and symptoms was 1.24 (95% CI 1.10, 1.40); for treatment of a PEx defined by the occurrence of three or four new signs and symptoms was 1.50 (95% CI 1.06, 2.11); and for treatment of a PEx defined by a drop of FEV(1) by ≥-15% was 1.33 (1.10, 1.60). The adjusted OR for treatment of these PEx with IV antibiotics was 1.11 (0.94, 1.32), 1.90 (1.32, 2.72), and 1.33 (1.10, 1.60), respectively.

CONCLUSION

ESCF care sites in the highest quartile for FEV(1) were more likely to prescribe antibiotics when patients present with either mild or overt evidence of PEx. While this may not be the only reason that their patients have superior median FEV(1), it is likely an important contributor.

Short-term and long-term response to pulmonary exacerbation treatment in cystic fibrosis

BACKGROUND

Treatment of pulmonary exacerbations (PEx) in cystic fibrosis (CF) varies widely with no consensus on management practices or best indicators of therapeutic success. To design trials evaluating PEx treatment factors, we characterise the heterogeneity of PEx care in adults and paediatrics, and correlate it with measures of clinical response including short-term and long-term lung function changes, change in symptom severity score and time to next intravenous antibiotic therapy.

METHODS

Data were used from a prospective observational study of patients with CF ≥10 years of age enrolled at six sites between 2007 and 2010. All were started on intravenous antibiotics for a clinically diagnosed PEx. Analysis of variance, logistic and Cox regression were used to examine the association of treatment factors with short-term and long-term clinical response.

RESULTS

Of 123 patients with CF (60% women, aged 23.1±10.2 years), 33% experienced <10% relative improvement in FEV1 during treatment, which was associated with failing to recover baseline lung function 3 months after treatment (OR=7.8, 95% CI 1.9 to 31.6, p=0.004) and a longer time to next intravenous antibiotic (HR=0.48, 95% CI 0.27 to 0.85, p=0.011). Symptom improvement was observed but was not associated with subsequent lung function or time to next antibiotic therapy, which had a median recurrence time of 143 days.

CONCLUSIONS

Immediate symptomatic or respiratory response to PEx treatment did not have a clear relationship with subsequent outcomes such as lung function or intravenous antibiotic-free interval. These results can inform future research of treatment regimens for PEx in terms of interventions and outcome measures.

TRIAL REGISTRATION

NCT00788359 (www.clinicaltrials.gov).

Pulmonary function outcomes for assessing cystic fibrosis care

BACKGROUND

Assessing cystic fibrosis (CF) patient quality of care requires the choice of an appropriate outcome measure. We looked systematically and in detail at pulmonary function outcomes that potentially reflect clinical practice patterns.

METHODS

Epidemiologic Study of Cystic Fibrosis data were used to evaluate six potential outcome variables (2002 best FVC, FEV(1), and FEF(25-75) and rate of decline for each from 2000 to 2002). We ranked CF care sites by outcome measure and then assessed any association with practice patterns and follow-up pulmonary function.

RESULTS

Sites ranked in the top quartile had more frequent monitoring, treatment of exacerbations, and use of chronic therapies and oral corticosteroids. The follow-up rate of pulmonary function decline was not predicted by site ranking.

CONCLUSIONS

Different pulmonary function outcomes associate slightly differently with practice patterns, although annual FEV(1) is at least as good as any other measure. Current site ranking only moderately predicts future ranking.