Adjunctive Systemic Corticosteroids for Pulmonary Exacerbations of Cystic Fibrosis

Rationale: Pulmonary exacerbations (PEx) remain the most common cause of morbidity, recurrent hospitalization, and diminished survival in people with cystic fibrosis (PWCF) and are characterized by excess inflammation. Corticosteroids are potent, widely available antiinflammatory drugs. However, corticosteroid efficacy data from randomized controlled trials in PWCF are limited. Objectives: To determine whether adjunctive systemic corticosteroid therapy is associated with improved outcomes in acute CF PEx. Methods: We performed a secondary analysis of Standardized Treatment of Pulmonary Exacerbations 2 (STOP2), a large multicenter randomized controlled trial of antimicrobial treatment durations for adult PWCF presenting with PEx, that included the use of corticosteroids as a stratification criterion in its randomization protocol. Corticosteroid treatment effects were determined after propensity score matching for covariates including age, sex, baseline forced expiratory volume in 1 second (FEV1), genotype, and randomization arm. The primary outcome measure was the change in percentage predicted FEV1 (ppFEV1). Symptoms, time to next PEx, and the incidence of adverse events (AEs) and serious adverse events (SAEs) were assessed as secondary endpoints. Phenotypic factors associated with the clinical decision to prescribe steroids were also investigated. Results: Corticosteroids were prescribed for 168 of 982 PEx events in STOP2 (17%). Steroid prescription was associated with decreased baseline ppFEV1, increased age, and female sex. Cotreatment with corticosteroids was independent of treatment arm allocation and did not result in greater mean ppFEV1 response, longer median time to next PEx, or more substantial symptomatic improvement compared with propensity-matched PWCF receiving antibiotics alone. AEs were not increased in corticosteroid-treated PWCF. The total number of SAEs-but not the number of corticosteroid-related or PEx-related SAEs-was higher among patients receiving corticosteroids. Conclusions: Empiric, physician-directed treatment with systemic corticosteroids, although common, is not associated with improved clinical outcomes in PWCF receiving antibiotics for PEx. Clinical trial registered with www.clinicaltrials.gov (NCT02781610).

Prevalence and Clinical Impact of Respiratory Viral Infections from the STOP2 Study of Cystic Fibrosis Pulmonary Exacerbations

Rationale: Rates of viral respiratory infection (VRI) are similar in people with cystic fibrosis (CF) and the general population; however, the associations between VRI and CF pulmonary exacerbations (PEx) require further elucidation.Objectives: To determine VRI prevalence during CF PEx and evaluate associations between VRI, clinical presentation, and treatment response.Methods: The STOP2 (Standardized Treatment of Pulmonary Exacerbations II) study was a multicenter randomized trial to evaluate different durations of intravenous antibiotic therapy for PEx. In this ancillary study, participant sputum samples from up to three study visits were tested for respiratory viruses using multiplex polymerase chain reactions. Baselines and treatment-associated changes in mean lung function (percent predicted forced expiratory volume in 1 s), respiratory symptoms (Chronic Respiratory Infection Symptom Score), weight, and C-reactive protein were compared as a function of virus detection. Odds of PEx retreatment within 30 days and future PEx hazard were modeled by logistic and Cox proportional hazards regression, respectively.Results: A total of 1,254 sputum samples from 621 study participants were analyzed. One or more respiratory viruses were detected in sputum samples from 245 participants (39.5%). Virus-positive participants were more likely to be receiving CF transmembrane conductance regulator modulator therapy (45% vs. 34%) and/or chronic azithromycin therapy (54% vs. 44%) and more likely to have received treatment for nontuberculous Mycobacterium infection in the preceding 2 years (7% vs. 3%). At study visit 1, virus-positive participants were more symptomatic (mean Chronic Respiratory Infection Symptom Score, 53.8 vs. 51.1), had evidence of greater systemic inflammation (log10 C-reactive protein concentration, 1.32 log10 mg/L vs. 1.23 log10 mg/L), and had a greater drop in percent predicted forced expiratory volume in 1 second from the prior 6-month baseline (5.8 vs. 3.6). Virus positivity was associated with reduced risk of future PEx (hazard ratio, 0.82; 95% confidence interval, 0.69-0.99; P = 0.034) and longer median time to next PEx (255 d vs. 172 d; P = 0.021) compared with virus negativity.Conclusions: More than one-third of STOP2 participants treated for a PEx had a positive test result for a respiratory virus with more symptomatic initial presentation compared with virus-negative participants, but favorable long-term outcomes. More refined phenotyping of PEx, taking VRIs into account, may aid in optimizing personalized management of PEx.Clinical trial registered with www.clinicaltrials.gov (NCT02781610).

Standards for the care of people with cystic fibrosis (CF); recognising and addressing CF health issues

This is the third in a series of four papers updating the European Cystic Fibrosis Society (ECFS) standards for the care of people with CF. This paper focuses on recognising and addressing CF health issues. The guidance was produced with wide stakeholder engagement, including people from the CF community, using an evidence-based framework. Authors contributed sections, and summary statements which were reviewed by a Delphi consultation. Monitoring and treating airway infection, inflammation and pulmonary exacerbations remains important, despite the widespread availability of CFTR modulators and their accompanying health improvements. Extrapulmonary CF-specific health issues persist, such as diabetes, liver disease, bone disease, stones and other renal issues, and intestinal obstruction. These health issues require multidisciplinary care with input from the relevant specialists. Cancer is more common in people with CF compared to the general population, and requires regular screening. The CF life journey requires mental and emotional adaptation to psychosocial and physical challenges, with support from the CF team and the CF psychologist. This is particularly important when life gets challenging, with disease progression requiring increased treatments, breathing support and potentially transplantation. Planning for end of life remains a necessary aspect of care and should be discussed openly, honestly, with sensitivity and compassion for the person with CF and their family. CF teams should proactively recognise and address CF-specific health issues, and support mental and emotional wellbeing while accompanying people with CF and their families on their life journey.

A Pilot Randomized Clinical Trial of Pediatric Cystic Fibrosis Pulmonary Exacerbations Treatment Strategies

Rationale: Despite the high prevalence and clear morbidity of cystic fibrosis (CF) pulmonary exacerbations (PEx), there have been no published clinical trials of outpatient exacerbation management. Objectives: To assess the feasibility of a pediatric clinical trial in which treatment of mild PEx is assigned randomly to immediate oral antibiotics or tailored therapy (increased airway clearance alone with oral antibiotics added only for prespecified criteria). The outcome on which sample size was based was the proportion of tailored therapy participants who avoided oral antibiotics during the 28 days after randomization. Methods: In this randomized, open-label, pilot feasibility study at 10 U.S. sites, children 6-18 years of age with CF were enrolled at their well baseline visits and followed through their first randomized PEx. Results: One hundred twenty-one participants were enrolled, of whom 94 (78%) reported symptoms of PEx at least once; of these, 81 (86%) had at least one exacerbation that met randomization criteria, of whom 63 (78%) were randomized. Feasibility goals were met, including enrollment, early detection of symptoms of PEx, and ability to randomize. Among the 33 participants assigned to tailored therapy, 10 (30%) received oral antibiotics, while 29 of 30 (97%) assigned to immediate antibiotics received oral antibiotics. The avoidance of oral antibiotics in 70% (95% confidence interval, 54-85%) was statistically significantly different from our null hypothesis that <10% of participants assigned to the tailored therapy arm would avoid antibiotics. Conclusions: Our pilot study demonstrates that conducting a randomized trial of oral antibiotic treatment strategies for mild PEx in children with CF is feasible and that assignment to a tailored therapy arm may reduce antibiotic exposure. Clinical trial registered with www.clinicaltrials.gov (NCT04608019).

Nasal airway inflammatory responses and pathogen detection in infants with cystic fibrosis

BACKGROUND

Detecting airway inflammation non-invasively in infants with cystic fibrosis (CF) is difficult. We hypothesized that markers of inflammation in CF [IL-1β, IL-6, IL-8, IL-10, IL-17A, neutrophil elastase (NE) and tumor necrosis factor (TNF-α)] could be measured in infants with CF from nasal fluid and would be elevated during viral infections or clinician-defined pulmonary exacerbations (PEx).

METHODS

We collected nasal fluid, nasal swabs, and hair samples from 34 infants with CF during monthly clinic visits, sick visits, and hospitalizations. Nasal fluid was isolated and analyzed for cytokines. Respiratory viral detection on nasal swabs was performed using the Luminex NxTAG® Respiratory Pathogen Panel. Hair samples were analyzed for nicotine concentration by reverse-phase high-performance liquid chromatography. We compared nasal cytokine concentrations between the presence and absence of detected respiratory viruses, PEx, and smoke exposure.

RESULTS

A total of 246 samples were analyzed. Compared to measurements in the absence of respiratory viruses, mean concentrations of IL-6, IL-8, TNF-α, and NE were significantly increased while IL-17A was significantly decreased in infants positive for respiratory viruses. IL-17A was significantly decreased and NE increased in those with a PEx. IL-8 and NE were significantly increased in infants with enteric pathogen positivity on airway cultures, but not P. aeruginosa or S. aureus. Compared to those with no smoke exposure, there were significantly higher levels of IL-6, IL-10, and NE in infants with detectable levels of nicotine.

CONCLUSIONS

Noninvasive collection of nasal fluid may identify inflammation in infants with CF during changing clinical or environmental exposures.

The association between gut microbiome and growth in infants with cystic fibrosis

BACKGROUND

In cystic fibrosis (CF), pathophysiologic changes in the gastrointestinal tract lead to malnutrition and altered gut microbiome. Microbiome alterations have been linked to linear growth, gut inflammation and respiratory manifestations. Elucidating these gut microbiome alterations may provide insight into future nutritional management in CF.

METHODS

Infants were followed for 12-months at four sites in the United States (US-CF) and Australia (AUS-CF). 16S rRNA gene sequencing was performed on longitudinal stool samples. Associations between microbial abundance and age, antibiotic prophylaxis, malnutrition, and breast feeding were evaluated using generalized linear mixed models. Taxonomic and predictive functional features were compared between groups.

RESULTS

Infants with CF (N = 78) were enrolled as part of a larger study. AUS-CF infants had higher mean weight-for-age z-scores than US-CF infants (p = 0.02). A subset of participants (CF N = 40, non-CF disease controls N = 10) provided stool samples for microbiome analysis. AUS-CF infants had lower stool alpha diversity compared to US-CF infants (p < 0.001). AUS-CF infants had higher relative abundance of stool Proteobacteria compared to US-CF infants which was associated with antibiotic prophylaxis (p < 0.001). Malnutrition (weight-for-age <10th percentile) was associated with depleted Lactococcus (p < 0.001). Antibiotic prophylaxis (p = 0.002) and malnutrition (p = 0.012) were linked with predicted decreased activity of metabolic pathways responsible for short chain fatty acid processing.

CONCLUSIONS

In infants with CF, gut microbiome composition and diversity differed between the two continents. Gut microbial diversity was not linked to growth. The relationship between malnutrition and antibiotic prophylaxis with reduced SCFA fermentation could have implications for gut health and function and warrants additional investigation.

Characteristics associated with cystic fibrosis-related pulmonary exacerbation treatment location

Previous studies indicate that hospital rather than home treatment of pulmonary exacerbations (PEx) in people with cystic fibrosis (CF) can improve outcomes. We evaluated characteristics of adult participants from the Standardized Treatment of Pulmonary Exacerbations (STOP2) trial with two separate comparisons: (1) those who were treated initially in hospital (N = 768) to those treated initially at home (N = 214) and (2) those treated only in hospital (N = 328) to those who were treated only at home or both at home and in hospital (N = 654). Participants who had Medicaid insurance, were treated for shorter duration, and traveled longer to reach treatment centers were more likely to have been treated initially in the hospital. Having Medicaid insurance, being treated for a shorter duration, and being male were associated with being treated only in the hospital. This analysis suggests decisions about the location of treatment are based on pragmatic factors rather than on clinical characteristics.

Re-examining baseline lung function recovery following IV-treated pulmonary exacerbations

CF registry pulmonary exacerbation (PEx) analyses have employed "before and after" spirometry recovery, where the best percent predicted forced expiratory volume in 1 s (ppFEV1) prior to PEx ("baseline") is compared to the best ppFEV1 <3 months post-PEx. This methodology lacks comparators and ascribes recovery failure to PEx. Herein, we describe 2014 CF Foundation Patient Registry PEx analyses including a comparator: recovery around nonPEx events, birthdays. 49.6% of 7357 individuals with PEx achieved baseline ppFEV1 recovery while 36.6% of 14,141 achieved baseline recovery after birthdays; individuals with both PEx and birthdays were more likely to recover baseline after PEx than after birthdays (47% versus 34%); mean ppFEV1 declines were 0.3 (SD=9.3) and 3.1 (9.3), respectively. Post-event measure number had more effect on baseline recovery than did real ppFEV1 loss in simulations, suggesting that PEx recovery analyses lacking comparators are prone to artifact and poorly describe PEx contributions to disease progression.

Antibiotic Regimen Changes during Cystic Fibrosis Pediatric Pulmonary Exacerbation Treatment

Rationale/Objectives: Antibiotic selection for in-hospital treatment of pulmonary exacerbations (PEx) in people with cystic fibrosis (CF) is typically guided by previous respiratory culture results or past PEx antibiotic treatment. In the absence of clinical improvement during PEx treatment, antibiotics are frequently changed in search of a regimen that better alleviates symptoms and restores lung function. The clinical benefits of changing antibiotics during PEx treatment are largely uncharacterized. Methods: This was a retrospective cohort study using the Cystic Fibrosis Foundation Patient Registry Pediatric Health Information System. PEx were included if they occurred in children with CF from 6 to 21 years old who had been treated with intravenous antibiotics between January 1, 2006, and December 31, 2018. PEx with lengths of stay <5 or >21 days or for which treatment was delivered in an intensive care unit were excluded. An antibiotic change was defined as the addition or subtraction of any intravenous antibiotic between Hospital Day 6 and the day before hospital discharge. Inverse probability of treatment weighting was used to adjust for disease severity and indication bias, which might influence a decision to change antibiotics. Results: In all, 4,099 children with CF contributed 18,745 PEx for analysis, of which 8,169 PEx (43.6%) included a change in intravenous antibiotics on or after Hospital Day 6. The mean change in pre- to post-treatment percent predicted forced expiratory volume in 1 second (ppFEV1) was 11.3 (standard error, 0.21) among events in which an intravenous antibiotic change occurred versus 12.2 (0.18) among PEx without an intravenous antibiotic change (P = 0.001). Similarly, the odds of return to ⩾90% of baseline ppFEV1 were less for PEx with antibiotic changes than for those without changes (odds ratio [OR], 0.89 [95% confidence interval (CI), 0.80-0.98]). The odds of returning to ⩾100% of baseline ppFEV1 did not differ between PEx with versus without antibiotic changes (OR, 0.94 [95% CI, 0.86-1.03]). In addition, PEx treated with intravenous antibiotic changes were associated with higher odds of future PEx (OR, 1.17 [95% CI, 1.12-1.22]). Conclusions: In this retrospective study, changing intravenous antibiotics during PEx treatment in children with CF was common and not associated with improved clinical outcomes.

Impact of lumacaftor/ivacaftor and tezacaftor/ivacaftor on treatment response in pulmonary exacerbations of F508del/F508del cystic fibrosis

BACKGROUND

Pulmonary exacerbations (PEx) remain a major cause of morbidity and mortality in people with cystic fibrosis (PWCF). Although the combination cystic fibrosis transmembrane conductance regulator (CFTR) modulators lumacaftor/ivacaftor and tezacaftor/ivacaftor have been shown to reduce PEx frequency, their influence on clinical and biochemical responses to acute PEx treatment is unknown.

METHODS

We performed a secondary analysis of STOP2, a large multicenter randomized controlled trial of antimicrobial treatment durations for adult PWCF presenting with PEx. Propensity score matching was used to compare outcomes in antibiotic-treated F508del/F508del PWCF receiving lumacaftor/ivacaftor or tezacaftor/ivacaftor with those observed in antibiotic-treated F508del/F508del controls not receiving CFTR modulator therapy. The primary outcome measure was the change in percent predicted FEV1 (ppFEV1) following completion of intravenous (IV) antibiotics, with post-antibiotic changes in symptoms, serum C-reactive protein (CRP) concentrations and weight included as secondary endpoints.

RESULTS

Among 982 PEx events in randomized PWCF, 480 were homozygous for F508del, of whom 289 were receiving lumacaftor/ivacaftor or tezacaftor/ivacaftor at initiation of antibiotic therapy. Modulator-treated F508del/F508del PWCF did not demonstrate greater improvements in ppFEV1, symptoms, serum CRP or weight following antibiotic treatment compared to modulator-naïve controls matched for age, sex, baseline ppFEV1, genotype, body mass index, initial CRP, initial symptoms, exacerbation history, diabetic status, randomization arm and concomitant medical therapy.

CONCLUSION

In the acute setting, CFTR modulator therapy with lumacaftor/ivacaftor or tezacaftor/ivacaftor does not convey additional clinical or biochemical advantage above standardized PEx treatment in F508del/F508del PWCF.

Evaluation of clinically relevant changes in the lung clearance index in children with cystic fibrosis and healthy controls

BACKGROUND

The limits of reproducibility of the lung clearance index (LCI) are higher in children with cystic fibrosis (CF) compared with healthy children, and it is currently unclear what defines a clinically meaningful change.

METHODS

In a prospective multisite observational study of children with CF and healthy controls (HCs), we measured LCI, FEV₁% predicted and symptom scores at quarterly visits over 2 years. Two reviewers performed a detailed review of visits to evaluate the frequency that between visit LCI changes outside ±10%, ±15%, ±20% represented a clinically relevant signal. In the setting of acute respiratory symptoms, we used a generalised estimating equation model, with a logit link function to determine the ability of LCI worsening at different thresholds to predict failure of lung function recovery at follow-up.

RESULTS

Clinically relevant LCI changes outside ±10%, ±15% and ±20% were observed at 25.7%, 15.0% and 8.3% of CF visits (n=744), respectively. The proportions of LCI changes categorised as noise, reflecting biological variability, were comparable between CF and HC at the 10% (CF 9.9% vs HC 13.0%), 15% (CF 4.3% vs HC 3.1%) and 20% (CF 2.4% vs HC 1.0%) thresholds. Compared with symptomatic CF visits without a worsening in LCI, events with ≥10% LCI increase were more likely to fail to recover baseline LCI at follow-up.

CONCLUSION

The limits of reproducibility of the LCI in healthy children can be used to detect clinically relevant changes and thus inform clinical care in children with CF.

Immunoreactive Trypsinogen in Infants Born to Women with Cystic Fibrosis Taking Elexacaftor–Tezacaftor–Ivacaftor

Most people with cystic fibrosis (CF) are diagnosed following abnormal newborn screening (NBS), which begins with measurement of immunoreactive trypsinogen (IRT) values. A case report found low concentrations of IRT in an infant with CF exposed to the CF transmembrane conductance regulator (CFTR) modulator, elexacaftor–tezacaftor–ivacaftor (ETI), in utero. However, IRT values in infants born to mothers taking ETI have not been systematically assessed. We hypothesized that ETI-exposed infants have lower IRT values than newborns with CF, CFTR-related metabolic syndrome/CF screen positive, inconclusive diagnosis (CRMS/CFSPID), or CF carriers. IRT values were collected from infants born in Indiana between 1 January 2020, and 2 June 2022, with ≥1 CFTR mutation. IRT values were compared to infants born to mothers with CF taking ETI followed at our institution. Compared to infants identified with CF (n = 51), CRMS/CFSPID (n = 21), and CF carriers (n = 489), ETI-exposed infants (n = 19) had lower IRT values (p < 0.001). Infants with normal NBS results for CF had similar median (interquartile range) IRT values, 22.5 (16.8, 30.6) ng/mL, as ETI-exposed infants, 18.9 (15.2, 26.5). IRT values from ETI-exposed infants were lower than for infants with abnormal NBS for CF. We recommend that NBS programs consider performing CFTR variant analysis for all ETI-exposed infants.

Association between early respiratory viral infections and structural lung disease in infants with cystic fibrosis

BACKGROUND

Infants with cystic fibrosis (CF) develop structural lung disease early in life, and viral infections are associated with progressive lung disease. We hypothesized that the presence of respiratory viruses would be associated with structural lung disease on computed tomography (CT) of the chest in infants with CF.

METHODS

Infants with CF were enrolled before 4 months of age. Multiplex PCR assays were performed on nasal swabs to detect respiratory viruses during routine visits and when symptomatic. Participants underwent CT imaging at approximately 12 months of age. Associations between Perth-Rotterdam Annotated Grid Morphometric Analysis for CF (PRAGMA-CF) CT scores and respiratory viruses and symptoms were assessed with Spearman correlation coefficients.

RESULTS

Sixty infants were included for analysis. Human rhinovirus was the most common virus detected, on 28% of tested nasal swabs and in 85% of participants. The median (IQR) extent of lung fields that was healthy based on PRAGMA-CF was 98.7 (0.8)%. There were no associations between PRAGMA-CF and age at first virus, or detection of any virus, including rhinovirus, respiratory syncytial virus, or parainfluenza. The extent of airway wall thickening was associated with ever having wheezed (ρ = 0.31, p = 0.02) and number of encounters with cough (ρ = 0.25, p = 0.0495).

CONCLUSIONS

Infants with CF had minimal structural lung disease. We did not find an association between respiratory viruses and CT abnormalities. Wheezing and frequency of cough were associated with early structural changes.

Real-world Associations of US Cystic Fibrosis Newborn Screening Programs With Nutritional and Pulmonary Outcomes

IMPORTANCE

Newborn screening (NBS) for cystic fibrosis (CF) has been universal in the US since 2010, but its association with clinical outcomes is unclear.

OBJECTIVE

To describe the real-world effectiveness of NBS programs for CF in the US on outcomes up to age 10 years.

DESIGN, SETTING, AND PARTICIPANTS

This was a retrospective cohort study using CF Foundation Patient Registry data from January 1, 2000, to December 31, 2018. The staggered implementation of NBS programs by state was used to compare longitudinal outcomes among children in the same birth cohort born before vs after the implementation of NBS for CF in their state of birth. Participants included children with an established diagnosis of CF born between January 1, 2000, to December 31, 2018, in any of the 44 states that implemented NBS for CF between 2003 and 2010. Data were analyzed from October 5, 2020, to April 22, 2022.

EXPOSURES

Birth before vs after the implementation of NBS for CF in the state of birth.

MAIN OUTCOMES AND MEASURES

Longitudinal trajectory of height and weight percentiles from diagnosis, lung function (forced expiratory volume in 1 second, [FEV1] percent predicted) from age 6 years, and age at initial and chronic infection with Pseudomonas aeruginosa using linear mixed-effects and time-to-event models adjusting for birth cohort and potential confounders.

RESULTS

A total of 9571 participants (4713 female participants [49.2%]) were eligible for inclusion, with 4510 (47.1%) in the pre-NBS cohort. NBS was associated with higher weight and height percentiles in the first year of life (weight, 6.0; 95% CI, 3.1-8.4; height, 6.6; 95% CI, 3.8-9.3), but these differences decreased with age. There was no association between NBS and FEV1 at age 6 years, but the percent-predicted FEV1 did increase more rapidly with age in the post-NBS cohort. NBS was associated with older age at chronic P aeruginosa infection (hazard ratio, 0.69; 95% CI, 0.54-0.89) but not initial P aeruginosa infection (hazard ratio, 0.88; 95% CI, 0.77-1.01).

CONCLUSIONS AND RELEVANCE

NBS for CF in the US was associated with improved nutritional status up to age 10 years, a more rapid increase in lung function, and delayed chronic P aeruginosa infection. In the future, as highly effective modulator therapies become available for infants with CF, NBS will allow for presymptomatic initiation of these disease-modifying therapies before irreversible organ damage.

Antipseudomonal treatment decisions during CF exacerbation management

BACKGROUND

Cystic fibrosis (CF) pulmonary exacerbation (PEx) treatment guidelines suggest that Pseudomonas aeruginosa (Pa) airway infection be treated with two antipseudomonal agents.

METHODS

We retrospectively studied treatment responses for STOP2 PEx treatment trial (NCT02781610) participants with a history of Pa infection. Mean lung function and symptom changes from intravenous (IV) antimicrobial treatment start to Visit 2 (7 to 10 days later) were compared between those receiving one, two, and three+ antipseudomonal classes before Visit 2 by ANCOVA. Odds of PEx retreatment with IV antimicrobials within 30 days and future IV-treated PEx hazard were modeled by logistic and Cox proportional hazards regression, respectively. Sensitivity analyses limited to the most common one-, two-, and three-class regimens, to only IV/oral antipseudomonal treatments, and with more stringent Pa infection definitions were conducted.

RESULTS

Among 751 participants, 50 (6.7%) were treated with one antipseudomonal class before Visit 2, while 552 (73.5%) and 149 (19.8%) were treated with two and with three+ classes, respectively. Females and participants with a negative Pa culture in the prior month were more likely to be treated with a single class. The most common single, double, and triple class regimens were beta-lactam (BL; n = 42), BL/aminoglycoside (AG; n = 459), and BL/AG/fluoroquinolone (FQ; n = 73). No lung function or symptom response, odds of retreatment, or future PEx hazard differences were observed by number of antipseudomonal classes administered in primary or sensitivity analyses.

CONCLUSIONS

We were unable to identify additional benefit when multiple antipseudomonal classes are used to treat PEx in people with CF and Pa.

Nutritional status and lung function in children with pancreatic-sufficient cystic fibrosis

BACKGROUND

There is a strong association between nutrition and long-term FEV1 in cystic fibrosis (CF), but studies have been driven by data from subjects with pancreatic insufficiency (PI-CF). We thus evaluated the association between body mass index (BMI) and FEV1 percent-predicted (FEV1pp) in children with pancreatic sufficiency (PS-CF) and contrasted it with the association in PI-CF.

METHODS

We utilized data from the CF Foundation Patient Registry. The cohort included children born 1995-2010, diagnosed <2 years of age, and who had annualized data on BMI percentile and FEV1pp at ages 6-16 years. Pancreatic status was defined based on pancreatic enzyme replacement therapy. The association between BMI and FEV1 was evaluated using linear and mixed-effects longitudinal regression.

RESULTS

There were 424 children with PS-CF and 7,849 with PI-CF. The association between BMI and FEV1 differed significantly by pancreatic status: each 10-pct higher BMI was associated with 2% [95%CI = 1.9-2.1] higher FEV1pp in PI-CF, compared to just 0.9% [0.5-1.3] in PS-CF (PINTERACTION < 0.001). Within the at-risk nutritional category (BMI <25pct), each 10-pct higher BMI was associated with 5% higher FEV1pp in PI-CF, but no significant increase in PS-CF. Moreover, in PS-CF, overweight/obesity (BMI ≥85pct) was associated with decreasing FEV1pp. In addition, FEV1pp decline through age 20 years in youth with PS-CF was modest (-0.6% per year) and independent of BMI (BMI*age PINTERACTION = 0.37).

CONCLUSIONS

In children with PS-CF, BMI remains an important determinant of lung function. However, it may be less critical to attain a BMI >50th percentile; and BMI ≥85th percentile may be detrimental.

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.

Comparative analysis of respiratory symptom scores to detect acute respiratory events in children with cystic fibrosis

BACKGROUND

Patient-reported outcomes (PROs) are important outcome measures in research and clinical practice. This study describes the longitudinal variability the Cystic Fibrosis Questionnaire-Revised (CFQ-R) Respiratory score and the Chronic Respiratory Infection Symptom Score (CRISS), as well as their ability to identify acute respiratory events in children with CF.

METHODS

In this prospective observational study, the parent-proxy (6 -13 years) and self-reported (6-18 years) CFQ-R Respiratory score and CRISS (6-18 years) were measured every 3 months over 2 years. The lung clearance index (LCI) and FEV₁ were also measured. We compared the diagnostic accuracy of the PROs in distinguishing acute respiratory events and clinically stable visits, using the minimal important difference of each PRO as the threshold.

RESULTS

A total of 98 children with CF were included. On average, the symptom scores did not change between clinically stable visits. The positive predictive value (PPV) and negative predictive value (NPV) of a ≥8.5-point worsening in the parent-proxy CFQ-R score to identify acute respiratory events (n=119) (PPV 70.2% and NPV 87.0%) were higher than for the self-reported CFQ-R score (PPV 58.9% and NPV 72.2%). The PPV and NPV of an ≥11-point change in the CRISS for acute respiratory events (n=137) was 56.5% and 79.6%, respectively. The PPV and NPV of all PROs were increased when combined with the LCI and/or FEV₁pp.

CONCLUSION

Symptoms scores differ in their ability to identify acute respiratory events in children with CF; PPV and NPV of all PROs were improved when combined with lung function outcomes.

Health care costs in a randomized trial of antimicrobial duration among cystic fibrosis patients with pulmonary exacerbations

BACKGROUND

The purpose of these analyses was to determine whether overall costs were reduced in cystic fibrosis (CF) patients experiencing pulmonary exacerbation (PEx) who received shorter versus longer durations of treatment.

METHODS

Among people with CF experiencing PEx, we calculated 30-day inpatient, outpatient, emergency room, and medication costs and summed these to derive total costs in 2020 USD. Using the Kaplan-Meier sample average (KMSA) method, we calculated adjusted costs and differences in costs within two pairs of randomized groups: early robust responders (ERR) randomized to receive treatment for 10 days (ERR-10 days) or 14 days (ERR-14 days), and non-early robust responders (NERR) randomized to receive treatment for 14 days (NERR-14 days) or 21 days (NERR-21 days).

RESULTS

Patients in the shorter treatment duration groups had shorter lengths of stay per hospitalization (mean ± standard deviation (SD) for ERR-10 days: 7.9 ± 3.0 days per hospitalization compared to 10.1 ± 4.2 days in ERR-14 days; for NERR-14 days: 8.7 ± 4.9 days per hospitalization compared to 9.6 ± 6.5 days in NERR-21 days). We found statistically significantly lower adjusted mean costs (95% confidence interval) among those who were randomized to receive shorter treatment durations (ERR-10 days: $60,800 ($59,150 - $62,430) vs $74,420 ($72,610 - $76,450) in ERR-14 days; NERR-14 days: $66,690 ($65,960-$67,400) versus $74,830 ($73,980-$75,650) in NERR-21 days).

CONCLUSIONS

Tied with earlier evidence that shorter treatment duration was not associated with worse clinical outcomes, our analyses indicate that treating with shorter antimicrobial durations can reduce costs without diminishing clinical outcomes.

Preliminary method for profiling volatile organic compounds in breath that correlate with pulmonary function and other clinical traits of subjects diagnosed with cystic fibrosis: a pilot study

Cystic fibrosis (CF) is characterized by chronic respiratory infections which progressively decrease lung function over time. Affected individuals experience episodes of intensified respiratory symptoms called pulmonary exacerbations (PEx) which accelerate pulmonary function decline and decrease survival. There is no standard classification for PEx, which results in treatments that are heterogeneous. Improving PEx classification and management is a significant priority for people with CF. Previous studies have shown volatile organic compounds (VOCs) in exhaled breath can be used as biomarkers because they are products of metabolic pathways dysregulated by different diseases. To provide insights on PEx classification and other clinical factors, exhaled breath was collected from subjects with CF, with some experiencing PEx and others at baseline. Exhaled breath was collected in Tedlar bags during tidal breathing for VOC analysis by solid phase microextraction coupled to gas chromatography-mass spectrometry. Statistical significance testing between quantitative and categorical clinical variables displayed percent-predicted forced expiratory volume in one second (FEV1pp) was decreased in subjects experiencing PEx. VOCs correlating with other clinical variables (body mass index, age, use of highly effective modulator therapies, and need for antibiotics) were also explored. VOCs correlating to potential confounding variables were removed and analyzed by regression for correlations with FEV1pp measurements. The VOC with the highest correlation with FEV1pp (3,7-dimethyldecane) also gave the lowest p-value when comparing subjects at baseline and during PEx. Receiver operator characteristic curves showed 3,7-dimethyldecane had a higher ability to classify PEx (area under the curve (AUC) = 0.91) relative to FEV1pp values at collection (AUC = 0.83). However, normalized ΔFEV1pp values had the highest capability to distinguish PEx (AUC = 0.93). These results show that exhaled VOCs may be a source of biomarkers for various clinical traits of CF, including PEx, that should be explored in larger sample cohorts and validation studies.

C-reactive protein (CRP) as a biomarker of pulmonary exacerbation presentation and treatment response

BACKGROUND

C-reactive protein (CRP) has been proposed as a biomarker for pulmonary exacerbation (PEx) diagnosis and treatment response. CRP >75mg/L has been associated with increased risk of PEx treatment failure. We have analyzed CRP measures as biomarkers for clinical response during the STOP2 PEx study (NCT02781610).

METHODS

CRP measures were collected at antimicrobial treatment start (V1), seven to 10 days later (V2), and two weeks after treatment end (V3). V1 log₁₀CRP concentrations and log₁₀CRP change from V1 to V3 correlations with clinical responses (changes in lung function and symptom score) were assessed by least squares regression. Odds of intravenous (IV) antimicrobial retreatment within 30 days and future PEx hazard associated with V1 and V3 CRP concentrations and V1 CRP >75 mg/L were studied by adjusted logistic regression and proportional hazards modeling, respectively.

RESULTS

In all, 951 of 982 STOP2 subjects (92.7%) had CRP measures at V1. V1 log₁₀CRP varied significantly by V1 lung function subgroup, symptom score quartile, and sex, but not by age subgroup. V1 log₁₀CRP correlated moderately with log₁₀CRP change at V3 (r²=0.255) but less so with lung function (r²=0.016) or symptom (r²=0.031) changes at V3. Higher V1 CRP was associated with greater response. CRP changes from V1 to V3 only weakly correlated with lung function (r²=0.061) and symptom (r²=0.066) changes. However, V3 log₁₀CRP was associated with increased odds of retreatment (P = .0081) and future PEx hazard (P = .0114).

DISCUSSION

Despite consistent trends, log₁₀CRP change was highly variable with only limited utility as a biomarker of PEx treatment response.

Prevalence, variability, and predictors of sinus surgery in pediatric patients with cystic fibrosis

INTRODUCTION

Chronic rhinosinusitis is common among individuals with cystic fibrosis (CF) and has an impact on quality of life. Sinus surgery is a treatment option, but minimal literature exists regarding prevalence and indications.

METHODS

Using the linked CF Foundation Patient Registry (CFFPR) - Pediatric Health Information Systems (PHIS) database, we investigated variability in receipt of surgery, predictors of surgery, and time to first surgery. We included individuals less than 18 receiving care between 2006 and 2015 at a CF Foundation care program that is also a PHIS-participating-hospital. We used logistic regression to examine predictors of receipt of surgery and a Kaplan-Meier curve to examine time to first surgery among those born 2005-2007.

RESULTS

There were 11,545 children and adolescents and 2156 (18.7%) received at least one surgery. Variation in number of surgeries was observed across hospitals (median: 63 [IQR, 33-110]). There was an inconsistent pattern between receipt of surgery and markers of disease severity; those receiving surgery having increased odds of treatment use and pulmonary exacerbations and decreased odds of lower lung function and body mass index. Among the cohort of young children, 159 (14%) had at least one surgery with a median age at first surgery of 5.6 (IQR, 3.9-7.0).

CONCLUSIONS

The use of sinus surgery is frequent, but variable, among children and adolescents. Clinical factors are associated with receipt of surgery, but further understanding is needed on other factors that impact variability in use. Our study indicates the need for additional evaluation of the management of CF-related CRS and indications for surgery.

Rates of adverse and serious adverse events in children with cystic fibrosis

BACKGROUND

Cystic fibrosis (CF) is an autosomal recessive disease characterized by chronic sinopulmonary symptoms and chronic gastrointestinal symptoms that begins in infancy. Children with CF are increasingly being included in clinical trials. In order to fully evaluate the impact of new therapies in future clinical trials, an understanding of baseline adverse event (AE) rates in children with CF is needed. To address this, we determined the rates of common AEs in pediatric patients with CF who participated in two clinical trials.

METHODS

We reviewed AEs for placebo recipients in the AZ0004 study and inhaled tobramycin recipients in the Early Pseudomonas Infection Control (EPIC) clinical trial. AEs were categorized based on Medical Dictionary for Regulatory Activities (MedDRA) coding classifications and pooled into common, batched AE descriptors. AE rates were estimated from negative binomial models according to age groups, severity of lung disease, and season.

RESULTS

A total of 433 children had 8,266 total AEs reported, or 18.1 (95% CI 17.0, 19.2) AEs per person per year. Respiratory AEs were the most commonly reported AEs, with a rate of 7.6 events per person-year. The total SAE rate was 0.33 per person per-year. Cough was the most commonly reported respiratory AE, with 61% of subjects reporting at least one episode of cough within 4 months. The rate ratio of any AE was higher in Spring, Fall, and Winter, compared with Summer.

CONCLUSIONS

AEs occur commonly in pediatric CF clinical trial participants. Season of enrollment could affect AE rates.

A Randomized Trial of Antimicrobial Duration for Cystic Fibrosis Pulmonary Exacerbation Treatment

RATIONALE

People with cystic fibrosis (CF) experience acute worsening of respiratory symptoms and lung function known as pulmonary exacerbations. Treatment with intravenous antimicrobials is common; however, there is scant evidence to support a standard treatment duration.

OBJECTIVE

Test differing durations of intravenous antimicrobials for CF exacerbations.

METHODS

STOP2 was a multi-center, randomized, controlled, clinical trial in exacerbation among adults with CF. After 7-10-days of treatment, participants exhibiting pre-defined lung function and symptom improvements were randomized to 10- or 14-days total antimicrobial duration; all others were randomized to 14- or 21-days.

MEASUREMENTS

The primary outcome was percent predicted forced expiratory volume in 1 second (ppFEV1) change from treatment initiation to two weeks after cessation. Among early responders non-inferiority of 10-days to 14-days was tested; superiority of 21-days compared to 14-days was compared for the others. Symptoms, weight, and adverse events were secondary.

RESULTS

Among 982 randomized, 277 met improvement criteria and were randomized to 10- or 14-days treatment; the remaining 705 received 21- or 14-days. Mean ppFEV1 change was 12.8 and 13.4 for 10- and 14-days, respectively, a ‒0.65 difference [95%CI ‒3.3, 2.0], excluding the pre-defined noninferiority margin. The 21- and 14-day arms experienced 3.3 and 3.4 mean ppFEV1 changes, a difference of ‒0.10 [‒1.3, 1.1]. Secondary endpoints and sensitivity analyses were supportive.

CONCLUSIONS

Among CF adults with early treatment improvement during exacerbation, ppFEV1 after 10-days of intravenous antimicrobials is not inferior to 14-days. For those with less improvement after one week, 21-days is not superior to 14-days. Clinical trial registration available at www.clinicaltrials.gov, ID: NCT02781610.

Determinants of lung disease progression measured by lung clearance index in children with cystic fibrosis

The lung clearance index (LCI) measured by the multiple breath washout (MBW) test is sensitive to early lung disease in children with cystic fibrosis. While LCI worsens during the preschool years in cystic fibrosis, there is limited evidence to clarify whether this continues during the early school age years, and whether the trajectory of disease progression as measured by LCI is modifiable.A cohort of children (healthy and cystic fibrosis) previously studied for 12 months as preschoolers were followed during school age (5-10 years). LCI was measured every 3 months for a period of 24 months using the Exhalyzer D MBW nitrogen washout device. Linear mixed effects regression was used to model changes in LCI over time.A total of 582 MBW measurements in 48 healthy subjects and 845 measurements in 64 cystic fibrosis subjects were available. The majority of children with cystic fibrosis had elevated LCI at the first preschool and first school age visits (57.8% (37 out of 64)), whereas all but six had normal forced expiratory volume in 1 s (FEV₁) values at the first school age visit. During school age years, the course of disease was stable (-0.02 units·year^-1 (95% CI -0.14-0.10). LCI measured during preschool years, as well as the rate of LCI change during this time period, were important determinants of LCI and FEV_1, at school age.Preschool LCI was a major determinant of school age LCI; these findings further support that the preschool years are critical for early intervention strategies.

Lung Clearance Index to Track Acute Respiratory Events in School-Age Children with Cystic Fibrosis

Rationale: The lung clearance index (LCI) is responsive to acute respiratory events in preschool children with cystic fibrosis (CF), but its utility to identify and manage these events in school-age children with CF is not well defined.Objectives: To describe changes in LCI with acute respiratory events in school-age children with CF.Methods: In a multisite prospective observational study, the LCI and FEV₁ were measured quarterly and during acute respiratory events. Linear regression was used to compare relative changes in LCI and FEV₁% predicted at acute respiratory events. Logistic regression was used to compare the odds of a significant worsening in LCI and FEV₁% predicted at acute respiratory events. Generalized estimating equation models were used to account for repeated events in the same subject.Measurements and Main Results: A total of 98 children with CF were followed for 2 years. There were 265 acute respiratory events. Relative to a stable baseline measure, LCI (+8.9%; 95% confidence interval, 6.5 to 11.3) and FEV₁% predicted (-6.6%; 95% confidence interval, -8.3 to -5.0) worsened with acute respiratory events. A greater proportion of events had a worsening in LCI compared with a decline in FEV₁% predicted (41.7% vs. 30.0%; P = 0.012); 53.9% of events were associated with worsening in LCI or FEV₁. Neither LCI nor FEV₁ recovered to baseline values at the next follow-up visit.Conclusions: In school-age children with CF, the LCI is a sensitive measure to assess lung function worsening with acute respiratory events and incomplete recovery at follow-up. In combination, the LCI and FEV₁ capture a higher proportion of events with functional impairment.

Reduction of pulmonary exacerbations in young children with cystic fibrosis during the COVID-19 pandemic

To assess the impact of COVID-19 restrictions on cystic fibrosis (CF) pulmonary exacerbations (PEx) we performed a retrospective review of PEx events at our CF Center and compared the rate of PEx in 2019 versus 2020. Restrictions on social interaction due to the COVID-19 pandemic were associated with a lower number of PEx events at our pediatric CF Center, suggesting that these restrictions also reduced exposure to other respiratory viral infection in children with CF.

Drug development for cystic fibrosis

The first regulatory approval for a drug developed specifically for cystic fibrosis (CF) occurred in 1993, and since then, several other drugs have been approved. Median predicted survival in people with CF in the United States has increased from approximately 30 years to 44.4 years over that same period. Highly effective modulators of the cystic fibrosis transmembrane conductance regulator became available to approximately 90% of people with CF ages 12 years and older in the United States in 2019 and in Europe in 2020. These transformative therapies will surely reduce morbidity and further extend longevity. The drug development pipeline is filled with therapies that address most aspects of CF disease. As survival and CF therapies advance, and the complexity of CF care increases, the process of drug development has become more sophisticated. In addition, detecting meaningful changes in outcome measures has become more difficult as the health status of people with CF improves. Innovative approaches are required to continue to advance drug development in CF. This review provides a general overview of drug development from the preclinical phase through Phase IV. Special considerations with respect to CF are integrated into the discussion of each phase of drug development. As CF care evolves, drug development must continue to evolve as well, until a one-time cure is available to all people with CF.

Oral antibiotic prescribing patterns for treatment of pulmonary exacerbations in two large pediatric CF centers

INTRODUCTION

Oral antibiotics are frequently prescribed for outpatient pulmonary exacerbations (PEx) in children with cystic fibrosis (CF). This study aimed to characterize oral antibiotic use for PEx and treatment outcomes at two large US CF centers.

METHODS

Retrospective, descriptive study of oral antibiotic prescribing practices among children with CF ages 6-17 years over 1 year. The care setting for antibiotic initiation (clinic or phone encounter) was determined and outcomes were compared.

RESULTS

A total of 763 oral antibiotic courses were prescribed to 312 patients aged 6-17 years (77% of 403 eligible patients) with a median of two courses per year (range: 1-10). Fifty-eight percent of prescriptions were provided over the phone. Penicillin was the most commonly prescribed antibiotic class (36% of prescriptions) but differences in antibiotic class prescriptions were noted between the two centers. Hospitalizations occurred within 3 months following 19% of oral antibiotic courses. Forced expiratory volume in 1 s (FEV₁ ) recovered to within 90% of prior baseline within 6 months in 87% of encounters; the mean (SD) % recovery was 99.6% (12.1%) of baseline. Outcomes did not differ between phone and clinic prescriptions.

CONCLUSIONS

Phone prescriptions, commonly excluded in studies of PEx, made up more than half of all oral antibiotic courses. Heterogeneity in prescribing patterns was observed between the two centers. Most patients had improvement in FEV₁ returning to near their prior baseline, but hospitalizations occurred in one-fifth following oral antibiotic treatment. Efforts to optimize PEx treatment must consider care that occurs over the phone; this is particularly important as the use of telemedicine increases.

Rapid lung function decline in adults with early-stage cystic fibrosis lung disease

RATIONALE

The prevalence of adults living with cystic fibrosis (CF) who have early-stage lung disease is increasing.

OBJECTIVES

Describe the prevalence and evaluate spirometric risk factors associated with the subgroup of patients with early-stage lung disease and FEV₁ decline of ≥5% predicted/year.

METHODS

Retrospective cohort study of patients ≥18 years with FEV₁% predicted ≥80% included in the US CF Foundation Patient Registry from 2010-2013. Regression models were developed to estimate FEV₁ rate of decline. Multivariable logistic analysis was used to assess if spirometric risk factors were associated with FEV₁ decline.

MEASUREMENTS AND MAIN RESULTS

3,029 subjects were in the study cohort. Approximately 15% of the cohort had a substantial decline in lung function ≥5% predicted/year. In multivariable models adjusted for confounders, FEV₁/FVC ratio <0.8 (Odds Ratio (OR) 1.63, 95% confidence interval (CI) 1.31 to 2.02) and history of FEV₁% predicted variability (OR 2.35,95%CI 1.74 to 3.18) were associated with rapid lung function decline.

CONCLUSIONS

Even among adults with early-stage lung disease, approximately 15% are shown to progress and experience a large decline in lung function. This reinforces the concept that lung function in early-stage CF is not normal or mild. Rather, lung function decline may be delayed, but not avoided, in these individuals. Variability in FEV₁% predicted and airway obstruction as measured by FEV1/FVC ratio may identify individuals at increased risk of decline. Adults with early-stage lung disease should be followed in clinic to monitor for onset of decline.

Predictors of pulmonary exacerbation treatment in cystic fibrosis

BACKGROUND

Most studies of pulmonary exacerbations (PEx) in cystic fibrosis (CF) focus on intravenous (IV)-treated PEx, though most PEx are treated with oral antibiotics. Our objectives were to describe predictors of antibiotic choice and outcomes for PEx initially identified in clinic.

METHODS

For each patient in the U.S. CF Foundation Patient Registry, we selected the first PEx recorded at a clinic visit in 2013-14 following a clinic visit without a PEx. We used multivariable logistic regression to determine associations between clinical characteristics and antibiotic treatment choice. We determined outcomes in the 90 days after the first PEx.

RESULTS

Among 14,265 patients with a PEx initially identified in clinic, 21.4% received no antibiotics, 61.5% received new oral and/or inhaled antibiotics, and 17.0% had IV antibiotics within 14 days. Compared to IV antibiotics, patients more likely to receive new oral and/or inhaled antibiotics: were male, <13 years old, had BMI >10th percentile or 18.5 kg/m², >90 days between clinic visits, FEV₁ > 70% predicted at the PEx, no prior-year IV-treated PEx, FEV₁ decline <10% predicted, and private insurance. Following the PEx, 30.3% of patients had no clinical encounters within 90 days. Treatment with IV antibiotics within 90 days occurred for 23.7% treated without antibiotics, 22.8% of new oral and/or inhaled antibiotics, and 27.1% of IV antibiotics.

CONCLUSION

Most PEx identified in clinic are treated with new oral and/or inhaled antibiotics. Markers of disease severity are associated with antibiotic treatment choice. Many patients had no follow-up evaluation within 90 days of treatment.

Secondhand smoke alters arachidonic acid metabolism and inflammation in infants and children with cystic fibrosis

BACKGROUND

Mechanisms that facilitate early infection and inflammation in cystic fibrosis (CF) are unclear. We previously demonstrated that children with CF and parental-reported secondhand smoke exposure (SHSe) have increased susceptibility to bacterial infections. SHSe hinders arachidonic acid (AA) metabolites that mediate immune function in patients without CF, and may influence CF immune dysfunction. We aimed to define SHSe's impact on inflammation mediators and infection in children with CF.

METHODS

Seventy-seven children with CF <10 years of age (35 infants <1 year; 42 children 1-10 years) were enrolled and hair nicotine concentrations measured as an objective surrogate of SHSe. AA signalling by serum and macrophage lipidomics, inflammation using blood transcriptional profiles and in vitro macrophage responses to bacterial infection after SHSe were assessed.

RESULTS

Hair nicotine concentrations were elevated in 63% of patients. Of the AA metabolites measured by plasma lipidomics, prostaglandin D₂ (PGD₂) concentrations were decreased in children with CF exposed to SHSe, and associated with more frequent hospitalisations (p=0.007) and worsened weight z scores (p=0.008). Children with CF exposed to SHSe demonstrated decreased expression of the prostaglandin genes PTGES3 and PTGR2 and overexpression of inflammatory pathways. These findings were confirmed using an in vitro model, where SHSe was associated with a dose-dependent decrease in PGD₂ and increased methicillin-resistant Staphylococcus aureus survival in human CF macrophages.

CONCLUSIONS

Infants and young children with CF and SHSe have altered AA metabolism and dysregulated inflammatory gene expression resulting in impaired bacterial clearance. Our findings identified potential therapeutic targets to halt early disease progression associated with SHSe in the young population with CF.

Quantitative chest computerized tomography and FEV1 equally identify pulmonary exacerbation risk in children with cystic fibrosis

BACKGROUND

Chest computerized tomography (CT) scores are associated with the frequency of future pulmonary exacerbations in people with cystic fibrosis (CF). However, cut-off values to identify children with mild lung disease with different risks for frequent future pulmonary exacerbations have not been identified.

METHODS

Chest CT scans were assessed using the Brody score for participants of the Pulmozyme Early Intervention Trial (PEIT) and Wisconsin Randomized Clinical Trial of CF Newborn Screening (WI RCT). We determined the area under the receiver operating characteristic (ROC) curve for Brody scores and forced expiratory volume in 1 s (FEV₁ ) to compare with the frequency of pulmonary exacerbations up to 10 years later.

RESULTS

There were 60 participants in the PEIT with mean (SD) age 10.6 (1.7) years at the time of the CT and 81 participants in the WI RCT with mean age 11.5 (3.0) years. The Brody score cut-off that best identified children at-risk for ≥0.3 annual pulmonary exacerbations was 3.6 in the PEIT and 2.1 in the WI RCT. There were no statistical differences between ROC curves for the Brody CT score and FEV₁ % predicted in either study (P ≥ 0.4).

CONCLUSIONS

CT score cut-off values that identify children with CF with mild lung disease at different risks for frequent pulmonary exacerbations over an extended follow up period are similar in separate cohorts. Brody scores and FEV₁ % predicted have similar abilities to identify these children, suggesting that FEV₁ % predicted alone may be adequate for predicting future frequency of pulmonary exacerbations.

Early life growth patterns persist for 12 years and impact pulmonary outcomes in cystic fibrosis

BACKGROUND

In children with cystic fibrosis (CF), recovery from growth faltering within 2 years of diagnosis (Responders) is associated with better growth and less lung disease at age 6 years. This study examined whether these benefits are sustained through 12 years of age.

METHODS

Longitudinal growth from 76 children with CF enrolled in the Wisconsin CF Neonatal Screening Project was examined and categorized into 5 groups: R₁₂, R₆, and R₂, representing Responders who maintained growth improvement to age 12, 6, and 2 years, respectively, and I₆ and N_6, representing Non-responders whose growth did and did not improve during ages 2-6 years, respectively. Lung disease was evaluated by % predicted forced expiratory volume in one second (FEV₁) and chest radiograph (CXR) scores.

RESULTS

Sixty-two percent were Responders. Within this group, 47% were R₁₂, 28% were R₆, and 25% were R₂. Among Non-responders, 76% were N₆. CF children with meconium ileus (MI) had worse lung function and CXR scores compared to other CF children. Among 53 children with pancreatic insufficiency without MI, R₁₂ had significantly better FEV₁ (97-99% predicted) and CXR scores during ages 6-12 years than N₆ (89-93% predicted). Both R₆ and R₂ experienced a decline in FEV₁ by ages 10-12 years.

CONCLUSIONS

Early growth recovery in CF is critical, as malnutrition during infancy tends to persist and catch-up growth after age 2 years is difficult. The longer adequate growth was maintained after early growth recovery, the better the pulmonary outcomes at age 12 years.

Study design considerations for the Standardized Treatment of Pulmonary Exacerbations 2 (STOP2): A trial to compare intravenous antibiotic treatment durations in CF

BACKGROUND

Pulmonary exacerbations (PEx) in cystic fibrosis (CF) are common and contribute to morbidity and mortality. Duration of IV antibiotic therapy to treat PEx varies widely in the US, and there are few data to guide treatment decisions.

METHODS

We combined a survey of CF stakeholders with retrospective analyses of a recent observational study of CF PEx to design a multicenter, randomized, prospective study comparing the efficacy and safety of different durations of IV antibiotics for PEx to meet the needs of people with CF and their caregivers.

RESULTS

IV antibiotic duration was cited as the most important PEx research question by responding CF physicians and top concern among surveyed CF patients/caregivers. During PEx, forced expiratory volume in 1s (FEV₁% predicted) and symptom responses at 7-10days of IV antibiotics identified two distinct groups: early robust responders (ERR) who subsequently experienced greater FEV₁ improvements compared to non-ERR (NERR). In addition to greater FEV₁ and symptom responses, only 14% of ERR patients were treated with IV antibiotics for >15days, compared with 45% of NERR patients.

CONCLUSIONS

A divergent trial design that evaluates subjects' interim improvement in FEV₁ and symptoms to tailor randomization to IV treatment duration (10 vs. 14days for ERR, 14 vs. 21days for NERR) may alleviate physician and patient concerns about excess or inadequate treatment. Such a study has the potential to provide evidence necessary to standardize IV antibiotic duration in CF PEx care -a first step to conducting PEx research of other treatment features.

Longitudinal development of initial, chronic and mucoid Pseudomonas aeruginosa infection in young children with cystic fibrosis

BACKGROUND

While the emergence of chronic and mucoid Pseudomonas aeruginosa (Pa) infection are both associated with poorer outcomes among CF patients, their relationship is poorly understood. We examined the longitudinal relationship of incident, chronic and mucoid Pa in a contemporary, young CF cohort in the current era of Pa eradication therapy.

METHODS

This retrospective cohort was comprised of patients in the U.S. CF Foundation Patient Registry born 2006-2015, diagnosed before age 2, and with at least 3 respiratory cultures annually. Incidence and age-specific prevalence of Pa infection stages (initial and chronic [≥ 3Pa+cultures in prior year]) and of mucoid Pa were summarized. Transition times and the interaction between Pa stage and acquisition of mucoid Pa were examined via Cox models.

RESULTS

Among the 5592 CF patients in the cohort followed to a mean age of 5.5years, 64% (n=3580) acquired Pa. Of those, 13% (n=455) developed chronic Pa and 17% (n=594) cultured mucoid Pa. Among those with mucoid Pa, 36% (211/594) had it on their first recorded Pa+culture, while mucoid Pa emerged at or after entering the chronic stage in 12% (73/594). Mucoidy was associated with significantly increased risk of transition to chronic Pa infection (HR=2.59, 95% CI 2.11, 3.19).

CONCLUSIONS

Two-thirds of early-diagnosed young children with CF acquired Pa during a median 5.6years of follow up, among whom 13% developed chronic Pa and 17% acquired mucoid Pa. Contrary to our hypothesis, 87% of young children who developed mucoid Pa did so before becoming chronically infected.

Poor recovery from cystic fibrosis pulmonary exacerbations is associated with poor long-term outcomes

RATIONALE

People with CF treated with IV antibiotics for a pulmonary exacerbation (PEx) frequently fail to recover to baseline FEV₁ . The long-term impact of these events has not been studied.

OBJECTIVES

To determine if a patient's spirometric recovery after a PEx is associated with time to next PEx within 1 year, the spirometric recovery after the next PEx, and/or the number of PEx episodes in the next 3 years.

METHODS

We used data from the CF Foundation Patient Registry from 2004 to 2011. We randomly selected one PEx per patient that met inclusion/exclusion criteria. Patients were defined as Non-Responders if their best FEV₁ (in liters) recorded in the 3 months after the PEx was <90% of the best FEV₁ (in liters) in the 6 months before the PEx. We compared Responders and Non-Responders using multivariable regression models.

RESULTS

We randomly chose 13 954 PEx episodes that met inclusion/exclusion criteria. A total of 2 762 (19.8%) patients were classified as Non-Responders. Non-Responders had a shorter median time to the next PEx, 235 (95%CI 218, 252) days, versus >365 days for Responders. Thirty-four percent of Non-Responders at the initial PEx were also Non-Reponders at the next PEx, versus 20% of Responders at the initial PEx. Non-Responders had more PEx episodes over the next 3 years, 4.99 (95%CI 4.84, 5.13), than Responders, 3.46 (95%CI 3.41, 3.51).

CONCLUSIONS

Poor recovery after a PEx is associated with a shorter time to the next PEx, increased risk of poor recovery at a second PEx, and more frequent subsequent PEx treatments.

Poor recovery from a pulmonary exacerbation does not lead to accelerated FEV1 decline

BACKGROUND

Patients with CF treated for pulmonary exacerbations (PEx) may experience faster subsequent declines in FEV1. Additionally, incomplete recovery to baseline FEV1 occurs frequently following PEx treatment. Whether accelerated declines in FEV1 are preceded by poor PEx recovery has not been studied.

METHODS

Using 2004 to 2011 CF Foundation Patient Registry data, we randomly selected one PEx among patients ≥6years of age with no organ transplantations, ≥12months of data before and after the PEx, and ≥1 FEV1 recorded within the 6months before and 3months after the PEx. We defined poor PEx recovery as the best FEV1 in the 3months after the PEx <90% of the best FEV1 in the 6months before the PEx. We calculated mean (95% CI) hazard ratios (HR) of having >5% predicted/year FEV1 decline and poor PEx recovery using multi-state Markov models.

RESULTS

From 13,954 PEx, FEV1 declines of >5% predicted/year were more likely to precede poor spirometric recovery, HR 1.17 (1.08, 1.26), in Markov models adjusted for age and sex. Non-Responders were less likely to have a subsequent fast FEV1 decline, HR 0.41 (0.37, 0.46), than patients who recovered to >90% of baseline FEV1 following PEx treatment.

CONCLUSIONS

Accelerated declines in FEV1 are more likely to precede a PEx with poor recovery than to occur in the following year. Preventing or halting declines in FEV1 may also have the benefit of preventing PEx episodes.

Standardized Treatment of Pulmonary Exacerbations (STOP) study: Observations at the initiation of intravenous antibiotics for cystic fibrosis pulmonary exacerbations

BACKGROUND

The Standardized Treatment of Pulmonary Exacerbations (STOP) program has the intent of defining best practices in the treatment of pulmonary exacerbations (PEx) in patients with cystic fibrosis (CF). The objective of this analysis was to describe the clinical presentations of patients admitted for intravenous (IV) antibiotics and enrolled in a prospective observational PEx study as well as to understand physician treatment goals at the start of the intervention.

METHODS

We enrolled adolescents and adults admitted to the hospital for a PEx treated with IV antibiotics. We recorded patient and PEx characteristics at the time of enrollment. We surveyed treating physicians on treatment goals as well as their willingness to enroll patients in various study designs. Additional demographic and clinical data were obtained from the CF Foundation Patient Registry.

RESULTS

Of 220 patients enrolled, 56% were female, 19% were adolescents, and 71% were infected with P. aeruginosa. The mean (SD) FEV₁ at enrollment was 51.1 (21.6)% predicted. Most patients (85%) experienced symptoms for ≥7days before admission, 43% had received IV antibiotics within the previous 6months, and 48% received oral and/or inhaled antibiotics prior to IV antibiotic initiation. Forty percent had ≥10% FEV₁ decrease from their best value recorded in the previous 6months, but for 20% of patients, their enrollment FEV₁ was their best FEV₁ recorded within the previous 6months. Physicians reported that their primary treatment objectives were lung function recovery (53%) and improvement of symptoms (47%) of PEx. Most physicians stated they would enroll patients in studies involving 10-day (72%) or 14-day (87%), but not 7-day (29%), treatment regimens.

CONCLUSIONS

Based on the results of this study, prospective studies are feasible and physician willingness for interventional studies of PEx exists. Results of this observational study will help design future PEx trials.

Rationalizing endpoints for prospective studies of pulmonary exacerbation treatment response in cystic fibrosis

BACKGROUND

Given the variability in pulmonary exacerbation (PEx) management within and between Cystic Fibrosis (CF) Care Centers, it is possible that some approaches may be superior to others. A challenge with comparing different PEx management approaches is lack of a community consensus with respect to treatment-response metrics. In this analysis, we assess the feasibility of using different response metrics in prospective randomized studies comparing PEx treatment protocols.

METHODS

Response parameters were compiled from the recent STOP (Standardized Treatment of PEx) feasibility study. Pulmonary function responses (recovery of best prior 6-month and 12-month FEV₁% predicted and absolute and relative FEV₁% predicted improvement from treatment initiation) and sign and symptom recovery from treatment initiation (measured by the Chronic Respiratory Infection Symptom Score [CRISS]) were studied as categorical and continuous variables. The proportion of patients retreated within 30days after the end of initial treatment was studied as a categorical variable. Sample sizes required to adequately power prospective 1:1 randomized superiority and non-inferiority studies employing candidate endpoints were explored.

RESULTS

The most sensitive endpoint was mean change in CRISS from treatment initiation, followed by mean absolute FEV₁% predicted change from initiation, with the two responses only modestly correlated (R²=.157; P<0.0001). Recovery of previous best FEV₁ was a problematic endpoint due to missing data and a substantial proportion of patients beginning PEx treatment with FEV₁ exceeding their previous best measures (12.1% >12-month best, 19.6% >6-month best). Although mean outcome measures deteriorated approximately 2-weeks post-treatment follow-up, the effect was non-uniform: 62.7% of patients experienced an FEV₁ worsening versus 49.0% who experienced a CRISS worsening.

CONCLUSIONS

Results from randomized prospective superiority and non-inferiority studies employing mean CRISS and FEV₁ change from treatment initiation should prove compelling to the community. They will need to be large, but appear feasible.

Diagnosis of Cystic Fibrosis in Screened Populations

OBJECTIVE

Cystic fibrosis (CF) can be difficult to diagnose, even when newborn screening (NBS) tests yield positive results. This challenge is exacerbated by the multitude of NBS protocols, misunderstandings about screening vs diagnostic tests, and the lack of guidelines for presumptive diagnoses. There is also confusion regarding the designation of age at diagnosis.

STUDY DESIGN

To improve diagnosis and achieve standardization in definitions worldwide, the CF Foundation convened a committee of 32 experts with a mission to develop clear and actionable consensus guidelines on diagnosis of CF with an emphasis on screened populations, especially the newborn population. A comprehensive literature review was performed with emphasis on relevant articles published during the past decade.

RESULTS

After reviewing the common screening protocols and outcome scenarios, 14 of 27 consensus statements were drafted that apply to screened populations. These were approved by 80% or more of the participants.

CONCLUSIONS

It is recommended that all diagnoses be established by demonstrating dysfunction of the CF transmembrane conductance regulator (CFTR) channel, initially with a sweat chloride test and, when needed, potentially with newer methods assessing membrane transport directly, such as intestinal current measurements. Even in babies with 2 CF-causing mutations detected via NBS, diagnosis must be confirmed by demonstrating CFTR dysfunction. The committee also recommends that the latest classifications identified in the Clinical and Functional Translation of CFTR project [http://www.cftr2.org/index.php] should be used to aid with CF diagnosis. Finally, to avoid delays in treatment, we provide guidelines for presumptive diagnoses and recommend how to determine the age of diagnosis.

Background and Epidemiology

Cystic fibrosis (CF) is the most common autosomal-recessive disease in white persons. Significant advances in therapies and outcomes have occurred for people with CF over the past 30 years. Many of these improvements have come about through the concerted efforts of the CF Foundation and international CF societies; networks of CF care centers; and the worldwide community of care providers, researchers, and patients and families. There are still hurdles to overcome to continue to improve the quality of life, reduce CF complications, prolong survival, and ultimately cure CF. This article reviews the epidemiology of CF, including trends in incidence and prevalence, clinical characteristics, common complications, and survival.

Early Life Growth Trajectories in Cystic Fibrosis are Associated with Pulmonary Function at Age 6 Years

OBJECTIVE

To determine whether severity of lung disease at age 6 years is associated with changes in nutritional status before age 6 within individual children with cystic fibrosis (CF).

STUDY DESIGN

Children with CF born between 1994 and 2005 and followed in the CF Foundation Patient Registry from age ≤2 through 7 years were assessed according to changes in annualized weight-for-length (WFL) percentiles between ages 0 and 2 years and body mass index (BMI) percentiles between ages 2 and 6 years. The association between growth trajectories before age 6 and forced expiratory volume in 1 second (FEV1)% predicted at age 6-7 years was evaluated using multivariable linear regression.

RESULTS

A total of 6805 subjects met inclusion criteria. Children with annualized WFL-BMI always >50th percentile (N = 1323 [19%]) had the highest adjusted mean (95% CI) FEV1 at 6-7 years (101.8 [100.1, 103.5]). FEV1 at 6-7 years for children whose WFL-BMI increased >10 percentile points by age 6 years was 98.3 (96.6, 100.0). This was statistically significantly higher than FEV1 for children whose WFL-BMI was stable (94.4 [92.6, 96.2]) or decreased >10 percentile points (92.9 [91.1, 94.8]). Among children whose WFL-BMI increased >10 percentile points, achieving and maintaining WFL-BMI >50th percentile at younger ages was associated with significantly higher FEV1 at 6-7 years.

CONCLUSIONS

Within-patient changes in nutritional status in the first 6 years of life are significantly associated with FEV1 at age 6-7 years. The establishment of a clear relationship between early childhood growth measurements and later lung function suggests that early nutritional interventions may impact on eventual lung health.

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.

Outcomes of infants with indeterminate diagnosis detected by cystic fibrosis newborn screening

BACKGROUND AND OBJECTIVES

Cystic fibrosis transmembrane conductance regulator-related metabolic syndrome (CRMS) describes asymptomatic infants with a positive cystic fibrosis (CF) newborn screen (NBS) but inconclusive diagnostic testing for CF. Little is known about the epidemiology and outcomes of CRMS. The goal of this study was to determine the prevalence, clinical features, and short-term outcomes of infants with CRMS.

METHODS

We analyzed data from the US CF Foundation Patient Registry (CFFPR) from 2010 to 2012. We compared demographic, diagnostic, anthropometric, health care utilization, microbiology, and treatment characteristics between infants with CF and infants with CRMS.

RESULTS

There were 1983 infants diagnosed via NBS between 2010 and 2012 reported to the CFFPR. By using the CF Foundation guideline definitions, 1540 and 309 infants met the criteria for CF and CRMS, respectively (CF:CRMS ratio = 5.0:1.0). Of note, 40.8% of infants with CRMS were entered into the registry with a clinical diagnosis of CF. Infants with CRMS tended to have normal nutritional indices. However, 11% of infants with CRMS had a positive Pseudomonas aeruginosa respiratory tract culture in the first year of life.

CONCLUSIONS

CRMS is a common outcome of CF NBS, and some infants with CRMS may develop features concerning for CF disease. A substantial proportion of infants with CRMS were assigned a clinical diagnosis of CF, which may reflect misclassification or clinical features not collected in the CFFPR.