Predicting weight gain in patients with cystic fibrosis on triple combination modulator

BACKGROUND

Cystic fibrosis (CF) is caused by CF transmembrane conductance regulator (CFTR) gene mutations producing dysfunctional CFTR proteins leading to progressive clinical disease. Elexacaftor-tezacaftor-ivacaftor (ETI) remarkably improves lung disease but is associated with substantial weight gain.

STUDY DESIGN AND METHODS

We performed a single-center longitudinal study predicting 6-month weight gain after ETI initiation. We used linear mixed effects modeling (LME) to determine association of ETI treatment with changing body mass index (BMI). Using linear regression, we examined BMI prediction models with distinct combinations of main effects to identify a model useful for patient counseling. We used up to eight commonly observed clinical characteristics as input variables (age, sex, percent predicted FEV1 [FEV1%], F508del homozygous state, pancreatic sufficiency, HgbA1c, prior modulator use and prior year number of pulmonary exacerbations).

RESULTS

We evaluated 154 patients (19-73 years old, 54% female, FEV1% = 19-121, 0-6 prior year pulmonary exacerbations). LME demonstrated an association between ETI use and weight increases. Exhaustive testing suggested a parsimonious linear regression model well-fitted to data that is potentially useful for counseling. The two variable model shows that on average, BMI decreases by 0.045 (95% Confidence Interval [CI] = -0.069 to -0.021, p < 0.001) for every year of age and increases by 0.322 (CI = 0.142 to 0.502, p = 0.001) for each additional prior year exacerbation at the time of ETI initiation.

INTERPRETATION

Young patients with many prior year pulmonary exacerbations likely have the largest 6 month weight gain after starting ETI.

A comparison of aminoglycoside antibiotic serum concentrations collected by peripheral veins and peripherally inserted central catheters in adults with cystic fibrosis

BACKGROUND

People with cystic fibrosis (PwCF) are frequently hospitalized for treatment of pulmonary exacerbation. The Cystic Fibrosis Foundation Pulmonary Guidelines support the use of intravenous aminoglycosides with therapeutic drug monitoring for the treatment of pulmonary exacerbation due to Pseudomonas aeruginosa. Serum intravenous tobramycin concentrations are commonly collected by peripheral venipuncture (PV). Discomfort associated with collection of samples by PV prompts collection via PICC, but the accuracy of intravenous tobramycin serum levels collected by PICC has not been documented in adult PwCF. The primary study objective was to evaluate the difference between intravenous tobramycin serum levels collected by PV and PICC in adult PwCF.

METHODS

The authors conducted a prospective case-control study of adult PwCF admitted to University of Utah Health for a pulmonary exacerbation receiving tobramycin by a single lumen PICC. The authors compared tobramycin peak and random serum levels collected by PV and PICC using a detailed flush and waste protocol.

RESULTS

The authors analyzed a total of 19 patients with peripheral and PICC samples. The mean tobramycin peak collected by PV (27.2 mcg/mL) was similar to the mean peak collected by PICC (26.9 mcg/mL) (paired samples Wilcoxon signed-rank test, p = .94). The correlation coefficient was 0.88 (95% CI = 0.85-0.91, p < .001).

CONCLUSION

Tobramycin serum samples collected by PICC appear to be similar in value to PV collections. Collecting aminoglycoside levels by PICC rather than PV may reduce patient discomfort and improve quality of life. Additional multicenter studies are needed to confirm these results.

Airway inflammation accelerates pulmonary exacerbations in cystic fibrosis

Airway inflammation underlies cystic fibrosis (CF) pulmonary exacerbations. In a prospective multicenter study of randomly selected, clinically stable adolescents and adults, we assessed relationships between 24 inflammation-associated molecules and the future occurrence of CF pulmonary exacerbation using proportional hazards models. We explored relationships for potential confounding or mediation by clinical factors and assessed sensitivities to treatments including CF transmembrane regulator (CFTR) protein synthesis modulators. Results from 114 participants, including seven on ivacaftor or lumacaftor-ivacaftor, representative of the US CF population during the study period, identified 10 biomarkers associated with future exacerbations mediated by percent predicted forced expiratory volume in 1 s. The findings were not sensitive to anti-inflammatory, antibiotic, and CFTR modulator treatments. The analyses suggest that combination treatments addressing RAGE-axis inflammation, protease-mediated injury, and oxidative stress might prevent pulmonary exacerbations. Our work may apply to other airway inflammatory diseases such as bronchiectasis and the acute respiratory distress syndrome.

Mutations in the C-terminal region of the bacteriophage exclusion protein PglX can selectively inactivate restriction in Salmonella

Salmonella enterica serovar Typhimurium strain LT2 is protected by two DNA restriction-modification systems (HsdRMS and Mod-Res) and a Type I bacteriophage exclusion (BREX) system (BrxA-L). The LB5000 strain was constructed to inactivate restriction but not methylation in all three systems and has been available for decades (L. R. Bullas and J. I. Ryu, J Bacteriol 156:471-474, 1983, https://doi.org/10.1128/jb.156.1.471-474.1983). However, this strain had been heavily mutagenized and contains hundreds of other mutations, including a few in DNA repair genes. Here, we describe the development of a strain that is only mutated for DNA restriction by the three systems and remains competent for DNA modification. We transferred mutations specific to DNA restriction from LB5000 to a wild-type LT2 background. The hsdR and res mutations affected only restriction in the wild-type background, but the brxC and pglZ mutations for the poorly understood BREX system also reduced modification. Amino acids in an unannotated conserved region of PglX in the BREX system were then randomized. Mutations were identified that specifically affected restriction at 37°C but were found to be temperature sensitive for restriction and methylation when tested at 30°C and 42°C. These mutations in PglX are consistent with a domain that communicates DNA methylation information to other BREX effector proteins. Finally, mutations generated in the specificity domain of PglX may have changed the DNA binding site recognized by the BREX system. IMPORTANCE The restriction system mutants constructed in this study will be useful for cloning DNA and transferring plasmids from other bacterial species into Salmonella. We verified which mutations in strain LB5000 resulted in loss of restriction for each restriction-modification system and the BREX system by moving these mutations to a wild-type Salmonella background. The methylase PglX was then mutagenized, which adds to our knowledge of the BREX system that is found in many bacteria but is not well understood. These PglX mutations affected restriction and methylation at different temperatures, which suggests that the C-terminal region of PglX may coordinate interactions between the methylase and other BREX system proteins.

Lung Function Decline in Cystic Fibrosis: Impact of Data Availability and Modeling Strategies on Clinical Interpretations

Rationale: Studies estimating the rate of lung function decline in cystic fibrosis have been inconsistent regarding the methods used. How the methodology used impacts the validity of the results and comparability between studies is unknown. Objectives: The Cystic Fibrosis Foundation established a work group whose tasks were to examine the impact of differing approaches to estimating the rate of decline in lung function and to provide analysis guidelines. Methods: We used a natural history cohort of 35,252 individuals with cystic fibrosis aged ⩾6 years in the Cystic Fibrosis Foundation Patient Registry (CFFPR), 2003-2016. Modeling strategies using linear and nonlinear forms of marginal and mixed-effects models, which have previously quantified the rate of forced expiratory volume in 1 second (FEV1) decline (percent predicted per year), were evaluated under clinically relevant scenarios of available lung function data. Scenarios varied by sample size (overall CFFPR, medium-sized cohort of 3,000 subjects, and small-sized cohort of 150), data collection/reporting frequency (encounter, quarterly, and annual), inclusion of FEV1 during pulmonary exacerbation, and follow-up length (<2 yr, 2-5 yr, entire duration). Results: Rate of FEV1 decline estimates (percent predicted per year) differed between linear marginal and mixed-effects models; overall cohort estimates (95% confidence interval) were 1.26 (1.24-1.29) and 1.40 (1.38-1.42), respectively. Marginal models consistently estimated less rapid lung function decline than mixed-effects models across scenarios, except for short-term follow-up (both were ∼1.4). Rate of decline estimates from nonlinear models diverged by age 30. Among mixed-effects models, nonlinear and stochastic terms fit best, except for short-term follow-up (<2 yr). Overall CFFPR analysis from a joint longitudinal-survival model implied that an increase in rate of decline of 1% predicted per year in FEV1 was associated with a 1.52-fold (52%) increase in the hazard of death/lung transplant, but the results exhibited immortal cohort bias. Conclusions: Differences were as high as 0.5% predicted per year between rate of decline estimates, but we found estimates were robust to lung function data availability scenarios, except short-term follow-up and older age ranges. Inconsistencies among previous study results may be attributable to inherent differences in study design, inclusion criteria, or covariate adjustment. Results-based decision points reported herein will support researchers in selecting a strategy to model lung function decline most reflective of nuanced, study-specific goals.

Inhaled mRNA therapy for treatment of cystic fibrosis: Interim results of a randomized, double-blind, placebo-controlled phase 1/2 clinical study

BACKGROUND

MRT5005, a codon-optimized CFTR mRNA, delivered by aerosol in lipid nanoparticles, was designed as a genotype-agnostic treatment for CF lung disease.

METHODS

This was a randomized, double-blind, placebo-controlled Phase 1/2 study performed in the US. Adults with 2 severe class I and/or II CFTR mutations and baseline ppFEV1 values between 50 and 90% were randomized 3:1 (MRT5005: placebo). Six dose levels of MRT5005 (4, 8, 12, 16, 20, and 24 mg) or placebo (0.9% Sodium Chloride) were administered by nebulization. The single ascending dose cohort was treated over a range from 8 to 24 mg; the multiple ascending dose cohort received five weekly doses (range 8-20 mg); and the daily dosing cohort received five daily doses (4 mg).

RESULTS

A total of 42 subjects were assigned to MRT5005 [31] or placebo [11]. A total of 14 febrile reactions were observed in 10 MRT5005-treated participants, which were mild [3] or moderate [11] in severity; two subjects discontinued related to these events. Additionally, two MRT5005-treated patients experienced hypersensitivity reactions, which were managed conservatively. The most common treatment emergent adverse events were cough and headache. No consistent effects on FEV1 were noted.

CONCLUSIONS

MRT5005 was generally safe and well tolerated through 28 days of follow-up after the last dose, though febrile and hypersensitivity reactions were noted. The majority of these reactions resolved within 1-2 days with supportive care allowing continued treatment with MRT5005 and careful monitoring. In this small first-in-human study, FEV1 remained stable after treatment, but no beneficial effects on FEV1 were observed.

Calibration and validation of modeled 5-year survival predictions among people with cystic fibrosis treated with the cystic fibrosis transmembrane conductance regulator modulator ivacaftor using United States registry data

OBJECTIVES

Cystic fibrosis (CF) is a rare genetic disease characterized by life-shortening lung function decline. Ivacaftor, a CF transmembrane conductance regulator modulator (CFTRm), was approved in 2012 for people with CF with specific gene mutations. We used real-world evidence of 5-year mortality impacts of ivacaftor in a US registry population to validate a CF disease-progression model that estimates the impact of ivacaftor on survival.

METHODS

The model projects the impact of ivacaftor vs. standard care in people with CF aged ≥6 years with CFTR gating mutations by combining parametric equations fitted to historical registry survival data, with mortality hazards adjusted for fixed and time-varying person-level characteristics. Disease progression with standard care was derived from published registry studies and the expected impact of ivacaftor on clinical characteristics was derived from clinical trials. Individual-level baseline characteristics of the registry ivacaftor-treated population were entered into the model; 5-year model-projected mortality with credible intervals (CrIs) was compared with registry mortality to evaluate the model's validity.

RESULTS

Post-calibration 5-year mortality projections closely approximated registry mortality in populations treated with standard care (6.4% modeled [95% CrI: 5.3% to 7.6%] vs. 6.0% observed) and ivacaftor (3.4% modeled [95% CrI: 2.7% to 4.4%] vs. 3.1% observed). The model accurately predicted 5-year relative risk of mortality (0.53 modeled [0.47 to 0.60] vs. 0.51 observed) in people treated with ivacaftor vs. standard care.

CONCLUSIONS

Modeled 5-year survival projections for people with CF initiating ivacaftor vs. standard care align closely with real-world registry data. Findings support the validity of modeling CF to predict long-term survival and estimate clinical and economic outcomes of CFTRm.

Ephrin Ligands are Upregulated in the Saliva of SARS‐CoV‐2 Infected Patients

Background

Patients infected with SARS‐CoV‐2 may develop severe lung disease characterized by respiratory distress, systemic thrombosis, or death. Molecular mechanisms responsible for severe cases of COVID‐19 remain unclear. We investigated the role of the Eph family receptor‐interacting ligands (ephrin‐A1 and ephrin‐B2) in COVID‐19 patients. Ephrin binding to its tyrosine kinase Eph receptor plays important roles in injury and inflammation. Serum levels of ephrin‐A1 ligand correlates positively with COVID‐19 severity (Mendoza et al, CellPress 2021). Based on this recent report, and the emerging role of Ephrin‐Eph signaling in lung injury, we hypothesize that ephrin‐mediated cytokine signaling is upregulated in epithelial and immune cells assayed from saliva samples obtained from seriously ill COVID‐19 patients seeking emergency evaluation and treatment.

Methods

Saliva samples were collected from patients (± SARS‐CoV‐2) in the University of Utah Emergency Department (ED) with IRB‐approved written consent. Saliva samples were incubated 1:1 in Streck Preservative (prior to EpCAM and CD45 labeling) or with 0.008% glutaraldehyde (following ELISA and multiplex immunoassays) in order to inactivate virus.

Results

Flow cytometric evaluation of saliva for EpCAM+ and CD45+ cells indicated that SARS‐CoV‐2 positive samples contain both epithelial and immune cell types (see Fig 1). Uninfected saliva samples (control) primarily contained EpCAM+ cells. COVID‐19 samples (n=67 patients) expressed higher levels of type 1 interferon [IFNγ1 and IFNα2 (p< 0.001)] vs control (n=64 patients). Interferon induced protein [IP‐10] was also upregulated in COVID‐19 patients (p<0.001), as well as several cytokines in the interleukin family [IL‐1β, IL‐6, IL‐8 (p<0.001) and IL‐12p70 (p<0.05)]. TNF‐α did not differ significantly between the ± SARS‐CoV‐2 samples evaluated. Using a subset of the +SARS‐CoV‐2 samples (n=20) and uninfected controls obtained from the ED (n=20), we show that both ephrin‐A1 and ephrin‐B2 ligands are significantly elevated in +SARS‐CoV‐2 samples vs. ED control samples (p<0.001). Ephrin‐B2 levels correlated negatively with IL‐12p70 (Pearson Correlation =‐0.53, p=.01).

Conclusion

Saliva is low risk to obtain and is a biologically relevant sample that can be used to reliably measure changes in epithelial and immune cell responses of COVID‐19 patients. Specifically, our study showed that ephrin‐A1 and ephrin‐B2 ligands are upregulated in the saliva of COVID‐19 patients in a TNF‐α independent manner and that ephrin‐B2 correlates negatively with IL‐12p70 (a potent pro‐inflammatory cytokine). Future studies are aimed at establishing ephrin ligands as a biomarker for severity of lung injury and improving understanding the patho‐physiology of SARS‐CoV‐2 infection.

Forced Expiratory Flow at 25%-75% Links COPD Physiology to Emphysema and Disease Severity in the SPIROMICS Cohort

BACKGROUND

Forced expiratory volume in 1 second (FEV₁) is central to the diagnosis of chronic obstructive pulmonary disease (COPD) but is imprecise in classifying disease burden. We examined the potential of the maximal mid-expiratory flow rate (forced expiratory flow rate between 25% and 75% [FEF_25%-75%]) as an additional tool for characterizing pathophysiology in COPD.

OBJECTIVE

To determine whether FEF_25%-75% helps predict clinical and radiographic abnormalities in COPD.

STUDY DESIGN AND METHODS

The SubPopulations and InteRediate Outcome Measures In COPD Study (SPIROMICS) enrolled a prospective cohort of 2978 nonsmokers and ever-smokers, with and without COPD, to identify phenotypes and intermediate markers of disease progression. We used baseline data from 2771 ever-smokers from the SPIROMICS cohort to identify associations between percent predicted FEF_25%-75% (%predFEF_25%-75%) and both clinical markers and computed tomography (CT) findings of smoking-related lung disease.

RESULTS

Lower %predFEF_25-75% was associated with more severe disease, manifested radiographically by increased functional small airways disease, emphysema (most notably with homogeneous distribution), CT-measured residual volume, total lung capacity (TLC), and airway wall thickness, and clinically by increased symptoms, decreased 6-minute walk distance, and increased bronchodilator responsiveness (BDR). A lower %predFEF_25-75% remained significantly associated with increased emphysema, functional small airways disease, TLC, and BDR after adjustment for FEV₁ or forced vital capacity (FVC).

INTERPRETATION

The %predFEF_25-75% provides additional information about disease manifestation beyond FEV₁. These associations may reflect loss of elastic recoil and air trapping from emphysema and intrinsic small airways disease. Thus, %predFEF_25-75% helps link the anatomic pathology and deranged physiology of COPD.

Enhanced epithelial sodium channel activity in neonatal Scnn1b mouse lung attenuates high oxygen-induced lung injury

Prolonged oxygen therapy leads to oxidative stress, epithelial dysfunction, and acute lung injury in preterm infants and adults. Heterozygous Scnn1b mice, which overexpress lung epithelial sodium channels (ENaC), and their wild-type (WT) C57Bl6 littermates were utilized to study the pathogenesis of high fraction inspired oxygen ([Formula: see text])-induced lung injury. Exposure to high [Formula: see text] from birth to postnatal (PN) day 11 was used to model oxidative stress. Chronic exposure of newborn pups to 85% O2 increased glutathione disulfide (GSSG) and elevated the GSH/GSSG redox potential (Eh) of bronchoalveolar lavage fluid (BALF). Longitudinal X-ray imaging and Evans blue-labeled-albumin assays showed that chronic 85% O2 and acute GSSG (400 µM) exposures decreased alveolar fluid clearance (AFC) in the WT lung. Morphometric analysis of WT pups insufflated with GSSG (400 µM) or amiloride (1 µM) showed a reduction in alveologenesis and increased lung injury compared with age-matched control pups. The Scnn1b mouse lung phenotype was not further aggravated by chronic 85% O2 exposure. These outcomes support the hypothesis that exposure to hyperoxia increases GSSG, resulting in reduced lung fluid reabsorption due to inhibition of amiloride-sensitive ENaC. Flavin adenine dinucleotide (FADH2; 10 µM) was effective in recycling GSSG in vivo and promoted alveologenesis, but did not impact AFC nor attenuate fibrosis following high [Formula: see text] exposure. In conclusion, the data indicate that FADH2 may be pivotal for normal lung development, and show that ENaC is a key factor in promoting alveologenesis, sustaining AFC, and attenuating fibrotic lung injury caused by prolonged oxygen therapy in WT mice.

Hypoxia induces expression of angiotensin-converting enzyme II in alveolar epithelial cells: Implications for the pathogenesis of acute lung injury in COVID-19

SARS-CoV-2 uptake by lung epithelial cells is a critical step in the pathogenesis of COVID-19. Viral entry is dependent on the binding of the viral spike protein to the angiotensin converting enzyme II protein (ACE2) on the host cell surface, followed by proteolytic cleavage by a host serine protease such as TMPRSS2. Infection of alveolar epithelial cells (AEC) in the distal lung is a key feature in progression to the acute respiratory distress syndrome (ARDS). We hypothesized that AEC expression of ACE2 is induced by hypoxia. In a murine model of hypoxic stress (12% FiO2), the total lung Ace2 mRNA and protein expression was significantly increased after 24 hours in hypoxia compared to normoxia (21% FiO2). In experiments with primary murine type II AEC, we found that exposure to hypoxia either in vivo (prior to isolation) or in vitro resulted in greatly increased AEC expression of both Ace2 (mRNA and protein) and of Tmprss2. However, when isolated type II AEC were maintained in culture over 5 days, with loss of type II cell characteristics and induction of type I cell features, Ace2 expression was greatly reduced, suggesting that this expression was a feature of only this subset of AEC. Finally, in primary human small airway epithelial cells (SAEC), ACE2 mRNA and protein expression were also induced by hypoxia, as was binding to purified spike protein. Hypoxia-induced increase in ACE2 expression in type II AEC may provide an explanation of the extended temporal course of human patients who develop ARDS in COVID-19.

SARS-CoV-2 innate effector associations and viral load in early nasopharyngeal infection

COVID‐19 causes severe disease with poor outcomes. We tested the hypothesis that early SARS‐CoV‐2 viral infection disrupts innate immune responses. These changes may be important for understanding subsequent clinical outcomes. We obtained residual nasopharyngeal swab samples from individuals who requested COVID‐19 testing for symptoms at drive‐through COVID‐19 clinical testing sites operated by the University of Utah. We applied multiplex immunoassays, real‐time polymerase chain reaction assays and quantitative proteomics to 20 virus‐positive and 20 virus‐negative samples. ACE‐2 transcripts increased with infection (OR =17.4, 95% CI [CI] =4.78–63.8) and increasing viral N1 protein transcript load (OR =1.16, CI =1.10–1.23). Transcripts for two interferons (IFN) were elevated, IFN‐λ1 (OR =71, CI =7.07–713) and IFN‐λ2 (OR =40.2, CI =3.86–419), and closely associated with viral N1 transcripts (OR =1.35, CI =1.23–1.49 and OR =1.33 CI =1.20–1.47, respectively). Only transcripts for IP‐10 were increased among systemic inflammatory cytokines that we examined (OR =131, CI =1.01–2620). We found widespread discrepancies between transcription and translation. IFN proteins were unchanged or decreased in infected samples (IFN‐γ OR =0.90 CI =0.33–0.79, IFN‐λ2,3 OR =0.60 CI =0.48–0.74) suggesting viral‐induced shut‐off of host antiviral protein responses. However, proteins for IP‐10 (OR =3.74 CI =2.07–6.77) and several interferon‐stimulated genes (ISG) increased with viral load (BST‐1 OR =25.1, CI =3.33–188; IFIT1 OR =19.5, CI =4.25–89.2; IFIT3 OR =245, CI =15–4020; MX‐1 OR =3.33, CI =1.44–7.70). Older age was associated with substantial modifications of some effects. Ambulatory symptomatic patients had an innate immune response with SARS‐CoV‐2 infection characterized by elevated IFN, proinflammatory cytokine and ISG transcripts, but there is evidence of a viral‐induced host shut‐off of antiviral responses. Our findings may characterize the disrupted immune landscape common in patients with early disease.

SARS-CoV-2 Innate Effector Associations and Viral Load in Early Nasopharyngeal Infection

To examine innate immune responses in early SARS-CoV-2 infection that may change clinical outcomes, we compared nasopharyngeal swab data from 20 virus-positive and 20 virus-negative individuals. Multiple innate immune-related and ACE-2 transcripts increased with infection and were strongly associated with increasing viral load. We found widespread discrepancies between transcription and translation. Interferon proteins were unchanged or decreased in infected samples suggesting virally-induced shut-off of host anti-viral protein responses. However, IP-10 and several interferon-stimulated gene proteins increased with viral load. Older age was associated with modifications of some effects. Our findings may characterize the disrupted immune landscape of early disease.

Impact of low-level fine particulate matter and ozone exposure on absences in K-12 students and economic consequences

High air pollution levels are associated with school absences. However, low level pollution impacts on individual school absences are under-studied. Understanding the variability of pollution at individual schools within an urban region could improve school recess decisions, better identify local pollution sources, and improve local economic impact assessments by providing granular information relevant to specific schools. We modelled PM_2.5 and ozone concentrations at 36 schools from July 2015 to June 2018 using data from a dense, research grade regulatory sensor network. We determined exposures and daily absences at each school. We used a generalized estimating equations model to retrospectively estimate rate ratios for association between outdoor pollutant concentrations and school absences. We estimated lost school revenue, productivity, and family economic burden. PM_2.5 and ozone concentrations and absence rates vary across the School District. Pollution exposure was associated with a rate ratio as high as 1.02 absences per μg m^-3 and 1.01 per ppb increase for PM_2.5 and ozone, respectively. Significantly, even PM_2.5 and ozone exposure below the air quality index breakpoints for good air quality (<12.1 μg m^-3 and <55 ppb, respectively) was associated with positive rate ratios of absences: 1.04 per μg m^-3 and 1.01 per ppb increase, respectively. Granular local measurements enabled demonstration of air pollution impacts that varied between schools and were undetectable with averaged pollution levels. Reducing pollution by 50% would save $426000 per year districtwide. Pollution reduction benefits would be greatest in schools located in socioeconomically disadvantaged areas. Heterogeneity in exposure, disproportionately affecting socioeconomically disadvantaged schools, points to the need for fine resolution exposure estimation. The economic cost of absences associated with air pollution is substantial even excluding indirect costs such as hospital visits and medication. These findings may help elucidate the differential burden on individual schools and inform local decisions about recess and regulatory considerations for localized pollution sources.

Evaluation of a five-year predicted survival model for cystic fibrosis in later time periods

We evaluated a multivariable logistic regression model predicting 5-year survival derived from a 1993-1997 cohort from the United States Cystic Fibrosis (CF) Foundation Patient Registry to assess whether therapies introduced since 1993 have altered applicability in cohorts, non-overlapping in time, from 1993-1998, 1999-2004, 2005-2010 and 2011-2016. We applied Kaplan-Meier statistics to assess unadjusted survival. We tested logistic regression model discrimination using the C-index and calibration using Hosmer-Lemeshow tests to examine original model performance and guide updating as needed. Kaplan-Meier age-adjusted 5-year probability of death in the CF population decreased substantially during 1993-2016. Patients in successive cohorts were generally healthier at entry, with higher average age, weight and lung function and fewer pulmonary exacerbations annually. CF-related diabetes prevalence, however, steadily increased. Newly derived multivariable logistic regression models for 5-year survival in new cohorts had similar estimated coefficients to the originals. The original model exhibited excellent calibration and discrimination when applied to later cohorts despite improved survival and remains useful for predicting 5-year survival. All models may be used to stratify patients for new studies, and the original coefficients may be useful as a baseline to search for additional but rare events that affect survival in CF.

High-mobility group box-1 increases epithelial sodium channel activity and inflammation via the receptor for advanced glycation end products

Cystic fibrosis (CF) lung disease persists and remains life-limiting for many patients. Elevated high-mobility group box-1 protein (HMGB-1) levels and epithelial sodium channel hyperactivity (ENaC) are hallmark features of the CF lung. The objective of this study was to better understand the pathogenic role of HMGB-1 signaling and ENaC in CF airway cells. We hypothesize that HMGB-1 links airway inflammation [via signaling to the receptor for advanced glycation end products (RAGE)] and airway surface liquid dehydration (via upregulation of ENaC) in the CF lung. We calculated equivalent short-current (I_sc) and single-channel ENaC open probability (P_o) in normal and CF human small airway epithelial cells (SAEC) in the presence and absence of human HMGB-1 peptide (0.5 μg/mL). In normal SAECs, HMGB-1 increased amiloride-sensitive I_sc and elevated ENaC P_o from 0.15 ± 0.03 to 0.28 ± 0.04 (P < 0.01). In CF SAECs, ENaC P_o increased from 0.45 ± 0.06 to 0.73 ± 0.04 (P < 0.01). Pretreatment with 1 μM FPS-ZM1 (a RAGE inhibitor) attenuated all HMGB-1 effects on ENaC current in normal and CF SAECs. Confocal analysis of SAECs indicates that nuclear size and HMBG-1 localization can be impacted by ENaC dysfunction. Masson's trichrome labeling of mouse lung showed that intraperitoneally injected HMGB-1 significantly increased pulmonary fibrosis. Bronchoalveolar lavage fluid from HMGB-1-treated mice showed significant increases in IL-1β, IL-10, IL-6, IL-27, IL-17A, IFN-β, and granulocyte-macrophage colony-stimulating factor compared with vehicle-injected mice (P < 0.05). These studies put forth a new model in which HMGB-1 signaling to RAGE plays an important role in perpetuating ENaC dysfunction and inflammation in the CF lung.

Modeling long-term health outcomes of patients with cystic fibrosis homozygous for F508del-CFTR treated with lumacaftor/ivacaftor

BACKGROUND

Lumacaftor/ivacaftor combination therapy is efficacious and generally safe for patients with cystic fibrosis (CF) homozygous for the F508del-CF transmembrane conductance regulator (CFTR) mutation. However, long-term survival benefits of lumacaftor/ivacaftor (LUM/IVA) cannot yet be quantified. Simulation models can provide predictions about long-term health outcomes. In this study, we aimed to project long-term health outcomes of LUM/IVA plus standard care (SC) in patients with CF homozygous for F508del-CFTR.

METHODS

This modeling study was an individual patient simulation in US patients aged ⩾6 years with CF, homozygous for F508del-CFTR. The primary outcome was projected survival among (a) a cohort of patients who ever initiated LUM/IVA, accounting for treatment discontinuations, and (b) a cohort of patients who remain on continuous LUM/IVA. Patient characteristics and model parameters were derived from clinical trials: VX14-809-109, VX13-809-011B, TRAFFIC/TRANSPORT, and PROGRESS; published literature; and the US CF Foundation Patient Registry.

RESULTS

Lumacaftor/ivacaftor + SC is expected to increase median survival by 6.1 years versus SC alone, accounting for treatment discontinuations. The incremental median predicted survival versus SC assuming initiation of LUM/IVA at ages 6, 12, 18, and 25 years was 17.7, 12.6, 8.0, and 3.8 years, respectively. Assuming lifetime treatment with LUM/IVA, incremental median survival was predicted to be 7.8 years longer in the LUM/IVA + SC cohort. Initiating LUM/IVA at ages 6, 12, 18, and 25 years and assuming lifetime treatment resulted in incremental median predicted survival of 23.4, 18.2, 11.0, and 4.8 years, respectively.

CONCLUSIONS

Lumacaftor/ivacaftor is projected to increase survival for patients with CF. Initiation at an early age and treatment persistence result in further increments in projected survival.

Prospective multicenter randomized patient recruitment and sample collection to enable future measurements of sputum biomarkers of inflammation in an observational study of cystic fibrosis

BACKGROUND

Biomarkers of inflammation predictive of cystic fibrosis (CF) disease outcomes would increase the power of clinical trials and contribute to better personalization of clinical assessments. A representative patient cohort would improve searching for believable, generalizable, reproducible and accurate biomarkers.

METHODS

We recruited patients from Mountain West CF Consortium (MWCFC) care centers for prospective observational study of sputum biomarkers of inflammation. After informed consent, centers enrolled randomly selected patients with CF who were clinically stable sputum producers, 12 years of age and older, without previous organ transplantation.

RESULTS

From December 8, 2014 through January 16, 2016, we enrolled 114 patients (53 male) with CF with continuing data collection. Baseline characteristics included mean age 27 years (SD = 12), 80% predicted forced expiratory volume in 1 s (SD = 23%), 1.0 prior year pulmonary exacerbations (SD = 1.2), home elevation 328 m (SD = 112) above sea level. Compared with other patients in the US CF Foundation Patient Registry (CFFPR) in 2014, MWCFC patients had similar distribution of sex, age, lung function, weight and rates of exacerbations, diabetes, pancreatic insufficiency, CF-related arthropathy and airway infections including methicillin-sensitive or -resistant Staphylococcus aureus, Pseudomonas aeruginosa, Burkholderia cepacia complex, fungal and non-tuberculous Mycobacteria infections. They received CF-specific treatments at similar frequencies.

CONCLUSIONS

Randomly-selected, sputum-producing patients within the MWCFC represent sputum-producing patients in the CFFPR. They have similar characteristics, lung function and frequencies of pulmonary exacerbations, microbial infections and use of CF-specific treatments. These findings will plausibly make future interpretations of quantitative measurements of inflammatory biomarkers generalizable to sputum-producing patients in the CFFPR.

The Clinical Biology of Cystic Fibrosis Transmembrane Regulator Protein: Its Role and Function in Extrapulmonary Disease

Normal cystic fibrosis (CF) transmembrane regulator (CFTR) protein has multiple functions in health and disease. Many mutations in the CFTR gene produce abnormal or absent protein. CFTR protein dysfunction underlies the classic CF phenotype of progressive pulmonary and GI pathology but may underlie diseases not usually associated with CF. This review highlights selected extrapulmonary disease that may be associated with abnormal CFTR. Increasing survival in CF is associated with increasing incidence of diseases associated with aging. CFTR dysfunction in older individuals may have novel effects on glucose metabolism, control of insulin release, regulation of circadian rhythm, and cancer cell pathophysiology. In individuals who have cancers with acquired CFTR suppression, their tumors may more likely exhibit rapid expansion, epithelial-to-mesenchymal transformation, abnormally reduced apoptosis, and increased metastatic potential. The new modulators of CFTR protein synthesis could facilitate the additional exploration needed to better understand the unfolding clinical biology of CFTR in human disease, even as they revolutionize treatment of patients with CF.

Right-to-left ventricular end diastolic diameter ratio in severe sepsis and septic shock

PURPOSE

The ratio of right ventricular end-diastolic diameter (EDD) to left ventricular EDD (RV/LV) is a measure predictive of right ventricular failure. We hypothesized that an increase in RV/LV would be associated with poor prognosis in severe sepsis and septic shock.

MATERIALS AND METHODS

This is a retrospective chart review of patients with severe sepsis and septic shock admitted to a medical intensive care unit (ICU) at a single tertiary care hospital. Patients were identified by ICD-9 codes: 995.92 for severe sepsis and 785.52 for septic shock; and had to have an echocardiogram within 48 h of ICU admission. Increased RV/LV was defined as RV/LV ≥ 0.9. Left and right-sided chamber dimensions were measured according to American Society of Echocardiography guidelines.

RESULTS

We included 146 consecutive ICU patients admitted with septic shock (72) or severe sepsis (74). There was no significant difference in ICU mortality in patients with RV/LV ≥ 0.9 versus RV/LV < 0.9 (p = .49).

CONCLUSIONS

An increased RV/LV does not predict mortality in severe sepsis or septic shock.

Pharmacokinetics of Continuous Infusion Beta-lactams in the Treatment of Acute Pulmonary Exacerbations in Adult Patients With Cystic Fibrosis

BACKGROUND

Several clinical trials have shown the efficacy of continuous infusion beta-lactam (BL) antibiotics in patients with cystic fibrosis (CF); however, little is known about pharmacokinetic changes during the treatment of an acute pulmonary exacerbation (APE). Identifying and understanding these changes may assist in optimizing antibiotic dosing during APE treatment.

METHODS

This study was a retrospective cohort study of 162 adult patients with CF admitted to the University of Utah Hospital between January 1, 2008, and May 15, 2014, for treatment of an APE with both a continuous infusion BL and IV tobramycin. We extracted the administered doses of continuous infusion BLs and tobramycin along with serum drug concentrations and calculated medication clearance rates. The primary outcome was change in clearance rates of continuous infusion BLs between day 2 and day 7 of APE treatment.

RESULTS

The BL clearance rate increased 20.7% (95% CI, 11.42 to 32.49; P < .001), whereas the tobramycin clearance rate decreased 6.3% (95% CI, -12.29 to -4.45; P < .001). The mean percent predicted FEV₁ increased between admission and discharge by 12.2% (95% CI, -13.81 to -10.55; P < .001).

CONCLUSIONS

Clinicians should monitor BL levels along with aminoglycoside levels and make dose adjustments to maximize the chance of optimal antibiotic treatment. Continuous infusion BL and tobramycin clearance can change dramatically during the treatment of an APE, which may necessitate significant changes in dosing to achieve optimal antibiotic levels. Clearance rates of these antibiotics may change in opposite directions, requiring specific monitoring of each medication.

Sleep Phase Delay in Cystic Fibrosis: A Potential New Manifestation of Cystic Fibrosis Transmembrane Regulator Dysfunction

BACKGROUND

Cystic fibrosis (CF) transmembrane regulator (CFTR) protein dysfunction causes CF. Improving survival allows detection of increasingly subtle disease manifestations. CFTR dysfunction in the central nervous system (CNS) may disturb circadian rhythm and thus sleep phase. We studied sleep in adults to better understand potential CNS CFTR dysfunction.

METHODS

We recruited participants from April 2012 through April 2015 and administered the Munich Chronotype Questionnaire (MCTQ). We compared free-day sleep measurements between CF and non-CF participants and investigated associations with CF survival predictors.

RESULTS

We recruited 23 female and 22 male adults with CF aged 18 to 46 years and 26 female and 22 male volunteers aged 18 to 45 years. Compared with volunteers without CF, patients with CF had delayed sleep onset (0.612 h; P = .015), midsleep (1.11 h; P < .001), and wake (1.15 h; P < .001) times and prolonged sleep latency (7.21 min; P = .05) and duration (0.489 h; P = .05). Every hour delay in sleep onset was associated with shorter sleep duration by 0.29 h in patients with CF and 0.75 h in subjects without CF (P = .007) and longer sleep latency by 7.51 min in patients with CF and 1.6 min in volunteers without CF (P = .035). Among patients with CF, FEV₁ % predicted, prior acute pulmonary exacerbations, and weight were independent of all free-day sleep measurements.

CONCLUSIONS

CF in adults is associated with marked delays in sleep phase consistent with circadian rhythm phase delays. Independence from disease characteristics predictive of survival suggests that sleep phase delay is a primary manifestation of CFTR dysfunction in the CNS.

Improving performance in the detection and management of cystic fibrosis-related diabetes in the Mountain West Cystic Fibrosis Consortium

OBJECTIVE

Cystic fibrosis (CF)-related diabetes (CFRD) is associated with increased morbidity and mortality. Improved detection and management may improve outcomes; however, actual practice falls short of published guidelines. We studied efforts to improve CFRD screening and management in the Mountain West CF Consortium (MWCFC).

RESEARCH DESIGN AND METHODS

This is a prospective observational cohort study evaluating quality improvement by accredited CF centers in Arizona, Colorado, New Mexico, and Utah performed between 2002 and 2008. After Institutional Review Board (IRB) approval, centers evaluated adherence with CF Foundation guidelines for CFRD. Each center developed and implemented quality improvement plans to improve both screening and management. Centers were reassessed 1 year later.

RESULTS

Initially, each CF center had low adherence with screening recommendations (26.5% of eligible patients) that did not improve during the study. However, patients with confirmed CFRD markedly increased (141 (12% of MWCFC patients) to 224 (17%), p<0.001), and with improved adherence to management guidelines, patients with CFRD had increased weight (56.8-58.9 kg, p<0.001), body mass index (21.1-21.4, p=0.003), and weight-for-age z-score (-1.42 to -0.84, p<0.001). Quality improvement methods were specific to the practice settings of each center but shared the common goal of adhering to CFRD care guidelines. 1 year after implementation, no center significantly differed from any other in level of adherence to guidelines.

CONCLUSIONS

Improving adherence with CFRD care guidelines requires substantial effort and may be incompletely successful, particularly for CFRD screening, but the effort may significantly improve patient monitoring and clinically relevant outcomes such as weight.

Rib plating of acute and sub-acute non-union rib fractures in an adult with cystic fibrosis: a case report

Background

Rib fractures associated with osteoporosis have been reported to occur ten times more frequently in adults with cystic fibrosis. Fractures cause chest pain, and interfere with cough and sputum clearance leading to worsened lung function and acute exacerbations which are the two main contributors to early mortality in cystic fibrosis. Usual treatment involves analgesics and time for healing; however considerable pain and disability result due to constant re-injury from chronic repetitive cough. Recently, surgical plating of rib fractures has become commonplace in treating acute, traumatic chest injuries. We describe here successful surgical plating in a White cystic fibrosis patient with multiple, non-traumatic rib fractures.

Case presentation

A-37-year old White male with cystic fibrosis was readmitted to Intermountain Medical Center for a pulmonary exacerbation. He had developed localized rib pain while coughing 2 months earlier, with worsening just prior to hospital admission in conjunction with a “pop” in the same location while bending over. A chest computerized tomography scan at admission demonstrated an acute 5th rib fracture and chronic non-united 6th and 7th right rib fractures. An epidural catheter was placed both for analgesia and to make secretion clearance possible in preparation for the surgery performed 2 days later. Under general anesthesia, he had open reduction and internal fixation of the right 5th, 6th and 7th rib fractures with a Synthes Matrix rib set. After several days of increased oxygen requirements, fever, fluid retention, and borderline vital signs, he stabilized. Numerical pain rating scores from his ribs were lower post-operatively and he was able to tolerate chest physical therapy and vigorous coughing.

Conclusions

In our case report, rib plating with bone grafting improved rib pain and allowed healing of the fractures and recovery, although the immediate post-op period required close attention and care. We believe repair may be of benefit in selected cystic fibrosis patients, such as our patient who had suffered multiple rib fractures that were healing poorly.

Ivacaftor in subjects with cystic fibrosis who are homozygous for the F508del-CFTR mutation

BACKGROUND

Ivacaftor (VX-770) is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that was approved in the United States for the treatment of cystic fibrosis (CF) in patients ≥ 6 years of age who have a G551D mutation; however, the most prevalent disease-causing CFTR mutation, F508del, causes a different functional defect. The objectives of this study were to evaluate the safety of ivacaftor in a larger population and for a longer time period than tested previously and to assess the efficacy of ivacaftor in subjects with CF who are homozygous for F508del-CFTR.

METHODS

This was a phase 2 study with a 16-week randomized (4:1), double-blind, placebo-controlled period (part A) and an open-label extension (part B) for subjects who met prespecified criteria.

RESULTS

Part A: The safety profile of ivacaftor was comparable to that of the placebo. The overall adverse event frequency was similar in the ivacaftor (87.5%) and placebo (89.3%) groups through 16 weeks. The difference in the change of FEV₁ % predicted from baseline through week 16 (primary end point) between the ivacaftor and placebo groups was 1.7% (P = .15). Sweat chloride, a biomarker of CFTR activity, showed a small reduction in the ivacaftor vs placebo groups of -2.9 mmol/L (P = .04) from baseline through week 16. Part B: No new safety signals were identified. The changes in FEV₁ or sweat chloride in part A were not sustained with ivacaftor treatment from week 16 to week 40.

CONCLUSIONS

These results expand the safety information for ivacaftor and support its continued evaluation. Lack of a clinical effect suggests that a CFTR potentiator alone is not an effective therapeutic approach for patients who have CF and are homozygous for F508del-CFTR.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00953706; URL: www.clinicaltrials.gov.

Toxicity effects of short term diesel exhaust particles exposure to human small airway epithelial cells (SAECs) and human lung carcinoma epithelial cells (A549)

In this study, confocal Raman spectroscopy, atomic force microscope (AFM) and multiplex ELISA were applied to analyze the biophysical responses (biomechanics and biospectroscopy) of normal human primary small airway epithelial cells (SAECs) and human lung carcinoma epithelial A549 cells to in vitro short term DEP exposure (up to 2h). Raman spectra revealed the specific cellular biomolecular changes in cells induced by DEP compared to unexposed control cells. Principal component analysis was successfully applied to analyze spectral differences between control and treated groups from multiple individual cells, and indicated that cell nuclei are more sensitive than other cell locations. AFM measurements indicated that 2h of DEP exposure induced a significant decrease in cell elasticity and a dramatic change in membrane surface adhesion force. Cytokine and chemokine production measured by multiplex ELISA demonstrated DEP-induced inflammatory responses in both cell types.

Delay in recognition of pulmonary arterial hypertension: factors identified from the REVEAL Registry

BACKGROUND

Pulmonary arterial hypertension (PAH) is a progressive and fatal disorder. Despite the emergence of effective therapy, PAH is commonly at an advanced stage when recognized. Factors associated with a prolonged symptomatic period before the recognition of PAH have not been fully evaluated.

METHODS

The Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL Registry) enrolled 2,967 US adult patients with PAH from March 2006 to September 2007. Patients were considered to have delayed disease recognition if > 2 years elapsed between symptom onset and the patient receiving a PAH diagnosis, starting on PAH-specific therapy, or receiving a diagnosis by right-sided heart catheterization.

RESULTS

In 21.1% of patients, symptoms were experienced for > 2 years before PAH was recognized. Patients with onset of PAH symptoms before age 36 years showed the highest likelihood of delayed disease recognition (OR, 3.07; 95% CI, 2.03-4.66). History of obstructive airways disease (OR, 1.93; 95% CI, 1.5-2.47) and sleep apnea (OR, 1.72; 95% CI, 1.33-2.22) were independently associated with delayed PAH recognition. Six-minute walk distance < 250 m (OR, 1.91; 95% CI, 1.16-3.13), right atrial pressure < 10 mm Hg (OR, 1.77; 95% CI, 1.26-2.48), and pulmonary vascular resistance < 10 Wood units (OR, 1.28; 95% CI, 1.02-1.60) were also associated with delayed disease recognition, but sex, race/ethnicity, and geographic region showed no association.

CONCLUSIONS

One in five patients in the REVEAL Registry who were diagnosed with PAH reported symptoms for > 2 years before their disease was recognized. Younger individuals and patients with histories of common respiratory disorders were most likely to experience delayed PAH recognition.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00370214; URL: www.clinicaltrials.gov.

Predicting survival in pulmonary arterial hypertension: insights from the Registry to Evaluate Early and Long-Term Pulmonary Arterial Hypertension Disease Management (REVEAL)

BACKGROUND

Factors that determine survival in pulmonary arterial hypertension (PAH) drive clinical management. A quantitative survival prediction tool has not been established for research or clinical use.

METHODS AND RESULTS

Data from 2716 patients with PAH enrolled consecutively in the US Registry to Evaluate Early and Long-Term PAH Disease Management (REVEAL) were analyzed to assess predictors of 1-year survival. We identified independent prognosticators of survival and derived a multivariable, weighted risk formula for clinical use. One-year survival from the date of enrollment was 91.0% (95% confidence interval [CI], 89.9 to 92.1). In a multivariable analysis with Cox proportional hazards, variables independently associated with increased mortality included pulmonary vascular resistance >32 Wood units (hazard ratio [HR], 4.1; 95% CI, 2.0 to 8.3), PAH associated with portal hypertension (HR, 3.6; 95% CI, 2.4 to 5.4), modified New York Heart Association/World Health Organization functional class IV (HR, 3.1; 95% CI, 2.2 to 4.4), men >60 years of age (HR, 2.2; 95% CI, 1.6 to 3.0), and family history of PAH (HR, 2.2; 95% CI, 1.2 to 4.0). Renal insufficiency, PAH associated with connective tissue disease, functional class III, mean right atrial pressure, resting systolic blood pressure and heart rate, 6-minute walk distance, brain natriuretic peptide, percent predicted carbon monoxide diffusing capacity, and pericardial effusion on echocardiogram all predicted mortality. Based on these multivariable analyses, a prognostic equation was derived and validated by bootstrapping technique.

CONCLUSIONS

We identified key predictors of survival based on the patient's most recent evaluation and formulated a contemporary prognostic equation. Use of this tool may allow the individualization and optimization of therapeutic strategies. Serial follow-up and reassessment are warranted. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00370214.

Year-to-year changes in lung function in individuals with cystic fibrosis

BACKGROUND

We examined the year-to-year change in FEV(1) for individuals and the overall cystic fibrosis population to better understand how individual trends may differ from population trends.

METHODS

We calculated individual yearly changes using the largest annual FEV(1) percent predicted (FEV(1)%) measurement in 20,644 patients (6-45years old) included in the Epidemiologic Study of Cystic Fibrosis. We calculated yearly population changes using age-specific medians.

RESULTS

FEV(1)% predicted decreased 1-3 points per year for individuals, with maximal decreases in 14-15year olds. Population changes agreed with individual changes up to age 15; however after age 30, yearly population change approximated zero while individual FEV(1)% predicted decreases were 1-2 points per year.

CONCLUSIONS

Adolescents have the greatest FEV(1)% predicted decreases; however, loss of FEV(1) is a persistent risk in 6-45year old CF patients. Recognizing individual year-to-year changes may improve patient-specific care and may suggest new methods for measuring program quality.

Lung transplantation for cystic fibrosis

Lung transplantation is a complex, high-risk, potentially life-saving therapy for the end-stage lung disease of cystic fibrosis (CF). The decision to pursue transplantation involves comparing the likelihood of survival with and without transplantation as well as assessing the effect of wait-listing and transplantation on the patient's quality of life. Although recent population-based analyses of the US lung allocation system for the CF population have raised controversies about the survival benefits of transplantation, studies from the United Kingdom and Canada have suggested a definite survival advantage for those receiving transplants. In response to these and other controversies, leaders in transplantation and CF met together in Lansdowne, Virginia, to consider the state of the art in lung transplantation for CF in an international context, focusing on advances in surgical technique, measurement of outcomes, use of prognostic criteria, variations in local control over listing, and prioritization among the United States, Canada, the United Kingdom, and The Netherlands, patient adherence before and after transplantation and other issues in the broader context of lung transplantation. Finally, the conference members carefully considered how efforts to improve outcomes for lung transplantation for CF lung disease might best be studied. This Roundtable seeks to communicate the substance of our discussions.

Insulin therapy to improve BMI in cystic fibrosis-related diabetes without fasting hyperglycemia: results of the cystic fibrosis related diabetes therapy trial

OBJECTIVE

Cystic fibrosis-related diabetes (CFRD) without fasting hyperglycemia (CFRD FH-) is not associated with microvascular or macrovascular complications, leading to controversy about the need for treatment. The Cystic Fibrosis Related Diabetes Therapy (CFRDT) Trial sought to determine whether diabetes therapy improves BMI in these patients.

RESEARCH DESIGN AND METHODS

A three-arm multicenter randomized trial compared 1 year of therapy with premeal insulin aspart, repaglinide, or oral placebo in subjects with cystic fibrosis who had abnormal glucose tolerance.

RESULTS

One hundred adult patients were enrolled. Eighty-one completed the study, including 61 with CFRD FH- and 20 with severly impaired glucose tolerance (IGT). During the year before therapy, BMI declined in all groups. Among the group with CFRD FH-, insulin-treated patients lost 0.30 +/- 0.21 BMI units the year before therapy. After 1 year of insulin therapy, this pattern reversed, and they gained 0.39 +/- 21 BMI units (P = 0.02). No significant change in the rate of BMI decline was seen in placebo-treated patients (P = 0.45). Repaglinide-treated patients had an initial significant BMI gain (0.53 +/- 0.19 BMI units, P = 0.01), but this effect was not sustained. After 6 months of therapy they lost weight so that by 12 months there was no difference in the rate of BMI change during the study year compared with the year before (P = 0.33). Among patients with IGT, neither insulin nor repaglinide affected the rate of BMI decline. No significant differences were seen in the rate of lung function decline or the number of hospitalizations in any group.

CONCLUSIONS

Insulin therapy safely reversed chronic weight loss in patients with CFRD FH-.

Measurement of lung volumes

Lung volume measurements always determine total lung capacity (TLC), and most measurement techniques also determine functional residual capacity (FRC) and residual volume (RV). These measurements are needed less often than spirometry-derived values and require somewhat more difficult methods than required by spirometry. As with spirometry, accurate interpretation relies on appropriate reference values, standardized methodology and technically well-performed testing. A reduction in TLC defines chest restriction. Increases in TLC, FRC and RV are often seen in patients with airway obstruction. Patients with mixed restrictive and obstructive disease may have spirometry results that are difficult to interpret, and it is in these patients that lung volume measurements may be especially helpful.

Design of the REVEAL registry for US patients with pulmonary arterial hypertension

The Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL) has been designed to meet the need for current information about patients with pulmonary arterial hypertension (PAH). The main objectives of REVEAL are to better define and understand PAH and to assess the consequences of treatment strategies. REVEAL is collecting clinically relevant data from 3500 consecutively enrolled patients with confirmed PAH diagnoses. Outcomes will be evaluated longitudinally and compared according to the baseline classification of PAH. The primary outcome for group comparisons will be survival. Collected data include World Health Organization functional class, 6-minute walk distance, cardiopulmonary exercise testing, pulmonary function test results, hemodynamic measurements, functional status, hospitalizations, and death. REVEAL will be the richest source of data on patients with World Health Organization group I PAH.

Lung Transplantation and Survival in Children with Cystic Fibrosis

BACKGROUND

The effects of lung transplantation on the survival and quality of life in children with cystic fibrosis are uncertain.

METHODS

We used data from the U.S. Cystic Fibrosis Foundation Patient Registry and from the Organ Procurement and Transplantation Network to identify children with cystic fibrosis who were on the waiting list for lung transplantation during the period from 1992 through 2002. We performed proportional-hazards survival modeling, using multiple clinically relevant covariates that were available before the children were on the waiting list and the interactions of these covariates with lung transplantation as a time-dependent covariate. The data were insufficient in quality and quantity for a retrospective quality-of-life analysis.

RESULTS

A total of 248 of the 514 children on the waiting list underwent lung transplantation in the United States during the period from 1992 through 2002. Proportional-hazards modeling identified four variables besides transplantation that were associated with changes in survival. Burkholderia cepacia infection was associated with a trend toward decreased survival, regardless of whether the patient underwent transplantation. A diagnosis of diabetes before the patient was placed on the waiting list decreased survival while the patient was on the waiting list but did not decrease survival after transplantation, whereas older age did not affect waiting-list survival but decreased post-transplantation survival. Staphylococcus aureus infection increased waiting-list survival but decreased post-transplantation survival. Using age, diabetes status, and S. aureus infection status as covariates, we estimated the effect of transplantation on survival for each patient group, expressed as a hazard factor of less than 1 for a benefit and more than 1 for a risk of harm. Five patients had a significant estimated benefit, 283 patients had a significant risk of harm, 102 patients had an insignificant benefit, and 124 patients had an insignificant risk of harm associated with lung transplantation.

CONCLUSIONS

Our analyses estimated clearly improved survival for only 5 of 514 patients on the waiting list for lung transplantation. Prolongation of life by means of lung transplantation should not be expected in children with cystic fibrosis. A prospective, randomized trial is needed to clarify whether and when patients derive a survival and quality-of-life benefit from lung transplantation.

A phase 2 study of aztreonam lysine for inhalation to treat patients with cystic fibrosis and Pseudomonas aeruginosa infection

BACKGROUND

Aztreonam lysine for inhalation (AZLI) is being developed for treatment of CF patients with Pseudomonas aeruginosa airway infection.

METHODS

This double-blind, randomized, placebo-controlled Phase 2 study evaluated the safety, tolerability and efficacy of 75 and 225 mg AZLI administered BID for 14 days using the eFlow Electronic Nebulizer (Pari Innovative Manufacturers, Inc., Midlothian, VA). Patients were 13 years and older with FEV1>or=40% predicted, chronic P. aeruginosa infection, and had used no anti-pseudomonal antibiotics for 56 days.

RESULTS

Of 131 patients screened, 105 received AZLI or placebo. Mean age was 26 years and mean FEV1 percent predicted was 77% at baseline. There was a statistically significant reduction, compared to placebo, in P. aeruginosa CFU density in each AZLI group at Days 7 and 14 (P<0.001). The planned primary analysis, percent change in FEV1 at Day 14, demonstrated no statistically significant difference. Post hoc analysis demonstrated significant increase in FEV1 at Day 7 for the subset of patients with baseline FEV1<75% predicted in the 225 mg AZLI group. Bronchodilator use was associated with greater improvement in FEV1, as well as greater reduction in P. aeruginosa bacterial density and higher plasma aztreonam concentrations in the 225 mg AZLI group. Adverse events were similar between placebo and AZLI although there was a trend toward increased respiratory symptoms in the 225 mg AZLI group.

CONCLUSION

These data support the further development of AZLI and provide information for the design of subsequent studies.

Lung transplantation and survival in children with cystic fibrosis

BACKGROUND

The effects of lung transplantation on the survival and quality of life in children with cystic fibrosis are uncertain.

METHODS

We used data from the U.S. Cystic Fibrosis Foundation Patient Registry and from the Organ Procurement and Transplantation Network to identify children with cystic fibrosis who were on the waiting list for lung transplantation during the period from 1992 through 2002. We performed proportional-hazards survival modeling, using multiple clinically relevant covariates that were available before the children were on the waiting list and the interactions of these covariates with lung transplantation as a time-dependent covariate. The data were insufficient in quality and quantity for a retrospective quality-of-life analysis.

RESULTS

A total of 248 of the 514 children on the waiting list underwent lung transplantation in the United States during the period from 1992 through 2002. Proportional-hazards modeling identified four variables besides transplantation that were associated with changes in survival. Burkholderia cepacia infection was associated with a trend toward decreased survival, regardless of whether the patient underwent transplantation [corrected]. A diagnosis of diabetes before the patient was placed on the waiting list decreased survival while the patient was on the waiting list but did not decrease survival after transplantation, whereas older age did not affect waiting-list survival but decreased post-transplantation survival. Staphylococcus aureus infection increased waiting-list survival but decreased post-transplantation survival. Using age, diabetes status, and S. aureus infection status as covariates, we estimated the effect of transplantation on survival for each patient group, expressed as a hazard factor of less than 1 for a benefit and more than 1 for a risk of harm. Five patients had a significant estimated benefit, 283 patients had a significant risk of harm, 102 patients had an insignificant benefit, and 124 patients had an insignificant risk of harm associated with lung transplantation [corrected].

CONCLUSIONS

Our analyses estimated clearly improved survival for only 5 of 514 patients on the waiting list for lung transplantation. Prolongation of life by means of lung transplantation should not be expected in children with cystic fibrosis. A prospective, randomized trial is needed to clarify whether and when patients derive a survival and quality-of-life benefit from lung transplantation.