Continuous glucose monitoring and advanced glycation endproducts for prediction of clinical outcomes and development of cystic fibrosis-related diabetes in adults with CF.

Introductions: Cystic fibrosis-related diabetes (CFRD) is associated with pulmonary decline, compromised nutritional status, and earlier mortality. Onset is often insidious, so screening for early detection of glycemic abnormalities is important. Continuous glucose monitoring (CGM) has been validated in people with CF and has been shown to detect early glycemic variability otherwise missed on 2-hour oral glucose tolerance testing (OGTT). We previously reported that CGM measures of hyperglycemia and glycemic variability are superior to hemoglobin A1c (HbA1c) in distinguishing those with and without CFRD. However, little is known about the long-term predictive value of CGM measures of glycemia for both the development of CFRD and their effect on key clinical outcomes such as weight maintenance and pulmonary function. In addition, there have been no studies investigating advanced glycation endproducts (AGE) assessed by skin autofluorescence in people with CF. Methods: In this prospective observational study, CGM and HbA1c were measured at 2 to 3 time points 3 months apart in 77 adults with CF. Participants who did not have CFRD at the time of enrollment underwent OGTT at the baseline visit, and all participants had AGE readings at baseline. Follow up data including anthropometric measures, pulmonary function and CFRD status were collected by review of medical records 1- and 2-years after the baseline visits. We applied multivariable linear regression models correlating glycemic measures to change in key clinical outcomes (weight, BMI, FEV1) accounting for age, gender and elexacaftor/tezacaftor/ivacaftor (ETI) use. We also conducted logistic regression analyses comparing baseline glycemic data to development of CFRD during the 2-year follow up period. Results: Of the 77 participants, 25 had pre-existing CFRD at the time of enrollment, and six participants were diagnosed with CFRD by the OGTT performed at the baseline visit. When adjusting for age, gender, and ETI use, multiple CGM measures correlated with weight and BMI decline after one year but not after two years. CGM and HbA1c at baseline did not predict decline in FEV1 (p>0.05 for all). In the 46 participants without a diagnosis of CFRD at baseline, two participants were diagnosed with CFRD over the following two years, but CGM measures at baseline did not predict progression to CFRD. Baseline AGE values were higher in individuals with CFRD and correlated with multiple measures of dysglycemia (HbA1c, AG, SD, CV, TIR, % time >140, >180, >250) as well as weight. AGE values also correlated with FEV1 decline at year 1 and weight decline at year 1 and year 2. Conclusions: Several key CGM measures of hyperglycemia and glycemic variability were predictive of future decline in weight and BMI over one year in this population of adults with CF with and without CFRD. None of the baseline glycemic variables predicted progression to CFRD over 2 years. To our knowledge, this is the first report correlating AGE levels with key clinical and glycemic measures in CF. Limitations of these analyses include the small number of participants who developed CFRD (n=2) during the follow up period and the initiation of ETI by many participants, affecting their trajectory in weight and pulmonary function. These results provide additional data supporting the potential role for CGM in identifying clinically significant dysglycemia in CF. Future studies are needed to investigate CGM as a diagnostic and screening tool for CFRD and to understand the implications of AGE measures in this patient population.

Continuous Glucose Monitoring and HbA1c in Cystic Fibrosis: Clinical Correlations and Implications for CFRD Diagnosis.

CONTEXT: The clinical utility and implications of continuous glucose monitoring (CGM) in cystic fibrosis (CF) are unclear. OBJECTIVE: We examined the correlation between CGM measures and clinical outcomes in adults with CF, investigated the relationship between hemoglobin A1c (HbA1c) and CGM-derived average glucose (AG), and explored CGM measures that distinguish cystic fibrosis-related diabetes (CFRD) from normal and abnormal glucose tolerance. METHODS: This prospective observational study included 77 adults with CF who had CGM and HbA1c measured at 2 to 3 time points 3 months apart. RESULTS: Thirty-one of the 77 participants met American Diabetes Association-recommended diagnostic criteria for CFRD by oral glucose tolerance testing and/or HbA1c. In all participants, CGM measures of hyperglycemia and glycemic variability correlated with nutritional status and pulmonary function. HbA1c was correlated with AG (R2 = 0.71, P < 0.001), with no significant difference between this regression line and that previously established in type 1 and type 2 diabetes and healthy volunteers. Cutoffs of 17.5% time > 140 mg/dL and 3.4% time > 180 mg/dL had sensitivities of 87% and 90%, respectively, and specificities of 95%, for identifying CFRD. Area under the curve and percent of participants correctly classified with CFRD were higher for AG, SD, % time > 140, > 180, and > 250 mg/dL than for HbA1c. CONCLUSION: CGM measures of hyperglycemia and glycemic variability are superior to HbA1c in distinguishing those with and without CFRD. CGM-derived AG is strongly correlated with HbA1c in adults with CF, with a similar relationship to other diabetes populations. Future studies are needed to investigate CGM as a diagnostic and screening tool for CFRD.

Supplemental Oxygen Alters the Airway Microbiome in Cystic Fibrosis.

Features of the airway microbiome in persons with cystic fibrosis (pwCF) are correlated with disease progression. Microbes have traditionally been classified for their ability to tolerate oxygen. It is unknown whether supplemental oxygen, a common medical intervention, affects the airway microbiome of pwCF. We hypothesized that hyperoxia significantly impacts the pulmonary microbiome in cystic fibrosis. In this study, we cultured spontaneously expectorated sputum from pwCF in artificial sputum medium under 21%, 50%, and 100% oxygen conditions using a previously validated model system that recapitulates microbial community composition in uncultured sputum. Culture aliquots taken at 24, 48, and 72 h, along with uncultured sputum, underwent shotgun metagenomic sequencing with absolute abundance values obtained with the use of spike-in bacteria. Raw sequencing files were processed using the bioBakery pipeline to determine changes in taxonomy, predicted function, antimicrobial resistance genes, and mobile genetic elements. Hyperoxia reduced absolute microbial load, species richness, and diversity. Hyperoxia reduced absolute abundance of specific microbes, including facultative anaerobes such as Rothia and some Streptococcus species, with minimal impact on canonical CF pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. The effect size of hyperoxia on predicted functional pathways was stronger than that on taxonomy. Large changes in microbial cooccurrence networks were noted. Hyperoxia exposure perturbs airway microbial communities in a manner well tolerated by key pathogens. Supplemental oxygen use may enable the growth of lung pathogens and should be further studied in the clinical setting. IMPORTANCE The airway microbiome in persons with cystic fibrosis (pwCF) is correlated with lung function and disease severity. Supplemental oxygen use is common in more advanced CF, yet its role in perturbing airway microbial communities is unknown. By culturing sputum samples from pwCF under normal and elevated oxygen conditions, we found that increased oxygen led to reduced total numbers and diversity of microbes, with relative sparing of common CF pathogens such as Pseudomonas aeruginosa and Staphylococcus aureus. Supplemental oxygen use may enable the growth of lung pathogens and should be further studied in the clinical setting.

The Effects of Ivacaftor on Bone Density and Microarchitecture in Children and Adults with Cystic Fibrosis.

CONTEXT: Cystic fibrosis (CF) transmembrane conductance (CFTR) dysfunction may play a role in CF-related bone disease (CFBD). Ivacaftor is a CFTR potentiator effective in improving pulmonary and nutritional outcomes in patients with the G551D-CFTR mutation. The effects of ivacaftor on bone health are unknown. OBJECTIVE: To determine the impact of ivacaftor on bone density and microarchitecture in children and adults with CF. DESIGN: Prospective observational multiple cohort study. SETTING: Outpatient clinical research center within a tertiary academic medical center. PATIENTS OR OTHER PARTICIPANTS: Three cohorts of age-, race-, and gender-matched subjects were enrolled: 26 subjects (15 adults and 11 children) with CF and the G551D-CFTR mutation who were planning to start or had started treatment with ivacaftor within 3 months (Ivacaftor cohort), 26 subjects with CF were not treated with ivacaftor (CF Control cohort), and 26 healthy volunteers. INTERVENTIONS: All treatments, including Ivacaftor, were managed by the subjects' pulmonologists. MAIN OUTCOME MEASURES: Bone microarchitecture by high-resolution peripheral quantitative computed tomography (HR-pQCT), areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) and bone turnover markers at baseline, 1, and 2 years. RESULTS: Cortical volume, area, and porosity at the radius and tibia increased significantly in adults in the Ivacaftor cohort. No significant differences were observed in changes in aBMD, trabecular microarchitecture, or estimated bone strength in adults or in any outcome measures in children. CONCLUSIONS: Treatment with ivacaftor was associated with increases in cortical microarchitecture in adults with CF. Further studies are needed to understand the implications of these findings.

An official American Thoracic Society Policy statement: managing conflict of interest in professional societies.

BACKGROUND: Competing interests occur frequently in health care. This results in the potential for conflict of interest (COI). COI can lead to biased generation or assessment of evidence and misinform healthcare decision makers. Declaration of COI is insufficient to neutralize potentially harmful effects. Medical professional societies are obliged to develop robust mechanisms to "manage" COI, particularly in the development of official guidance documents that affect health care. PURPOSE: This document describes the background, methods, and content of the new "American Thoracic Society (ATS) Policy on Management of COI in Official ATS Documents, Projects, and Conferences." METHODS: We used existing reviews on COI policies that were prepared for the World Health Organization and for an ATS guideline methodology workshop as the evidence base for this work. We reviewed existing policies of selected organizations and other relevant literature. Members of the ATS Documents Development and Implementation Committee and the ATS Ethics and COI Committee collaborated to draft a COI policy. We used face-to-face meetings, electronic correspondence, and teleconferences to finalize the draft. The policy then underwent review and ultimate approval by the ATS Board of Directors. RESULTS: The ATS developed a new policy and procedures for declaration and management of COI. These procedures include: (1) self declaration of COI, (2) review of potential participants' COI, (3) disclosure of COI to project participants, (4) refusal or excusal from certain decisions or recommendations when appropriate, (5) disclosure of COI to users of documents or attendees of conferences, (6) handling disputes in COI resolution. This policy includes a tool that may be useful for supporting decision makers in management of COIs as they assess the value and relevance of conflicts. CONCLUSIONS: The ATS Policy on Management of COI in Official ATS Documents, Projects, and Conferences, in effect since March 2008, promises greater organizational transparency. Application and ongoing evaluation of the policy will give the ATS the opportunity to determine its usefulness in specific settings.

Effects of a primary palliative care intervention on quality of life and mental health in cystic fibrosis.

BACKGROUND: Despite the significant impact of chronic symptoms on quality of life with cystic fibrosis (CF), the role of palliative care in management of this disease is not well defined. The coping, goal assessment, and relief from evolving CF symptoms (CF-CARES) model is a primary palliative care intervention designed to provide chronic symptom management at all stages of the disease. The goal of this pilot study was to estimate the effectiveness of the CF-CARES intervention on improving chronic symptoms and quality of life for people living with CF. METHODS: A structured assessment was used to guide referral to supportive services intended to address burdensome symptoms. Follow-up assessments were performed approximately 3 and 6 months later. Longitudinal regression analyses of changes in symptoms and quality of life were performed for all participants regardless of utilization of supportive services. Subgroup analyses were performed for subjects participating in mental health and alternative health services. RESULTS: Forty-one subjects completed assessment and referral processes. The mean number of CF-associated symptoms decreased over time, as did respiratory symptom-related distress and depressive symptoms. Subjects utilizing alternative health services reported less psychological distress at follow-up. Among subjects with severe disease, mental health, and quality of life improved, especially for those using mental health services. CONCLUSIONS: The CF-CARES model resulted in significant mental health and quality-of-life benefits, suggesting the value of integrating symptom management interventions into routine CF care. Moreover, mental health services can play a key role in CF-specific primary palliative care, especially for those with advanced disease.

Celiac Disease in Patients with Cystic Fibrosis-Related Bone Disease.

Both cystic fibrosis (CF) and celiac disease can cause low bone mineral density (BMD) and fractures. Celiac disease may occur at a higher frequency in patients with CF than the general population, and symptoms of these conditions may overlap. We report on two patients presenting with CF-related bone disease in the past year who were subsequently found to have concurrent celiac disease. Because adherence to a gluten-free diet may improve BMD in patients with celiac disease, this could have important implications for treatment. Clinicians should consider screening for celiac disease in patients with CF who have low BMD, worsening BMD in the absence of other risk factors, and/or difficult to treat vitamin D deficiency.

Impact of CFTR Modulation on Intestinal pH, Motility, and Clinical Outcomes in Patients With Cystic Fibrosis and the G551D Mutation.

OBJECTIVES: A defect in bicarbonate secretion contributes to the pathophysiology of gastrointestinal complications in patients with cystic fibrosis (CF). We measured gastrointestinal pH, clinical outcomes, and intestinal transit profiles in patients with the G551D mutation before and after treatment with ivacaftor, a CF transmembrane regulator channel (CFTR) potentiator. METHODS: Observational studies of ivacaftor effectiveness were conducted in the United States and Canada. A subset of subjects ingested a wireless motility capsule (n=10) that measures in vivo pH, both before therapy with ivacaftor and 1 month after treatment; values obtained were compared for mean pH and area under the pH curve, and regional intestinal motility. We also queried subjects about abdominal pain and recorded body weight before and after treatment. RESULTS: One month after administering ivacaftor, a significant increase in mean pH was observed after gastric emptying (P<0.05). Area under the pH curve analyses indicate increased bicarbonate mass (P<0.05 for select 5 min intervals and all segments >30 min); mean weight gain was 1.1 kg (P=0.08). No difference in abdominal pain or regional transit times was seen. CONCLUSIONS: CFTR modulation improves the proximal small intestinal pH profile in patients with the G551D CFTR mutation and we observed clinically relevant, contemporaneous weight gain, although it did not reach statistical significance. These data provide in vivo evidence that CFTR is an important regulator of bicarbonate secretion, which may be a translational link between CFTR function and clinical improvement.

Development and evaluation of a palliative care curriculum for cystic fibrosis healthcare providers.

BACKGROUND: Primary palliative care refers to basic skills that all healthcare providers can employ to improve quality of life for patients at any stage of disease. Training in these core skills is not commonly provided to clinicians caring for cystic fibrosis (CF) patients. The objective of this study was to assess change in comfort with core skills among care team members after participation in CF-specific palliative care training focused on management of burdensome symptoms and difficult conversations. METHODS: A qualitative needs assessment was performed to inform the development of an 18-hour curriculum tailored to the chronicity and complexity of CF care. A 32-question pre- and post-course survey assessed CF provider comfort with the targeted palliative care skills in 5 domains using a 5-point Likert scale (1=very uncomfortable, 3=neutral, 5=very comfortable). RESULTS: Among course participants (n=16), mean overall comfort score increased by 0.9, from 3 (neutral) to 3.9 (comfortable) (p<0.001). Mean comfort level increased significantly (range 0.8 to 1.4) in each skill domain: use of supportive care resources, pain management, non-pain symptom management, communication, and psychosocial skills. CONCLUSIONS: CF-specific palliative care training was well received by participants and significantly improved self-assessed comfort with core skills.

Trends in bone mineral density in young adults with cystic fibrosis over a 15 year period.

BACKGROUND: Improvements in clinical care have led to increased life expectancy in patients with cystic fibrosis (CF) over the past several decades. Whether these improvements have had significant effects on bone health in patients with CF is unclear. METHODS: This is a cross-sectional study comparing clinical characteristics and bone mineral density (BMD) measured by dual energy X-ray absorptiometry (DXA) in adults with CF evaluated in 1995-1999 to age-, race-, and gender-matched patients with CF evaluated in 2011-2013 at the same center on calibrated DXA machines. RESULTS: The cohorts were similar in terms of age, BMI, pancreatic insufficiency, presence of F508del mutation, and reproductive history. In the most recent cohort, pulmonary function was superior, and fewer patients had vitamin D deficiency or secondary hyperparathyroidism. Areal BMD measures of the PA spine, lateral spine, and distal radius were similarly low in the two cohorts. CONCLUSIONS: Although pulmonary function and vitamin D status were better in patients in the present-day cohort, areal BMD of the spine was reduced in a significant number of patients and was no different in patients with CF today than in the late 1990s. Further attention to optimizing bone health may be necessary to prevent CF-related bone disease.

Compromised bone microarchitecture and estimated bone strength in young adults with cystic fibrosis.

CONTEXT: Young adults with cystic fibrosis (CF) are at risk for low bone density and fractures, but the underlying alterations in bone microarchitecture that may contribute to their increased fracture risk are currently unknown. OBJECTIVE: The main goal of this study was to use high-resolution peripheral quantitative computed tomography (HR-pQCT) to characterize the bone microarchitecture, volumetric bone mineral density (vBMD), and estimated strength of the radius and tibia in young adults with CF compared with healthy volunteers. DESIGN AND SETTING: This was a cross-sectional study at an outpatient clinical research center within a tertiary academic medical center. PARTICIPANTS: Thirty young adults with CF, 18 to 40 years of age, were evaluated and compared with 60 healthy volunteers matched by age (±2 years), gender, and race. MAIN OUTCOME MEASURES: The primary outcomes were HR-pQCT-derived cortical and trabecular vBMD, bone microarchitecture, and estimates of bone strength. RESULTS: At the radius and tibia, young adults with CF had smaller bone cross-sectional area and lower vBMD. Cortical and trabecular microarchitecture were compromised at both sites, most notably involving the trabecular bone of the tibia. These differences translated into lower estimated bone strength both at the radius and tibia. After accounting for body mass index differences, young adults with CF had lower bone area and estimated bone strength at the radius and had compromised trabecular microarchitecture and lower total and trabecular vBMD and estimated bone strength at the tibia. Alterations in trabecular bone density and microarchitecture and estimated strength measures of the tibia were also greater than expected based on dual-energy x-ray absorptiometry-derived areal BMD differences. CONCLUSIONS: Young adults with CF have compromised bone microarchitecture and lower estimated bone strength at both the radius and tibia, even after accounting for their smaller body size. These skeletal deficits likely explain the higher fracture risk observed in young adults with CF.

Generation of multipotent lung and airway progenitors from mouse ESCs and patient-specific cystic fibrosis iPSCs.

Deriving lung progenitors from patient-specific pluripotent cells is a key step in producing differentiated lung epithelium for disease modeling and transplantation. By mimicking the signaling events that occur during mouse lung development, we generated murine lung progenitors in a series of discrete steps. Definitive endoderm derived from mouse embryonic stem cells (ESCs) was converted into foregut endoderm, then into replicating Nkx2.1+ lung endoderm, and finally into multipotent embryonic lung progenitor and airway progenitor cells. We demonstrated that precisely-timed BMP, FGF, and WNT signaling are required for NKX2.1 induction. Mouse ESC-derived Nkx2.1+ progenitor cells formed respiratory epithelium (tracheospheres) when transplanted subcutaneously into mice. We then adapted this strategy to produce disease-specific lung progenitor cells from human Cystic Fibrosis induced pluripotent stem cells (iPSCs), creating a platform for dissecting human lung disease. These disease-specific human lung progenitors formed respiratory epithelium when subcutaneously engrafted into immunodeficient mice.