Standards of Care for Cystic Fibrosis ten years later

Cystic fibrosis in Europe: improved lung function and longevity - reasons for cautious optimism, but challenges remain

BACKGROUND

Prognosis and disease severity in cystic fibrosis (CF) are linked to declining lung function. To characterise lung function by the number of adults in countries with different levels of Gross National Income (GNI), data from the European Cystic Fibrosis Society Patient Registry were utilised.

METHODS

Annual data including age, forced expiratory volume in 1 s (FEV1), anthropometry, genotype, respiratory cultures and CF-related diabetes (CFRD) were retrieved between 2011 and 2021. All countries were stratified into GNI per capita to reflect differences within Europe.

RESULTS

A consistent improvement in FEV1 % pred and survival was observed among the 47 621 people with CF (pwCF), including subjects with chronic Pseudomonas aeruginosa infection, CFRD and/or undernutrition. Mean values of FEV1 % pred changed from 85% to 94.2% for children and from 63.6% to 74.7% for adults. FEV1 % pred further increased among those carrying the F508del mutation in 2021, when elexacaftor/tezacaftor/ivacaftor was available. The number of adult pwCF increased from 13 312 in 2011 to 21 168 in 2021, showing a 60% increase. PwCF living in European lower income countries did not demonstrate a significant annual increase in FEV1 % pred or in the number of adults.

CONCLUSION

This pan-European analysis demonstrates a consistent improvement in FEV1 % pred, number of adult pwCF and survival over the last decade only in European higher and middle income countries. Urgent action is needed in the lower income countries where such improvement was not observed. The notable improvement observed in pwCF carrying the F508del mutation emphasises the need to develop treatments for all CF mutations.

Treatable traits and challenges in the clinical management of non-tuberculous mycobacteria lung disease in people with cystic fibrosis

INTRODUCTION

Over the last ten years an increasing prevalence and incidence of non-tuberculous mycobacteria (NTM) has been reported among patients with cystic fibrosis (CF) Viviani (J Cyst Fibros, 15(5):619-623, 2016). NTM pulmonary disease has been associated with negative clinical outcomes and often requires pharmacological treatment. Although specific guidelines help clinicians in the process of diagnosis and clinical management, the focus on the multidimensional assessment of concomitant problems is still scarce.

MAIN BODY

This review aims to identify the treatable traits of NTM pulmonary disease in people with CF and discuss the importance of a multidisciplinary approach in order to detect and manage all the clinical and behavioral aspects of the disease. The multidisciplinary complexity of NTM pulmonary disease in CF requires careful management of respiratory and extra-respiratory, including control of comorbidities, drug interactions and behavioral factors as adherence to therapies.

CONCLUSIONS

The treatable trait strategy can help to optimize clinical management through systematic assessment of all the aspects of the disease, providing a holistic treatment for such a multi-systemic and complex condition.

Implementation of standardized cystic fibrosis care algorithm to improve the center data-quality improvement project international collaboration

BACKGROUND

A collaboration between the University of Michigan (U of M) Cystic Fibrosis Center (CFC) and Marmara University (MU) CFC was initiated to improve the health status of people with cystic fibrosis (pwCF) at MU through implementing Quality Improvement (QI) initiatives. The main aim was to improve lung function in children with FEV1pp <80. The secondary aim was to assess the changes in health related quality of life.

METHODS

Included in the project were pwCF who received cystic fibrosis (CF) care at the MU CFC and were 6-18 years of age with an FEV1pp <80. Flow charts were created and a standardized CF care algorithm was implemented. Weekly case review were done to develop individualized treatment plans. Appropriate intervention was applied and patient data were assessed at baseline, 3, 6, 9 and 12 months. The Cystic Fibrosis Revised Questionnaire (CFQ-R) was completed.

RESULTS

55 pwCF were included (mean age:11.8 ± 3.3 years). Mean FEV1pp (SD) at baseline, 6 and 12 month was 63.7 (14.6), 66.9 (16.6), 70.4 (19.2), respectively, with a relative increase of 5.0% in 6 months (p:0.002) and 10.5% in 12 months compared to baseline (p<0.001). Physical functioning, eating problems and respiratory symptoms domains of the CFQ-R questionnaire were improved at the end of the one year for 6-13 (p = 0.024, p = 0.009, p = 0.002) and 13-18 year olds (p = 0.013, p = 0.002, p = 0.038).

CONCLUSION

There was significant improvement in pwCF with FEV1<80%pp after implementing this QI project. The processes and assessments used can be adopted by other low-middle income countries to improve similar measures.

Patient care in cystic fibrosis centers: a real-world analysis in Brazil

OBJECTIVE

To analyze the characteristics of cystic fibrosis (CF) care centers (CFCCs) in Brazil.

METHODS

A questionnaire was sent to the coordinators of all 51 registered CFCCs between May and September of 2021.

RESULTS

The response rate was 100%. Southeastern Brazil is the region where most of the CFCCs in the country are located (21 centers; 41%), followed by the southern and northeastern regions (11 centers each; 21.5%), the central-western region (6; 12%), and the northern region (2; 4%). A total of 4,371 patients with CF were cared for in Brazil during the study period, ranging from 7 to 240 patients per center (mean, 86 patients/center; median, 75 patients/center); 2,197 patients (50%) were cared for in centers in the southeastern region of the country, particularly in the state of São Paulo (33%), the remaining patients being treated in southern Brazil (1,014 patients, 23%), northeastern Brazil (665 patients, 15%), central-western Brazil (354 patients, 8%), and northern Brazil (141 patients, 4%). Overall, 47 centers (92%) reported having an incomplete multidisciplinary team; 4 (8%) lacked essential team members; 6 (12%) lacked a physical therapist; 5 (10%) lacked a dietitian; 17 (33%) lacked outpatient nursing care; 13 (25%) lacked outpatient social work services; 14 (27%) lacked a psychologist; and 32 (63%) lacked a clinical pharmacist. Seven CFCCs (14%) in the northern and northeastern regions of Brazil reported that the quality of newborn screening for CF was poor. All centers reported having difficulties in accessing CF medications.

CONCLUSIONS

Brazilian CFCCs experience multiple problems, including inadequate staffing, infrastructure, testing, and medication supply. There is an urgent need to regulate the implementation of CF referral centers and an appropriate network structure for the diagnosis and follow-up of CF patients using optimal treatment recommendations.

Reclassifying inconclusive diagnosis after newborn screening for cystic fibrosis. Moving forward

BACKGROUND

Newborn screening for Cystic Fibrosis (CF) is associated with situations where the diagnosis of CF or CFTR related disorders (CFTR-RD) cannot be clearly ruled out.

MATERIALS/PATIENTS AND METHODS

We report a case series of 23 children with unconclusive diagnosis after newborn screening for CF and a mean follow-up of 7.7 years (4-13). Comprehensive investigations including whole CFTR gene sequencing, in vivo intestinal current measurement (ICM), nasal potential difference (NPD), and in vitro functional studies of variants of unknown significance, helped to reclassify the patients.

RESULTS

Extensive genetic testing identified, in trans with a CF causing mutation, variants with varying clinical consequences and 3 variants of unknown significance (VUS). Eighteen deep intronic variants were identified by deep resequencing of the whole CFTR gene in 13 patients and were finally considered as non-pathogenic. All patients had normal CFTR dependent chloride transport in ICM. NPD differentiated 3 different profiles: CF-like tracings qualifying the patients as CF, such as F508del/D1152H patients; normal responses, suggesting an extremely low likelihood of developing a CFTR-RD such as F508del/TG11T5 patients; partial CFTR dysfunction above 20% of the normal, highlighting a remaining risk of developing CFTR-RD such as F508del/F1052V patients. The 3 VUS were reclassified as variant with defective maturation (D537N), defective expression (T582I) or with no clinical consequence (M952T).

CONCLUSION

This study demonstrates the usefulness of combining genetic and functional investigations to assess the possibility of evolving to CF or CFTR-RD in babies with inconclusive diagnosis at neonatal screening.

[Evidence-based treatment of cystic fibrosis]

Mucoviscidosis (cystic fibrosis [CF]) is the most common autosomal recessive inherited multisystem disease with fatal outcome. It is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which lead to a dysfunctional chloride channel and a defective CFTR protein. As a consequence, retention of insufficiently hydrated mucus affects multiple essential organs, mainly the lungs and airways, pancreas, liver, biliary tract and intestines. This leads to inflammation and infection, fibrosis and progressive tissue destruction. Respiratory failure is the major cause of mortality; however, in the no more than 30 years since the molecular characterization of the basic CFTR defect causing CF, tremendous success has been made with respect to the long-term prognosis of people with CF. This improvement in the prognosis was achieved by the cooperative spirit and networking of the very active and international CF research community and by establishing a multidisciplinary clinical CF team that implements the existing evidence in various aspects of standardized care together with the CF patient. This narrative review article presents the evidence in selected aspects of CF treatment, with special consideration of the most recent development of highly effective CFTR modulator treatment. This treatment will soon become available for more than 90% of the global CF patients and transform the pathophysiology as well as the course of disease towards a treatable chronic condition in internal medicine.

Extent of rescue of F508del-CFTR function by VX-809 and VX-770 in human nasal epithelial cells correlates with SNP rs7512462 in SLC26A9 gene in F508del/F508del Cystic Fibrosis patients

BACKGROUND

We analyzed the CFTR response to VX-809/VX-770 drugs in conditionally reprogrammed cells (CRC) of human nasal epithelium (HNE) from F508del/F508del patients based on SNP rs7512462 in the Solute Carrier Family 26, Member 9 (SLC26A9; MIM: 608481) gene.

METHODS

The I_sc-eq measurements of primary nasal epithelial cells from F508del/F508del patients (n = 12) for CFTR function were performed in micro Ussing chambers and compared with non-CF controls (n = 2). Data were analyzed according to the rs7512462 genotype which were determined by real-time PCR.

RESULTS

The CRC-HNE cells from F508del/F508del patients evidenced high variability in the basal levels of CFTR function. Also, the rs7512462*C allele showed an increased basal CFTR function and higher responses to VX-809 + VX-770. The rs7512462*CC + CT genotypes together evidenced CFTR function levels of 14.89% relatively to wt/wt (rs7512462*CT alone-15.29%) i.e., almost double of rs7512462*TT (7.13%). Furthermore, sweat [Cl^-] and body mass index of patients also evidenced an association with the rs7512462 genotype.

CONCLUSION

The CFTR function can be performed in F508del/F508del patient-derived CRC-HNEs and its function and responses to VX-809 + VX-770 combination as well as clinical data, are all associated with the rs7512462 variant, which partially sheds light on the generally inter-individual phenotypic variability and in personalized responses to CFTR modulator drugs.

Evaluation of continuous constant current and continuous pulsed current in sweat induction for cystic fibrosis diagnosis

Background

The sweat test (ST) is the gold standard for the diagnosis of cystic fibrosis (CF). However, little is known about sweat induction using different types of currents and waves. In this context, our objective was to develop a device to induce sweat and compare the use of continuous constant current (CCC) and continuous pulsed current (CPC) in individuals with CF and healthy controls.

Methods

A prospective cross-sectional study with experimental intervention. The variables of gender, ethnicity, age, and body mass index (BMI) were considered. The method of Gibson and Cooke was used, and the following markers were evaluated: sweat weight, electrical impedance, sufficient sweat amount, and CF diagnosis. Triangular (TPC) or sinusoidal (SPC) pulsed current was applied to the right arm, and CCC was applied to the left arm.

Results

The study analyzed 260 individuals, 141/213 (54.2%) were female participants, 135/260 (51.9%) were Caucasians. The distribution of individuals by concentration of chloride at the ST was: (CF) 26/260 (10%); (borderlines) 109/260 (41.9%); (healthy) 97/260 (37.3%); (insufficient weight in sweat) 28/260 (10.8%). No association was observed between the sufficient sweat amount to perform the ST when we compared the currents. However, the SPC showed a higher amount of sweat weight. Using Bland and Altman plot considering the agreement between the sweat chloride values achieved from CPC [SPC and TPC] and CCC, there was no proportional bias and mean values are unrelated and only explain less than 8% of the variation. Moreover, TPC presented higher electrical impedance when compared with SPC and CCC. SPC presented lower electrical impedance and higher sweat weight than CCC. Male participants presented lower electrical impedance and higher sweat weight with CCC and TPC, and higher sweat weight with SPC.

Conclusions

The evaluated currents are safe and able to induce and produce sweat in sufficient quantities for the ST. SPC presented lower electrical impedance when compared with other currents. The use of SPC is recommended to induce sweat in patients with sweat problems. Finally, ethnicity, gender, age and BMI did not influence sweat induction at the ST, and no side effect was observed in our study.

Electronic supplementary material

The online version of this article (10.1186/s12890-018-0696-3) contains supplementary material, which is available to authorized users.

ECFS best practice guidelines: the 2018 revision

Developments in managing CF continue to drive dramatic improvements in survival. As newborn screening rolls-out across Europe, CF centres are increasingly caring for cohorts of patients who have minimal lung disease on diagnosis. With the introduction of mutation-specific therapies and the prospect of truly personalised medicine, patients have the potential to enjoy good quality of life in adulthood with ever-increasing life expectancy. The landmark Standards of Care published in 2005 set out what high quality CF care is and how it can be delivered throughout Europe. This underwent a fundamental re-write in 2014, resulting in three documents; center framework, quality management and best practice guidelines. This document is a revision of the latter, updating standards for best practice in key aspects of CF care, in the context of a fast-moving and dynamic field. In continuing to give a broad overview of the standards expected for newborn screening, diagnosis, preventative treatment of lung disease, nutrition, complications, transplant/end of life care and psychological support, this consensus on best practice is expected to prove useful to clinical teams both in countries where CF care is developing and those with established CF centres. The document is an ECFS product and endorsed by the CF Network in ERN LUNG and CF Europe.

Cystic fibrosis

Cystic fibrosis is a common life-limiting autosomal recessive genetic disorder, with highest prevalence in Europe, North America, and Australia. The disease is caused by mutation of a gene that encodes a chloride-conducting transmembrane channel called the cystic fibrosis transmembrane conductance regulator (CFTR), which regulates anion transport and mucociliary clearance in the airways. Functional failure of CFTR results in mucus retention and chronic infection and subsequently in local airway inflammation that is harmful to the lungs. CFTR dysfunction mainly affects epithelial cells, although there is evidence of a role in immune cells. Cystic fibrosis affects several body systems, and morbidity and mortality is mostly caused by bronchiectasis, small airways obstruction, and progressive respiratory impairment. Important comorbidities caused by epithelial cell dysfunction occur in the pancreas (malabsorption), liver (biliary cirrhosis), sweat glands (heat shock), and vas deferens (infertility). The development and delivery of drugs that improve the clearance of mucus from the lungs and treat the consequent infection, in combination with correction of pancreatic insufficiency and undernutrition by multidisciplinary teams, have resulted in remarkable improvements in quality of life and clinical outcomes in patients with cystic fibrosis, with median life expectancy now older than 40 years. Innovative and transformational therapies that target the basic defect in cystic fibrosis have recently been developed and are effective in improving lung function and reducing pulmonary exacerbations. Further small molecule and gene-based therapies are being developed to restore CFTR function; these therapies promise to be disease modifying and to improve the lives of people with cystic fibrosis.

Anxiety and depression in adults with cystic fibrosis: a comparison between patients and the general population in Sweden and three other European countries

BACKGROUND

Cystic fibrosis (CF) is the most common autosomal recessive life-shortening disease among Caucasians. Studies exploring the prevalence of anxiety and depression in adult CF patients are few, show inconsistent findings and rarely include comparisons with general populations. Prevalence and degree of anxiety and depression were investigated in adult CF patients in Sweden, Belgium, Germany and the UK, and compared to corresponding general population data.

METHODS

Adult non-transplanted CF patients from the three largest CF-centres (out of four) in Sweden (N = 129; Age range 18-70 years; 50 % women) completed the Hospital Anxiety and Depression Scale (HADS). Studies using HADS in adult CF populations in the UK, Germany, and Belgium were included, as well as HADS normative data from the corresponding general populations.

RESULTS

No elevated risk for anxiety and depression was found among the CF patients. However, a Country x Group interaction effect emerged; CF patients experienced a higher degree of anxiety than the general population in Sweden, but not in the other countries, though this finding did not remain significant in a logistic regression analysis. In Sweden the effect was limited to women. A Country x Group interaction effect was also found for Depression; CF patients experienced lower degree of depression than the general population in Sweden, Germany and the UK, but not in Belgium/Netherlands.

CONCLUSIONS

Contrary to earlier outcomes, the present results do not indicate any general elevated risk for anxiety and depression among CF patients. Anxiety was slightly higher in the Swedish CF population, compared to the general population; this finding was not seen in the other countries. Depression among CF patients was lower than or similar to that in the general populations in the studied countries.

High individuality of respiratory bacterial communities in a large cohort of adult cystic fibrosis patients under continuous antibiotic treatment

Background

Routine clinical diagnostics of CF patients focus only on a restricted set of well-known pathogenic species. Recent molecular studies suggest that infections could be polymicrobial with many bacteria not detected by culture-based diagnostics.

Methodology and Principal Findings

A large cohort of 56 adults with continuous antibiotic treatment was studied and different microbial diagnostic methods were compared, including culture-independent and culture-based bacterial diagnostics. A total of 72 sputum samples including longitudinal observations was analysed by 16S rRNA gene sequence comparison. Prevalence of known pathogens was highly similar among all methods but the vast spectrum of bacteria associated with CF was only revealed by culture-independent techniques. The sequence comparison enabled confident determination of the bacterial community composition and revealed a high diversity and individuality in the communities across the cohort. Results of microbiological analyses were further compared with individual host factors, such as age, lung function and CFTR genotype. No statistical relationship between these factors and the diversity of the entire community or single bacterial species could be identified. However, patients with non-ΔF508 mutations in the CFTR gene often had low abundances of Pseudomonas aeruginosa. Persistence of specific bacteria in some communities was demonstrated by longitudinal analyses of 13 patients indicating a potential clinical relevance of anaerobic bacteria, such as Fusobacterium nucleatum and Streptococcus millerii.

Conclusions

The high individuality in community composition and the lack of correlation to clinical host factors might be due to the continuous treatment with antibiotics. Since this is current practice for adult CF patients, the life-long history of the patient and the varying selection pressure on the related microbial communities should be a focus of future studies and its relation to disease progression. These studies should be substantially larger, providing more molecular information on the microbial communities complemented by detailed genetic assessment of the host.