Cystic fibrosis: An update for clinicians. Part 1: Nutrition and gastrointestinal complications

A Gastroenterologist's Guide to Care Transitions in Cystic Fibrosis from Pediatrics to Adult Care

Cystic Fibrosis is a chronic disease affecting multiple systems, including the GI tract. Clinical manifestation in patients can start as early as infancy and vary across different age groups. With the advent of new, highly effective modulators, the life expectancy of PwCF has improved significantly. Various GI aspects of CF care, such as nutrition, are linked to an overall improvement in morbidity, lung function and the quality of life of PwCF. The variable clinical presentations and management of GI diseases in pediatrics and adults with CF should be recognized. Therefore, it is necessary to ensure efficient transfer of information between pediatric and adult providers for proper continuity of management and coordination of care at the time of transition. The transition of care is a challenging process for both patients and providers and currently there are no specific tools for GI providers to help ensure a smooth transition. In this review, we aim to highlight the crucial features of GI care at the time of transition and provide a checklist that can assist in ensuring an effective transition and ease the challenges associated with it.

Changing paradigms in the treatment of gastrointestinal complications of cystic fibrosis in the era of cystic fibrosis transmembrane conductance regulator modulators

Cystic fibrosis (CF) - although primarily a lung disease - also causes a variety of gastrointestinal manifestations which are important for diagnosis, prognosis and quality of life. All parts of the gastrointestinal tract can be affected by CF. Besides the well-known pancreatic insufficiency, gastroesophageal reflux disease, liver disease and diseases of the large intestine are important pathologies that impact on prognosis and also impair quality of life. Diagnosis and management of gastrointestinal manifestations will be discussed in this review. Since optimisation of CF therapy is associated with a significantly longer life-span of CF patients nowadays, also gastrointestinal malignancies, which are more common in CF than in the non-CF population need to be considered. Furthermore, novel evidence on the role of the gut microbiome in CF is emerging. The introduction of cystic fibrosis transmembrane conductance regulator (CFTR) protein modulators gives hope for symptom alleviation and even cure of gastrointestinal manifestations of CF.

Brazilian Guidelines for Nutrition in Cystic Fibrosis

OBJECTIVE

To develop a scientific consensus on nutrition in cystic fibrosis.

METHODS

Sixteen coordinators elaborated relevant questions on nutritional therapy in cystic fibrosis, which were divided into six sections: nutritional assessment, nutritional recommendations, nutritional intervention, dietary counseling, special situations and enzyme replacement, and gastrointestinal manifestations. Two to three specialists in the field were responsible for each section and obtaining answers formulated based on standardized bibliographic searches. The available literature was searched in the PubMed®/MEDLINE database, after training and standardization of search strategies, to write the best level of evidence for the questions elaborated. Issues related to disagreement were discussed until a consensus was reached among specialists, based on the current scientific literature.

RESULTS

Forty-two questions were prepared and objectively answered, resulting in a consensus of nutritional therapy in cystic fibrosis.

CONCLUSION

This work enabled establishing a scientific consensus for nutritional treatment of cystic fibrosis patients.

Vitamin D supplementation in patients with cystic fibrosis: A systematic review and meta-analysis

Despite routine supplementation, vitamin D insufficiency is often seen in cystic fibrosis (CF) patients on account of pancreatic insufficiency. Vitamin D is a crucial component of bone health and affects nearly all cells of the immune system. However, clinical benefits or harms associated with supplementation are poorly documented. In this systematic review, we included randomized controlled trials (RCTs) that compared vitamin D supplementation with placebo (i.e. 'non-increased dose') in CF patients. Analysing the 8 included RCTs, the intervention group had significantly higher serum 25-hydroxyvitamin D (se25OHD) levels, but there were no significant differences found in the quantitative synthesis of clinical outcomes, including bone disease-, respiratory status- and immunological status-related outcomes. Based on our current results, while a higher vitamin D dose elevates se25OHD, it does not seem to influence clinical outcomes. Future RCTs should include outcomes of past studies and apply longer follow-up periods to document long-term patient-important outcomes.

Prevalence of constipation in cystic fibrosis patients: a systematic review of observational studies

OBJECTIVE

To systematically revise the literature in search of data about the prevalence of constipation in patients with cystic fibrosis according to the publications in this field, which partly refer to guidelines defined in 2010 by the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition.

SOURCES

Systematic review selecting articles based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, including Cystic Fibrosis patients of all ages. Sources of information were selected to identify the articles without period limitation: CADTH - Canadian Agency for Drugs and Technologies in Health, CINAHL Complete, Clinical Trials US NIH, Cochrane Library, Embase, MEDLINE via Ovid, Scopus, Web Of Science, PubMed, SciELO, MEDLINE and LILACS , Health Systems Evidence, PDQ Evidence, CRD Canadian Agency for Drugs and Technologies in Health, INAHTA - International Network of Agencies for Health Technology Assessment, and PEDro.

FINDINGS

The prevalence of constipation was reported in eight observational studies. Only two studies assessed the frequency of constipation as a primary objective; in the others, constipation was quoted along with the prevalence of the spectrum of gastrointestinal manifestations. Altogether, the publications included 2,018 patients, the reported prevalence varied from 10% to 57%. Only two of the six articles published after 2010 followed the definition recommended by the European Society.

CONCLUSIONS

Constipation is a frequent but still insufficiently assessed complaint of Cystic Fibrosis patients. The use of diverse diagnostic criteria restricts comparison and epidemiological conclusions, future studies should compulsorily apply the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition definition.

Dietary Macronutrient Distribution and Nutrition Outcomes in Persons with Cystic Fibrosis: An Evidence Analysis Center Systematic Review

Cystic fibrosis (CF) increases risk for undernutrition and malabsorption. Individuals with CF traditionally have been counseled to consume a high-fat diet. However, a new era of CF care has increased lifespan and decreased symptoms in many individuals with CF, necessitating a re-examination of the high-fat CF legacy diet. A literature search was conducted of Medline (Ovid), Embase, and CINAHL (EBSCO) databases to identify articles published from January 2002 to May 2018 in the English language examining the relationships between dietary macronutrient distribution and nutrition outcomes in individuals with CF. Articles were screened, risk of bias was assessed, data were synthesized narratively, and each outcome was graded for certainty of evidence. The databases search retrieved 2,519 articles, and 7 cross-sectional articles were included in the final narrative analysis. Three studies examined pediatric participants and 4 examined adults. None of the included studies reported on outcomes of mortality or quality of life. Very low certainty evidence described no apparent relationship between dietary macronutrient distribution and lung function, anthropometric measures, or lipid profile in individuals with CF. The current systematic review demonstrates wide ranges in the dietary macronutrient intakes of individuals with CF with little to no demonstrable relationship between macronutrient distribution and nutrition-related outcomes. No evidence is presented to substantiate an outcomes-related benefit to a higher fat-diet except in the context of achieving higher energy intakes in a lesser volume of food.

Re-imagining cystic fibrosis care: next generation thinking

Cystic fibrosis (CF) is a common multi-system genetically inherited condition, predominately found in individuals of Caucasian decent. Since the identification of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene in 1989, and the subsequent improvement in understanding of CF pathophysiology, significant increases in life-expectancy have followed. Initially this was related to improvements in the management and systems of care for treating the various affected organ systems. These cornerstone treatments are still essential for CF patients born today. However, over the last decade, the major advance has been in therapies that target the resultant genetic defect: the dysfunctional CFTR protein. Small molecule agents that target this dysfunctional protein via a variety of mechanisms have led to lung function improvements, reductions in pulmonary exacerbation rates and increases in weight and quality-of-life indices. As more patients receive these agents earlier and earlier in life, it is likely that general CF care will increasingly pivot around these specific therapies, although it is also likely that effects other than those identified in the initial trials will be discovered and need to be managed. Despite great excitement for modulator therapies, they are unlikely to be suitable or available for all; whether this is due to a lack of availability for specific CFTR mutations, drug-reactions or the health economic set-up in certain countries. Nevertheless, the CF community must be applauded for its ongoing focus on research and development for this life-limiting disease. With time, personalised individualised therapy would ideally be the mainstay of CF care.

Bile acid homeostasis in gastrointestinal and metabolic complications of cystic fibrosis

With the improved treatment of the pulmonary complications of cystic fibrosis (CF), gastrointestinal problems have become more important in the morbidity in CF. A hallmark of the gastrointestinal phenotype of CF, apart from pancreatic insufficiency, is a disruption of bile acid homeostasis. Bile acid homeostasis is important for many gastrointestinal processes including fat absorption, inflammation, microbial composition, as well as regulation of whole body energy metabolism. This review describes the impairment of bile acid homeostasis in CF, its possible consequences for gastrointestinal and metabolic complications and its potential as a target for therapy.

Practical approach to the gastrointestinal manifestations of cystic fibrosis

Cystic fibrosis (CF) is the most common, life-shortening, genetic illness affecting children in Australia and New Zealand. The genetic abnormality results in abnormal anion transport across the apical membrane of epithelial cells in a number of organs, including the lungs, gastrointestinal tract, liver and genito-urinary tract. Thus, CF is a multi-system disorder that requires a multi-disciplinary approach. Respiratory disease is the predominant cause of both morbidity and mortality in patients with CF. However, there are significant and clinically relevant gastrointestinal, liver, pancreatic and nutritional manifestations that must be detected and managed in a timely and structured manner. The aim of this review is to provide evidence-based information and clinical algorithms to guide the nutritional and gastrointestinal management of patients with CF.

The treatment of the pulmonary and extrapulmonary manifestations of cystic fibrosis

Cystic fibrosis (CF) is a complex multisystem disease with considerable between patient variability in its manifestations and severity. In the past several decades, the range of treatments and the evidence to support their use for the pulmonary and extrapulmonary manifestations of CF have increased dramatically, contributing to the improved median survival of patients. As therapy for CF has evolved, new challenges including treatment adherence, medication intolerance and allergy, medical complications and coping with the burden of disease in the context of having a family and managing employment have arisen. While the majority of current therapy focuses primarily on improving symptoms, new therapies (CFTR modulators) target the underlying genetic defect.

The Enigmatic Gut in Cystic Fibrosis: Linking Inflammation, Dysbiosis, and the Increased Risk of Malignancy

PURPOSE OF REVIEW

Intestinal inflammation, dysbiosis, and increased gastrointestinal malignancy risks are well-described in patients with cystic fibrosis (CF). However, there is limited understanding of their pathophysiology. This review aims to discuss these issues and assess potential links between them.

RECENT FINDINGS

Evidence of links between intestinal inflammation and dysbiosis (an imbalance in intestinal microbial populations) exist. Recent studies have demonstrated reduction in intestinal inflammation with probiotic administration. Both bacterial dysbiosis and gut inflammation contribute to the suboptimal nutritional status seen in children with CF. Short-chain fatty acids may be reduced in the gut lumen as a result of bacterial imbalances and may promote inflammation. Inflammation and bacterial dysbiosis in CF may also contribute to emerging adult complications such as gastrointestinal malignancy. An increase in carcinogenic microbes and reduction in microbes protective against cancer have been found in CF, linking bacterial dysbiosis and cancer. Murine studies suggest the CF gene, cystic fibrosis transmembrane conductance regulator (CFTR) gene, itself may be a tumour suppressor gene. The pathophysiology of interactions among intestinal inflammation, dysbiosis, and malignancy in CF is not clearly understood and requires further research.

Growth assessment and risk factors of malnutrition in children with cystic fibrosis

Objectives:

To evaluate the nutritional status, to screen for the presence of malnutrition, and to study the possible risk factors associated with malnutrition in patients with cystic fibrosis (CF).

Methods:

A retrospective cross-sectional review of medical records of all diagnosed CF patients in the Pediatric Department, Salmaniya Medical Complex, Manama, Kingdom of Bahrain, between January 1984 and May 2015 was conducted. Demographic and anthropometric data were collected from records of last visit to CF clinic. Nutritional status and risk factors of malnutrition were assessed.

Results:

All records of 109 CF patients were reviewed. Forty-seven pediatric patients were included in the study. All included patients were on pancreatic enzyme replacement and 42 (89%) received high-calorie supplementation. Growth failure was noted in 34 (72%) patients, 19 (56%) were wasted and stunted, 8 (23.5%) were wasted only, and 7 (20.5%) were stunted. Low birth weight (p=0.032), and the presence of gastroesophageal reflux disease (GERD) (p=0.039) were the significant risk factors for malnutrition.

Conclusion:

Most CF patients in Bahrain (72%) are malnourished. Low birth weight and the presence of GERD are risk factors.

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.

Gastrointestinal, Pancreatic, and Hepatobiliary Manifestations of Cystic Fibrosis

Pulmonary disease is the primary cause of morbidity and mortality in people with cystic fibrosis (CF), but significant involvement within gastrointestinal, pancreatic, and hepatobiliary systems occurs as well. As in the airways, defects in CFTR alter epithelial surface fluid, mucus viscosity, and pH, increasing risk of stasis through the various hollow epithelial-lined structures of the gastrointestinal tract. This exerts secondary influences that are responsible for most gastrointestinal, pancreatic, and hepatobiliary manifestations of CF. Understanding these gastrointestinal morbidities of CF is essential in understanding and treating CF as a multisystem disease process and improving overall patient care.

Gastric emptying and gastro-oesophageal reflux in children with cystic fibrosis

BACKGROUND

Gastro-oesophageal reflux (GOR) is common in patients with cystic fibrosis (CF). The aim of this study was to investigate the relationship between gastric emptying (GE) and GOR in children with CF.

METHODS

Multichannel intraluminal impedance-pH monitoring (MII-pH) to measure GOR and GE breath test (GEBT) to measure GE were performed in 28 children with symptoms suggestive for GOR disease (GORD) (group 1). GEBT was performed in another 28 children with/without GOR symptoms who agreed to undergo GEBT but not MII-pH (group 2).

RESULTS

In group 1, we found increased acid GOR (AGOR) in 46.4% and delayed GE (DGE) in 21.4% but no relationship between increased AGOR and DGE. There was no DGE in group 2. We found DGE in 10.7% and rapid GE in 12.5% of the whole group.

CONCLUSIONS

Almost half of the children with CF and symptoms suggestive for GORD have increased AGOR and almost a quarter has DGE. However, there was no relation between GOR and GE.