Challenges in the dietary treatment of cystic fibrosis related diabetes mellitus

Exercise and Cystic Fibrosis

Cystic fibrosis (CF) is an autosomal recessive, inherited congenital disease caused by the mutation of the family autosomal CF gene, with cumulative exocrine secretion characterized by inflammation, tracheal remodeling, and mucus accumulation. With the development of modern medical technology, CF patients are living longer lives and receiving more and more treatments, including traditional drugs, physical therapy, and gene therapy. Exercise is widely used to prevent and treat metabolic diseases such as cardiovascular diseases, obesity, diabetes, and metabolic syndrome. Regular exercise is beneficial to aerobic capacity and lung health. Exercise therapy has been of great interest since people realized that CF can be affected by exercise. Exercise alone can be used as an ACT (airway clearance technique), which promotes the removal of mucosal cilia. Exercise therapy is more easily accepted by any society, which helps to normalize the lives of CF patients, rather than placing a psychological burden on them. In this chapter, we will review the latest research progress about exercise in CF.

Dietary interventions for managing glucose abnormalities in cystic fibrosis: a systematic review protocol

BACKGROUND

Glucose abnormalities in cystic fibrosis (CF) are common, but there is limited evidence to guide their dietary management. Progressive impaired glucose tolerance eventually leads to cystic fibrosis-related diabetes (CFRD), the most prevalent complication of CF, which is associated with increased morbidity and mortality. Optimising glycaemic control improves clinical status and reduces mortality; insulin therapy is the primary means of controlling glycaemia in CFRD, but its role in managing pre-diabetes is less clear. CF dietary therapy requires a high calorie diet due to increased energy expenditure and malabsorption, but this energy-dense diet is typically high in fat and sugar, and high sugar intakes often result in hyperglycaemia in individuals who have impaired glucose handling. Current guidelines for the dietary management of glucose abnormalities in CF are based on clinical consensus rather than empirical evidence. A systematic review conducted in 2012 on the effects of low glycaemic index dietary intervention in CF concluded that there is a dearth of evidence in this area. This review will update the systematic review by Balzer et al. in 2012 and will broaden the scope of their review to include any type of dietary intervention for managing glucose abnormalities in CF.

METHODS

Quantitative studies of dietary interventions to manage glucose abnormalities in individuals aged over 5 years with CF and glucose abnormalities will be reviewed. No limits will be placed on language or study design. The comparator will be standard CF dietary therapy (energy dense, high-fat diet) in addition to insulin therapy for individuals with CFRD. Electronic databases will be searched for completed quantitative studies published in peer-review journals that focus on dietary interventions for managing glucose abnormalities in CF. Searches will be conducted from 2000 up to the present day to reflect the evolving improvements in CF management. No restrictions will be placed on study design or language. Duration of the dietary intervention must be a minimum of 2 months and only interventions in out-patient or community settings will be included. Studies must report on dietary intervention, glycaemic control, anthropometry and lung function. Evidence will be assessed for heterogeneity and a narrative review or meta-analysis conducted as appropriate.

DISCUSSION

This systematic review will elucidate current knowledge of the effects of dietary interventions for managing glucose abnormalities in the vulnerable CF clinical population.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number: CRD42018085569 www.crd.york.ac.uk/prospero/.

Pharmacotherapy of diabetes in cystic fibrosis patients

IMPORTANCE OF THE FIELD

Cystic fibrosis-related diabetes (CFRD) is a unique type of diabetes. In this article I review the pathophysiology of CFRD to gain insight as to why these patients have clinical features of both type 1 and 2 diabetes (DM). The reader will also learn that, although CFRD is different from type 1 and 2 DM, the development of diabetes-induced complications is similar to other types of DM. These complications can include retinopathy, nephropathy and neuropathy resulting from uncontrolled hyperglycemia; however, hyperglycemia and/or insulin deficiency in people with CFRD may exacerbate underlying CF problems, such as decreased pulmonary function and weight loss.

AREAS COVERED IN THIS REVIEW

Review medical therapy of CFRD including the over-riding goal of maintaining blood glucose levels in a range as close to normal as possible. The other important goal for diabetes management is to prevent diabetes complications and to encourage psychological wellbeing of the patient. However, as reviewed in this article, the underlying medical condition of people with CF and the basic metabolic differences caused by the disease often provide challenges in maintaining optimal diabetes control.

WHAT THE READER WILL GAIN

The reader will gain an understanding of how CFRD physically affects the patient with CF and the various pharmacologic therapies available for treatment of this type of diabetes. Furthermore they will gain insight into areas where more research is needed.

TAKE HOME MESSAGE

Cystic fibrosis-related diabetes is unique to CF and thus deserves disease specific medical therapy.

Symposium 6: Young people, artificial nutrition and transitional care The nutritional challenges of the young adult with cystic fibrosis: transition

Cystic fibrosis (CF) is a complex multisystem disorder affecting mainly the gastrointestinal tract and respiratory system. Intestinal malabsorption occurs in approximately 90% of patients. In the past, malnutrition was an inevitable consequence of disease progression, leading to poor growth, impaired respiratory muscle function, decreased exercise tolerance and immunological impairment. A positive association between body weight and height and survival has been widely reported. The energy requirements of patients with CF vary widely and generally increase with age and disease severity. For many young adults requirements will be 120–150% of the age-related estimated average requirement. To meet these energy needs patients are encouraged to eat a high-fat high-energy diet with appropriate pancreatic enzyme supplements. Many patients are unable to achieve an adequate intake as a result of a variety of factors including chronic poor appetite, infection-related anorexia, gastro-oesophageal reflux and abdominal pain. Oral energy supplements and enteral tube feeding are widely used. Nutritional support has been shown to improve nutritional status and stabilise or slow the rate of decline in lung function. With such emphasis on nutritional intake and nutritional status throughout life, poor adherence to therapies and issues relating to body image are emerging. The median survival of patients with CF is increasing. CF is now considered a life-limiting disease of adulthood rather than a terminal childhood illness. With increased longevity new challenges are emerging that include the transition of young adults with CF to adult services, CF-related diabetes, disordered eating, osteoporosis, liver disease and transplantation.

Isolation, motivation and balance: living with type 1 or cystic fibrosis-related diabetes

AIMS AND OBJECTIVES

To explore patients' responses to developing and managing cystic fibrosis-related diabetes and to contrast their views with those of individuals with type 1 diabetes mellitus.

BACKGROUND

The incidence of diabetes among people with cystic fibrosis has increased with improvement in life expectancy. However, little is known about how patients respond to and manage cystic fibrosis-related diabetes, and how this compares with people living with type 1 diabetes mellitus.

DESIGN

Qualitative research was undertaken in order to fully explore meanings and views.

METHODS

Semi-structured telephone or face-to-face interviews were conducted with patients who had cystic fibrosis-related diabetes or type 1 diabetes mellitus, during which, they discussed diagnosis and management of diabetes. Framework analysis was employed to identify themes and to consider similarities and differences between the two groups.

RESULTS

Eleven cystic fibrosis-related diabetes and 12 type 1 diabetes mellitus patients were interviewed in 2006. Patients with cystic fibrosis-related diabetes described their diabetes diagnosis as a progression of their primary illness, management of which was important owing to the benefits it brought to their cystic fibrosis. Those with type 1 diabetes mellitus were more likely to report feeling psychologically low because of diabetes and to list long-term complications as a key factor motivating self-management. Both groups struggled to balance the demands of diabetes with other life and health obligations, and experienced isolation because of diabetes. Conclusions. Variation in perceptions recalled during interviews stemmed from diabetes being part of an existing life-threatening chronic illness in people with cystic fibrosis-related diabetes. Similarities and differences in attitudes and management practices were found, with less urgency regarding glucose monitoring and fewer information resources available for those with cystic fibrosis-related diabetes.

RELEVANCE TO CLINICAL PRACTICE

Both groups need support for optimal diabetes management and access to appropriate resources outside specialist clinics. Web-based technologies could prove useful for those with cystic fibrosis-related diabetes as face-to-face interaction may be prevented owing to the risk of cross-infection.

Le diabète de la mucoviscidose chez l’adulte

Cystic fibrosis is an autosomal recessive disorder affecting about 1/3500 case in France. The disease, that affects all epithelia, is responsible for pulmonary tract infections but also pancreas, gut, liver and genital tract abnormalities. It is linked to CFTR gene mutations, inducing unusually high increase of sodium chloride in sweat, used to track down the illness. deltaF508 CFTR mutation, encountered in 70% of cases, is nearly always associated to pancreatic insufficiency with early-onset lung attack. Around 10% of cystic fibrosis cases, whatever the age, are complicated with partially insulinopenic diabetes, favored by pancreatic fibrosis, while one third of patients shows glucose intolerance. After 20 years old, one third of patients suffers from diabetes and one half after 30 years. Diabetes diagnosis is difficult, and requires the fulfillment of oral glucose tolerance test (OGTT). One glycemia greater or equal to 2 g/l, two hours after a 75 g glucose load, established diabetes diagnosis. Indeed, fasting blood glucose and glycated hemoglobin appear as poor diagnosis markers. Despite histological arguments in favor of the mainly mechanical islet disturbances, an increased prevalence of anti-islets auto-antibodies and an increased frequency of HLA DR3/DR4 have been reported in cystic fibrosis population with glucose tolerance troubles. Also, glucose metabolism is influenced by specific factors linked to cystic fibrosis (infection, malnutrition, steroids...). In reason of the silent phase of diabetes, systematic tracking down of diabetes with a yearly OGTT is recommended, all the more so that hyperglycemia appears as a worsening factor of cystic fibrosis. The efficacy of oral anti-diabetic drugs has not been evaluated on large studies. By contrast, some studies argue for insulin therapy as soon as diabetes appears, insulin improving respiratory and nutritional prognosis. In conclusion, the aim of treatment of cystic fibrosis is to prevent the lung function decline by controlling inflammation and infection, to implement endo- and exo-crine pancreas insufficiency, and to improve nutritional status.

Decreased lung function in female but not male subjects with established cystic fibrosis-related diabetes

OBJECTIVE

Although cystic fibrosis-related diabetes (CFRD) is associated with decreased lung function, sex is not known to influence CFRD. However, compared with male subjects with cystic fibrosis, female subjects with cystic fibrosis have increased morbidity. This study examines the association between female subjects with CFRD and poor lung function relative to male subjects using the percent predicted forced expiratory volume in 1 s (FEV(1)) as a surrogate measure of morbidity.

RESEARCH DESIGN AND METHODS

We compared 323 patients with established CFRD with 489 cystic fibrosis control subjects with normal glucose tolerance (NGT) listed in the U.K. Cystic Fibrosis Database. Patients stratified by sex and chronic Pseudomonas aeruginosa infection were compared using binary logistic regression, and patients with new CFRD diagnoses were compared prospectively for the year 2002.

RESULTS

CFRD in female subjects (but not male subjects) without chronic P. aeruginosa infection had a 20% lower percent predicted FEV(1) compared with control subjects with NGT (95% CI -11.7 to -27.7; P < 0.0001). Genotype, age, treatment center, age at diagnosis of cystic fibrosis, pregnancy, liver function, or dose of pancreatic enzyme replacement therapy did not confound this female disadvantage. Comparison of female subjects with newly diagnosed CFRD free of chronic P. aeruginosa infection with matched control subjects with NGT showed no FEV(1) disadvantage in the 1st year after CFRD diagnosis.

CONCLUSIONS

Only female subjects with CFRD have significantly decreased lung function compared with sex-matched NGT control subjects. The absence of poor lung function in the first 12 months after diagnosis of diabetes suggests that an opportunity may exist to intervene and possibly prevent a decline in lung function, which can be as much as 20% in female subjects with CFRD.

Changes in response to insulin and the effects of varying glucose tolerance on whole-body protein metabolism in patients with cystic fibrosis

BACKGROUND

Diabetes mellitus has been reported to increase whole-body protein breakdown and thus loss of lean body mass. Cystic fibrosis-related diabetes (CFRD) is associated with undernutrition and increased mortality.

OBJECTIVE

We hypothesized that CFRD is associated with increased whole-body protein breakdown, which results in negative protein balance, and that correction of the glucose intolerance with insulin therapy would normalize whole-body protein metabolism.

DESIGN

Rates of whole-body protein turnover and protein balance were measured in 28 adults with cystic fibrosis (17 M, 11 F). Subjects were assessed with a modified oral-glucose-tolerance test and categorized as having normal glucose tolerance, impaired glucose tolerance, or CFRD with and without fasting hyperglycemia; then they were compared with previously diagnosed CFRD adults already receiving insulin therapy. Indexes of protein turnover were calculated from [15N]glycine and 15N in urinary urea.

RESULTS

Analysis of variance for the 28 subjects showed that whole-body protein breakdown was highest (P<0.05) in patients with CFRD. Whole-body protein synthesis was not significantly affected by impaired glucose tolerance. Significant (P<0.05) improvement in net protein synthesis occurred in the CFRD group 3 mo after insulin therapy was administered. Follow-up studies of 3 subjects with CFRD showed significant improvement in net protein synthesis after insulin therapy. Monitoring of the protein homeostasis of the impaired glucose tolerance group gave clues to the progression of their metabolic homeostasis.

CONCLUSION

CFRD has an adverse effect on protein homeostasis by increasing net protein synthesis.

Family functioning in young children with cystic fibrosis: observations of interactions at mealtime

This study examined family functioning at mealtime, a context relevant to the management of cystic fibrosis (CF). Thirty-three families of children with CF and a control sample of 33 families of children without a chronic illness were assessed. Family functioning was rated during a videotaped dinner using the McMaster Mealtime Interaction Coding System (MICS), and mealtime behavioral problems were assessed using the Behavioral Pediatrics Feeding Assessment Scale (BPFAS). Ratings for families of children with CF were lower than for control families on overall functioning and five of six MICS dimensions (Communication, Interpersonal Involvement, Behavior Control, Affect Management, Roles). In families of children with CF, better family functioning was related to less frequently occurring mealtime behavioral problems (BPFAS); however, family functioning was not related to the child's weight status or the child's caloric intake. Data support that nutritional intervention may be maximized if dietary adherence is promoted in the context of positive parent-child and family interactions.

The implementation of nutritional advice for people with diabetes

These consensus-based recommendations emphasize the practical implementation of nutritional advice for people with diabetes, and describe the provision of services required to provide the information. Important changes from previous recommendations include greater flexibility in the proportions of energy derived from carbohydrate and monounsaturated fat, further liberalization in the consumption of sucrose, more active promotion of foods with a low glycaemic index, and greater emphasis on the provision of nutritional advice in the context of wider lifestyle changes, particularly physical activity. Monounsaturated fats are now promoted as the main source of dietary fat because of their lower susceptibility to lipid peroxidation and consequent lower atherogenic potential. Consumption of sucrose for patients who are not overweight can be increased up to 10% of daily energy provided that this is eaten in the context of a healthy diet and distributed throughout the day [corrected]. Evidence is presented for the effectiveness of advice provided by trained dieticians. The increasing evidence for the importance of good metabolic control and the growing requirement for measures to prevent Type 2 diabetes in an increasingly obese population will require major expansion of dietetic services if the standards in National Service Frameworks are to be successfully implemented.

Cystic fibrosis-related diabetes

Diabetes mellitus (DM) has been recognized as a complication of cystic fibrosis (CF) for almost 50 years and commonly develops around 20 years of age. The prevalence increases with age and, with improved survival of those with CF, approaches 30% in certain centres. Its development appears to have a significant impact on pulmonary function and may increase mortality by up to six-fold. Subjects with CF are rarely ketosis-prone and phenotypically lie between Type 1 and Type 2 DM. Microvascular complications are recognized, although paucity of data does not permit a clear description of their natural history. An annual oral glucose tolerance test from the age of 10 years is recommended for screening, but logistical difficulties have led some groups to develop specific algorithms to aid diagnosis. Insulin sensitivity in CF is much debated and may depend upon the degree of glucose intolerance. Insulin resistance occurs in the presence of infection, corticosteroid usage and hyperglycaemia, whilst hepatic insulin resistance is considered an adaptation to CF. There is no universal consensus on the treatment of hyperglycaemia. With increased longevity of individuals with CF, greater numbers will develop diabetes and the diabetes physician is destined to play a greater role in the multidisciplinary CF team.

Transition of care between paediatric and adult gastroenterology. Cystic fibrosis

Advancement in treatment has resulted in a dramatic increase in life expectancy of patients with cystic fibrosis (CF) to well beyond 30 years of age in most centres. What was once a fatal genetic disease in childhood now sees over a third of its CF populations in adult clinics. The improved survival is multifactorial, but most attribute the reasons to more aggressive nutritional care along with better management of the gastrointestinal and pulmonary systems. Many of the nutritional and GI issues of paediatric patients remain similar when they become adults, except that there is the added psychosocial stress associated with this transition. This chapter aims to highlight the gastrointestinal and nutritional issues manifesting at the different stages of life from infancy to adulthood, and the recommended management.

Management of cystic fibrosis-related diabetes in adolescence

Cystic fibrosis (CF) and type 1 diabetes are two of the most common chronic childhood conditions in the UK; the management of each comprises demanding and perpetual daily regiments. As the life expectancy of patients with CF has improved, there has been a corresponding increase in the number of patients developing CF-related diabetes (CFRD), some of whom are teenagers. For a number of reasons, non-adherence to treatment is a recognized problem in chronically ill teenagers, a problem exacerbated when CF and diabetes co-exist. There is a scarcity of literature concerning CFRD management, particularly in relation to adolescence, with recommendations often being based on anecdotal evidence. In this article, the aetiology, incidence, diagnosis and management of CFRD are outlined. Chronic illness in adolescence and the problem of non-compliance are explored and considered in the context of CFRD. Recommendations for practice for health professionals caring for teenagers with CFRD are offered.

Glucose intolerance in children with cystic fibrosis

OBJECTIVE

To evaluate the relations among glucose intolerance, genotype, and exocrine pancreatic status in patients with cystic fibrosis (CF).

STUDY DESIGN

Data on 335 patients <18 years of age were from the Toronto CF database. A modified oral glucose tolerance test was given to 94 patients 10 to 18 years of age without recognized CF-related diabetes. CF transmembrane conductance regulator mutations and exocrine pancreatic status were determined for all patients.

RESULTS

CF-related diabetes was clinically recognized in 9 of 335 (2.7%) patients <18 years of age, all of whom were pancreatic insufficient, and 8 of 9 had severe (classes I through III) mutations on both alleles. The ninth patient had unidentified mutations. Although all patients given the oral glucose tolerance test were asymptomatic and had normal fasting blood glucose, 16 of 94 (17%) had impaired glucose tolerance and 4 of 94 (4.3%) had CF-related diabetes without fasting hyperglycemia. Abnormal glucose tolerance was associated exclusively with severe mutations and exocrine pancreatic insufficiency. Glycosylated hemoglobin (HbA(1)C) levels did not correlate with glucose tolerance results.

CONCLUSIONS

Screening of pancreatic-insufficient, adolescent patients with CF identified more with abnormal oral glucose tolerance than was suspected clinically and is recommended as a routine practice. HbA(1)C was not useful in screening for CF-related glucose intolerance.