A Practical Approach to Glucose Abnormalities in Cystic Fibrosis

Glycemic variability in chronic calcific pancreatitis with diabetes mellitus and its possible determinants

AIMS

To study glycemic patterns and variability in patients with pancreatic diabetes or type 3c Diabetes mellitus (DM) due to chronic pancreatitis and its subtypes and assess the role of pancreatic enzyme replacement therapy (ERT) in modulating glycemic variability.

METHODS

Patients having type 3c DM due to chronic pancreatitis, and on insulin underwent Flash continuous-glucose-monitoring (CGM) for 14 days. Parameters were compared between patients with fibrocalculous pancreatic diabetes (FCPD) and non-FCPD-chronic calcific pancreatitis (non-FCPD) and between the recipients and non-recipients of pancreatic enzyme-replacement-therapy (ERT).

RESULTS

Out of 54 patients with pancreatic diabetes, 35 patients had chronic calcific pancreatitis. They underwent CGM, median HbA1c 9.20 % (77 mmol/mol) and mean Time-In-Range (TIR) being 41.21 % (23.48). Only 5 (15.2 %) patients achieved target TIR>70 % while 16 (48.5 %) patients had high glycemic-variability [Coefficient-of-variation (CV) > 36 %]. Patients with FCPD (n = 14) had higher hypoglycemia-indices like Time-Below-Range (18.92 % vs 8.20 %; p = 0.03) and Low-Blood-Glucose-Index (18.14 % vs 6.04 %; p = 0.02) compared to non-FCPD (n = 21). HbA1c% and hyperglycemic excursions were similar in both groups. Recipients of ERT (n = 20) had lower glycemic-variability [Standard Deviation (SD) 52.15 % vs 68.14 % and CV 32.59 % vs 41.79 %, p < 0.05 for both) than non-recipients. ERT-recipients had no serious hypoglycemia within the 14 days. On subgroup analysis, lower glycemic-variability and hypoglycemia with ERT were seen only in FCPD but not in non-FCPD subgroup (50.13 vs 77.91, 30.09 vs 48.36 for SD and CV respectively, p < 0.05).

CONCLUSION

Patients with type 3c DM due to chronic pancreatitis have high frequency of hyperglycemic and hypoglycemic excursions, with those with FCPD having a particularly higher risk of hypoglycemia and glycemic-variability. Those receiving pancreatic ERT had lesser glycemic variability and hypoglycemia. The small sample size and lack of objective markers of documentation of exocrine pancreatic insufficiency like fecal elastase highlight the need for further larger studies in this field.

Clinical Observations in Patients With Cystic Fibrosis-Related Diabetes and Self-Reported Ototoxicity Symptoms

PURPOSE

Persons with cystic fibrosis (PwCF) are at high risk for ototoxicity due to the routine use of intravenous aminoglycoside (IV-AG) antibiotics in respiratory infection management. Additionally, factors that contribute to ototoxicity-related symptom development and severity in PwCF are unknown. Given the increased risk of ototoxicity in people with diabetes, we explored the association between cystic fibrosis-related diabetes (CFRD) and self-reported ototoxicity symptoms (tinnitus and vestibular problems) in PwCF treated with aminoglycosides.

METHOD

PwCF (N = 39; 25 females, 14 males; Mage = 30.1 years, SD = 10.3) were recruited from the Cystic Fibrosis Care Center at Oregon Health & Science University. Patients completed the validated questionnaires to ascertain their experiences with ototoxicity-related symptoms of tinnitus and balance function. The diagnosis of CFRD, including oral glucose tolerance testing (OGTT), insulin treatment, hemoglobin A1c, and cumulative IV-AG treatment history, was obtained through a medical chart review. Participants were classified into three groups based on their medical diagnoses via OGTT: normal glucose tolerance (NGT; control; n = 16), abnormal glucose tolerance (AGT; n = 9), and CFRD (n = 14). Participants in each group were further classified based on survey outcomes for ototoxicity-related symptoms.

RESULTS

There was a trend toward a higher proportion of patients with CFRD reporting tinnitus compared to the AGT and NGT groups, but did not meet statistical significance (X2 = 2.24, p = .13). Approximately, 43% of patients with CFRD reported experiencing clinically significant tinnitus lasting > 3 min compared to 11% in the AGT group and 13% in the NGT group (X2 = 3.751, p = .05). Cumulative IV-AG exposure tended to be higher in CFRD compared to other groups. High balance function was generally reported in all groups.

CONCLUSIONS

Patients with CFRD have greater ototoxicity-related symptoms. Further investigation of the relationship between CF-related comorbidities and the risk of developing ototoxicity-related symptoms is warranted to improve the detection and management of ototoxicity in PwCF.

Oxidative Stress Biomarkers in Cystic Fibrosis and Cystic Fibrosis-Related Diabetes in Children: A Literature Review

The most common inherited condition that results in death, particularly in those of Caucasian heritage, is cystic fibrosis (CF). Of all the young adults diagnosed with cystic fibrosis, 20% will develop hyperglycemia as a complication, later classified as a disease associated with cystic fibrosis. Impaired insulin secretion and glucose intolerance represent the primary mechanisms associated with diabetes (type 1 or type 2) and cystic fibrosis. Oxidative stress represents the imbalance between oxygen-reactive species and antioxidant defense mechanisms. This pathogenic mechanism is vital in triggering other chronic diseases, including cystic fibrosis-related diabetes. It is essential to understand oxidative stress and the significant impact it has on CFRD. This way, therapies can be individually adjusted and tailored to each patient's needs. This review aims to understand the connection between CFRD and oxidative stress. As a subsidiary element, we analyzed the effects of glycemic balance on complications and their evolution over time, providing insights into their potential benefits in mitigating oxidative stress-associated complications.

Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health

The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.

Development of liquid culture media mimicking the conditions of sinuses and lungs in cystic fibrosis and health

The respiratory tract is a compartmentalised and heterogenous environment. The nasopharynx and sinuses of the upper airways have distinct properties from the lungs and these differences may shape bacterial adaptation and evolution. Upper airway niches act as early colonisation sites for respiratory bacterial pathogens, including those, such as Pseudomonas aeruginosa, that can go on to establish chronic infection of the lungs in people with cystic fibrosis (CF). Despite the importance of upper airway environments in facilitating early adaptation to host environments, currently available in vitro models for study of respiratory infection in CF focus exclusively on the lungs. Furthermore, animal models, widely used to bridge the gap between in vitro systems and the clinical scenario, do not allow the upper and lower airways to be studied in isolation. We have developed a suite of culture media reproducing key features of the upper and lower airways, for the study of bacterial adaptation and evolution in different respiratory environments. For both upper and lower airway-mimicking media, we have developed formulations that reflect airway conditions in health and those that reflect the altered environment of the CF respiratory tract. Here, we describe the development and validation of these media and their use for study of genetic and phenotypic adaptations in P. aeruginosa during growth under upper or lower airway conditions in health and in CF.

Continuous glucose monitoring systems for monitoring cystic fibrosis-related diabetes

BACKGROUND

Cystic fibrosis (CF) is one of the most common life-shortening autosomal-recessive genetic conditions with around 100,000 people affected globally. CF mainly affects the respiratory system, but cystic fibrosis-related diabetes (CFRD) is a common extrapulmonary co-morbidity and causes excess morbidity and mortality in this population. Continuous glucose monitoring systems (CGMS) are a relatively new technology and, as yet, the impact of these on the monitoring and subsequent management of CFRD remains undetermined.

OBJECTIVES

To establish the impact of insulin therapy guided by continuous glucose monitoring compared to insulin therapy guided by other forms of glucose data collection on the lives of people with CFRD.

SEARCH METHODS

We searched the Cochrane Cystic Fibrosis Trials Register, compiled from electronic database searches and handsearching of journals and conference abstract books. Date of latest search: 23 September 2021. We also searched the reference lists of relevant articles and reviews and online trials registries. Date of last search: 23 September 2021.

SELECTION CRITERIA

Randomised controlled studies comparing insulin regimens led by data from CGMS (including real-time or retrospective data, or both) with insulin regimens guided by abnormal blood glucose measurements collected through other means of glycaemic data collection in people with CFRD. Studies with a cross-over design, even with a washout period between intervention arms, are not eligible for inclusion due to the potential long-term impact of each of the interventions and the potential to compromise the outcomes of the second intervention.

DATA COLLECTION AND ANALYSIS

No studies were included in the review, meaning that no data were available to be collected for analysis.

MAIN RESULTS

Review authors screened 14 studies at the full-text stage against the review's inclusion criteria. Consequently, seven were excluded due to the study type being ineligible (not randomised), two studies were excluded due to their cross-over design, and two studies was excluded since the intervention used was not eligible and one was a literature review. One study in participants hospitalised for a pulmonary exacerbation is ongoing. Investigators are comparing insulin dosing via insulin pump with blood sugar monitoring by a CGMS to conventional diabetes management with daily insulin injections (or on an insulin pump if already on an insulin pump in the outpatient setting) and capillary blood glucose monitoring. The participants in the control arm will wear a blinded continuous glucose monitoring system for outcome assessment. In addition to this, one further study is still awaiting classification, and will be screened to determine whether it is eligible for inclusion, or is to be excluded, in an update of this review.

AUTHORS' CONCLUSIONS

No studies were included in the review, indicating that there is currently insufficient evidence to determine the impact of insulin therapy guided by CGMS compared to insulin therapy guided by other forms of glucose data collection on the lives of people with CFRD, nor on potential adverse effects of continuous glucose monitoring in this context. Randomised controlled studies are needed to generate evidence on the efficacy and safety of continuous glucose monitoring in people with CFRD. There is one relevant ongoing study that may be eligible for inclusion in a future update of this Cochrane Review, and whose results may help answer the review question.

Cystic fibrosis related diabetes is not independently associated with increased Stenotrophomonas maltophilia infection: Longitudinal data from the UK CF Registry

INTRODUCTION

Stenotrophomonas maltophilia is common in the sputum of people with cystic fibrosis related diabetes (CFRD), raising the question as to whether this is a risk factor for its acquisition. We investigated this at a population level.

METHODS

We analysed national Cystic Fibrosis Registry data 2011-2015 for 8047 people with CF > age 6 years, looking at demographics, diagnosis of CFRD, lung function and sputum microbiology; using descriptive and multivariate strategies to establish independent predictors for S. maltophilia culture and associated outcomes.

RESULTS

S. maltophilia was present in 1148 (14.1%). Although univariate analysis confirmed it was more prevalent in those with CFRD, when adjusted for other clinical parameters there was no longer a relationship. Markers of more severe lung disease were independent risk-factors for S. maltophilia.

CONCLUSION

Although S. maltophilia is more common in people with CFRD, it is not an independent risk-factor for S. maltophilia acquisition.

Cystic Fibrosis Transmembrane Regulator Modulators: Implications for the Management of Depression and Anxiety in Cystic Fibrosis

BACKGROUND

Individuals with cystic fibrosis (CF) are at high risk for depression and anxiety, which are associated with worse medical outcomes. Novel therapies for CF hold great promise for improving physical health, but the effects of these therapies on mental health remain poorly understood.

OBJECTIVE

This review aims to familiarize psychiatrists with the potential effect of novel CF therapies on depression and anxiety.

METHODS

We discuss novel therapies that directly target the mutant CF protein, the CF transmembrane regulator (CFTR), which are called CFTR modulators. We summarize depression and anxiety screening and treatment guidelines under implementation in accredited CF centers. Case vignettes highlight the complexities of caring for individuals with CF with comorbid depression and anxiety, including patients experiencing worsening depression and anxiety proximate to initiation of CFTR modulator therapy, and management of drug-drug interactions.

CONCLUSIONS

Although CFTR modulator therapies provide hope for improving clinical outcomes, worsening depression and anxiety occurs in some patients when starting these novel agents. This phenomenon may be multifactorial, with hypothesized contributions from CFTR modulator-psychotropic medication interactions, direct effects of CFTR modulators on central nervous system function, the psychologic effect of starting a potentially life-altering drug, and typical triggers of depression and anxiety such as stress, pain, and inflammation. The medical and psychiatric complexity of many individuals with CF warrants more direct involvement of mental health specialists on the multidisciplinary CF team. Inclusion of mental health variables in patients with CF registries will facilitate further examination at an epidemiologic level.