Association of race and ethnicity with the development of cystic fibrosis-related diabetes.

BACKGROUND: CF-related diabetes (CFRD) is a common, life-expectancy limiting complication of CF. While Black race and Hispanic ethnicity in youth-onset type 1 and type 2 diabetes are well-recognized risk factors for worse diabetes complications, the potential for racial/ethnic disparities in CFRD has received limited attention. METHODS: We conducted a retrospective cohort study utilizing the CF Foundation Patient Registry from 2010 to 2019 to determine the prevalence and incidence of CFRD by race/ethnicity. Three age cohorts were identified at baseline in 2010 (11-20y, 21-30y, and 31-40y). Logistic regression and Cox regression stratified by age group were used to determine the prevalence and incidence, respectively, among Hispanic, non-Hispanic Blacks (NHB), and non-Hispanic whites (NHW) after adjustment for relevant confounders, including demographics, socioeconomic status, clinical factors, and chronic medication use. RESULTS: Among 14,660 registry participants, 510 were NHB and 890 Hispanic. NHB associated with higher odds of CFRD baseline prevalence in all age cohorts (11-20y: OR 2.53 (95 % CI: 1.88-3.41, P < 0.05), 21-30y: OR 1.80 (1.25-2.59, P < 0.05), and 31-40y: OR 1.93 (1.00-3.73, P < 0.05)) relative to NHW. In the 11-20y cohort, the hazard of new-onset CFRD was 40 % higher in NHB (HR 1.40 (1.09-1.8, P < 0.05)) and 19 % higher in Hispanics (HR 1.19 (1.01-1.41, P < 0.05)). CONCLUSION: NHB had a higher prevalence of CFRD across all age groups, with NHB and Hispanics showing higher incidence of CFRD in the youngest group. Multicenter studies performed in diverse CF populations are warranted to identify modifiable factors influencing earlier CFRD development in minoritized groups and their potential contribution to diabetes complication disparities.

Impact of triple transmembrane regulator therapy on glucose metabolism in cystic fibrosis related diabetes during clinical practice.

AIMS: To evaluate the impact of elexacaftor/tezacaftor/ivacaftor (ETI) therapy on Cystic Fibrosis Related Diabetes (CFRD) glycemic control and insulin treatment in patients with CFRD during clinical practice. METHODS: We carried out a retrospective observational study of 23 adult patients with CFRD who started treatment with ETI. They had, at least, one F508del mutation. Data were collected before ETI initiation and 3, 6, and 12 months after. RESULTS: Glycemic control measured by HbA1c significantly improved by 0.3 % (0.1-0.5) after 3 months of ETI therapy (p = 0.004) and kept this improvement during follow-up (p < 0.001). The proportion of patients needing multiple daily injections of insulin was reduced by 16 % (p = 0.023). Total daily insulin dose dropped by 0.12 (0.05-0.18) UI/kg/day (p < 0.001). Data derived from Flash Continuous Glucose Monitoring (CGM) for patients treated with insulin stayed unchanged after insulin reduction, except for a significant 8 % (0.3-15.6) increase in the Time In Tight Range (TITR) between 70 and 140 mg/dL (p = 0.043). CONCLUSION: ETI therapy impacted CFRD in clinical practice reducing insulin needs and improving glycemic control measured by HbA1c and CGM. The improvements can be observed from the first 3 months of treatment.

Glucagon-like-peptide-1 agonist therapy in adults with cystic fibrosis.

Glucagon-like-peptide-1 (GLP-1) agonists are commonly used to improve glycemic control and promote weight loss in individuals with type 2 diabetes mellitus (T2DM) and/or obesity. However, there is a paucity of evidence regarding GLP-1 agonist use in people with cystic fibrosis (pwCF). We present 11 people with CF (males: 3, females: 7; age range 24-47; BMI range 25.7-43.7) treated with GLP-1 agonists (semaglutide: 9,tirzepatide: 2) for variable duration (1-50 months). All experienced weight loss on GLP- 1 agonist therapy (median change in weight = -7.2 kg; change in BMI [kg/m2] = -0.9 to -8.1). Eight pwCF showed improvement in percent predicted forced expiratory volume in 1 second (ppFEV1) [change = -5 to + 18] and nine pwCF showed improvement in percent predicted forced vital capacity (ppFVC) [change= +1 to + 26]. Of the 7 pwCF with CFRD, all reduced their insulin quantity (mean, 31.5 % decrease in total daily insulin dose), and glucose time in range improved for most (mean, +11 % increase from baseline). Four pwCF stopped using GLP-1 agonists: 2 due to severe nausea/vomiting, 1 due to lack of perceived benefit, and 1 due to change in insurance coverage. This report is the largest published series to date of pwCF treated with GLP-1 agonist therapy. With the addition of GLP-1 agonists, all individuals experienced weight loss and a reduction in daily insulin dose, and most had improvement in pulmonary function. Future multi-center studies are needed to corroborate the efficacy and safety of these agents in the CF population.

Efficacy of advanced hybrid closed loop systems in cystic fibrosis related diabetes: a pilot study.

Background and aims: Cystic fibrosis related diabetes (CFRD) is correlated with worsening of nutritional status and greater deterioration of lung function. The role of new technologies for the treatment of CFRD is little explored. The aim of the study was to evaluate the efficacy of Advanced Hybrid Closed Loop (AHCL) systems on glycemic control in CF patients. Methods: A single-center retrospective study on CFRD patients using AHCL systems was performed. Glycated hemoglobin (HbA1c) values and Continuous Glucose Monitoring (CGM) metrics were collected at T0 (AHCL placement), T1 (1-month), T2 (6-months) and T3 (1-year) to evaluate glycemic control. Results: 10 patients were included in the study. Data showed a reduction of HbA1c value (7.31 ± 0.34 to 6.35 ± 1.00; p=0.03), glycemic variability (p=0.05) and insulin requirement (p=0.03). The study population reached American Diabetes Association (ADA) recommended glycemic targets at 1-year. An increase in the Time in Range (TIR) and a reduction in time in hyperglycemia were also observed, although not statistically significant. Conclusions: In patients with CFRD, the use of AHCL leads to an improvement in glycemic control in terms of HbA1c and glycemic variability. The increase in TIR and the reduction of time in hyperglycemia, although not statistically significant, are extremely encouraging from a clinical point of view. Further studies with a larger population and a longer follow-up are needed. The results of this study demonstrate the importance of proposing the use of AHCL even in CF patients, who could benefit from glycemic improvement also in terms of nutritional status and respiratory function.

Offlabel use of Medtronic MiniMed 780G in the management of cystic fibrosis related diabetes in people requiring insulin total daily doses below 8 units: encouraging data from our population.

Cystic fibrosis (CF)-related diabetes (CFRD), characterized by partial to complete impaired insulin secretion, is the most common extra-pulmonary complication of CF. Actually, insulin is the only approved therapy for its management. Advanced hybrid closed loop (AHCL) systems are the gold standard therapy for type 1 diabetes and have been proposed for other insulin-dependent forms of diabetes, including CFRD. With AHCL systems, people with CFRD can better manage several typical disease-related issues, such as minimal insulin requirements, its variability due to exacerbations or concomitant steroid therapies, nutritional behaviors, the co-existence of CF complications as intestinal malabsorption or liver disease. SmartGuard, the AHCL system for Medtronic Minimed 780G, requires a minimum of 8 units per day to operate. In this paper, we expose a case of two young women with CFRD with total daily insulin requirements < 8 UI, using off-label SmartGuard system over a 3 years of follow-up period, suggesting an evaluation of its use also in people with minimal insulin needs, considering its beneficial impact in glucose control and quality of life.

Extracorpeal Membrane Oxygenation in a Cystic Fibrosis Patient With Septic Shock Due to Methicillin-Resistant Staphylococcus aureus.

This report presents the case of an 18-year-old male with cystic fibrosis (CF) who developed septic shock due to methicillin-resistant Staphylococcus aureus (MRSA) bacteremia. He had a history of poor nutritional status and uncontrolled CF-related diabetes, both contributing to his rapidly declining condition. Despite aggressive treatment, including extracorporeal membrane oxygenation, his hospital course continued to deteriorate, including worsening respiratory failure and the need for lower extremity amputation secondary to ischemia. Ultimately, the decision to withdraw life support was made after it was determined the patient had unrecoverable respiratory failure. Our goal in presenting this case is to demonstrate the serious consequences of MRSA infection in patients with CF, who are often severely immunocompromised, and to emphasize the need for early detection and aggressive intervention among patients of this group.

Advances in diabetes technology to improve the lives of people with cystic fibrosis.

People with cystic fibrosis (CF) are at risk for dysglycaemia caused by progressive beta cell dysfunction and destruction due to pancreatic exocrine disease and fibrosis. CF-related diabetes (CFRD) is a unique form of diabetes that has distinctive features from both type 1 and type 2 diabetes. Recent advances in diabetes technology may be of particular benefit in this population given the complex, multi-system organ involvement and challenging health issues that people with CFRD often face. This review summarises how diabetes technologies, such as continuous glucose monitors (CGMs) and insulin delivery devices: (1) have improved our understanding of CFRD, including how hyperglycaemia affects clinical outcomes in people with CF; (2) may be helpful in the screening and diagnosis of CFRD; and (3) offer promise for improving the management of CFRD and easing the burden that this diagnosis can add to an already medically complicated patient population.

Chronic hyperglycemia aggravates lung function in a Scnn1b-Tg murine model.

Cystic fibrosis-related diabetes (CFRD), the most common comorbidity in cystic fibrosis (CF), leads to increased mortality by accelerating the decline in lung function. Scnn1b-Tg transgenic mice overexpressing the epithelial sodium channel ß subunit exhibit spontaneous CF-like lung disease, including airway mucus obstruction and chronic inflammation. Here, we established a chronic CFRD-like model utilizing Scnn1b-Tg mice made diabetic by injection of streptozotocin. In Ussing chamber recordings of trachea, Scnn1b-Tg mice exhibited larger amiloride-sensitive currents and forskolin-activated currents, without a difference in ATP-activated currents compared to wildtype (WT) littermates. Both diabetic WT (WT-D) and diabetic Scnn1b-Tg (Scnn1b-Tg-D) mice on the same genetic background exhibited substantially elevated blood glucose at 8 weeks; glucose levels also were elevated in bronchoalveolar lavage fluid (BALF) Bulk lung RNA-seq data showed significant differences between WT-D and Scnn1b-Tg-D mice. Neutrophil counts in BALF were substantially increased in Scnn1b-Tg-D lungs compared to controls (Scnn1b-Tg-con) and compared to WT-D lungs. Lung histology data showed enhanced parenchymal destruction, alveolar wall thickening, and neutrophilic infiltration in Scnn1b-Tg-D mice compared to WT-D mice, consistent with development of a spontaneous lung infection. We intranasally administered Pseudomonas aeruginosa to induce lung infection in these mice for 24 hours, which led to severe lung leukocytic infiltration and an increase in pro-inflammatory cytokine levels in the BALF. In summary, we established a chronic CFRD-like lung mouse model using the Scnn1b-Tg mice. The model can be utilized for future studies toward understanding the mechanisms underlying the lung pathophysiology associated with CFRD and developing novel therapeutics.

Feasibility and accuracy of at-home glucose tolerance tests for cystic fibrosis related diabetes screening.

BACKGROUND: Adult people living with Cystic Fibrosis (CF) undergo annual screening for CF-related diabetes. These tests represent a burden and can lead to undesirable effects resulting in low adherence. The objectives of this study were to 1) compare gold-standard in-hospital oral glucose tolerance testing (OGTT) with at-home options, and 2) evaluate acceptability of at-home options. METHODS: A total of 34 adults living with CF undertook 3 types of OGTTs in standardized conditions within two weeks: 1) in a hospital using a 75 g glucose beverage, 2) at home with the same glucose beverage, and 3) at home using a standardized quantity of candy. Glucose levels were measured prior to the OGTT, after 1 and 2 hours. Concordance of glucose measurement, side effects and general appreciation were assessed across the three options. RESULTS: Mean blood glucose was comparable among the three tests. Glucose tolerance categorization (normal, impaired glucose tolerance, or diabetes) was concordant with the hospital reference test in 59 % of participants for the glucose beverage and 75 % for the candies. Side effects were mild with all types of OGTTs, and 94 % of participants preferred the home options. Among the at-home OGTTs, the glucose beverage was preferred to the candy option. CONCLUSIONS: Home-based OGTT could be an alternative to gold standard hospital-based OGTT testing, improving adherence to annual testing and reducing costs. However, the discrepancy between various OGTT testing methods could lead to diagnosis dilemma. This approach should be tested on a larger sample size.

Codevelopment of a model of care for adults living with cystic fibrosis-related diabetes.

BACKGROUND: Cystic fibrosis (CF) related diabetes affects up to half of all adults with CF and is associated with higher morbidity and mortality. Our aim is to codevelop an ideal model of care that integrates diabetes technology and better meets the needs of adults living with the condition to improve attendance, engagement, service satisfaction, and clinical outcomes. METHODS: Using qualitative research methods, we evaluated disease perceptions, barriers, and enablers to optimal CF-related diabetes management and service delivery. Integration of continuous glucose monitoring (CGM) was also explored. An initial broad purposive consumer survey was followed by focus groups with end-users. Grounded theory approach was utilized with major problem areas identified then explored, coded, and grouped into requisites for an "ideal model of care" for adults living with CF-related diabetes. RESULTS: Two key themes emerged (i) an ideal model of care consisted of a dual-specialty service co-led by endocrinology and CF physicians and supported by diabetes educator and CF dietitian with a goal to provide consistent and personalized diabetes management and (ii) CGM was acceptable for use in adults with CF-related diabetes with many perceived benefits and should be integrated into the model of care. Barriers to optimizing glycemic control included diet, finger-prick testing, reduced access to CGM, and pulmonary exacerbations. End-user feedback on CGM was overwhelmingly positive with regard to operability. CGM was also identified as a tool that could be used to engage, educate, and empower adults living with CF-related diabetes and facilitate constructive and personalized clinical decision-making by healthcare providers. CONCLUSION: For adults living with CF, a diagnosis of diabetes is associated with increased treatment burden. Our findings suggest an "ideal model of care" for CF-related diabetes would be co-led by endocrinology services integrated within a pre-existing CF service, incorporating CGM.

Racial inequities and rare CFTR variants: Impact on cystic fibrosis diagnosis and treatment.

Cystic fibrosis (CF) has been traditionally viewed as a disease that affects White individuals. However, CF occurs among all races, ethnicities, and geographic ancestries. The disorder results from mutations in the CF transmembrane conductance regulator (CFTR). Varying incidence of CF is reported among Black, Indigenous, and People of Color (BIPOC), who typically exhibit worse clinical outcomes. These populations are more likely to carry rare CFTR variants omitted from newborn screening panels, leading to disparities in care such as delayed diagnosis and treatment. In this study, we present a case-in-point describing an individual of Gambian descent identified with CF. Patient genotype includes a premature termination codon (PTC) (c.2353C>T) and previously undescribed single nucleotide deletion (c.1970delG), arguing against effectiveness of currently available CFTR modulator-based interventions. Strategies for overcoming these two variants will likely include combinations of PTC suppressors, nonsense mediated decay inhibitors, and/or alternative approaches (e.g. gene therapy). Investigations such as the present study establish a foundation from which therapeutic treatments may be developed. Importantly, c.2353C>T and c.1970delG were not detected in the patient by traditional CFTR screening panels, which include an implicit racial and ethnic diagnostic bias as these tests are comprised of mutations largely observed in people of European ancestry. We suggest that next-generation sequencing of CFTR should be utilized to confirm or exclude a CF diagnosis, in order to equitably serve BIPOC individuals. Additional epidemiologic data, basic science investigations, and translational work are imperative for improving understanding of disease prevalence and progression, CFTR variant frequency, genotype-phenotype correlation, pharmacologic responsiveness, and personalized medicine approaches for patients with African ancestry and other historically understudied geographic lineages.

Glycemic Variability and the Thickness of Retinal Layers in Cystic Fibrosis Patients with and without Cystic Fibrosis Related Diabetes.

PURPOSE: Patients with cystic fibrosis (CF) are at risk to develop CF related diabetes (CFRD) and subsequently even diabetic neuro- and/or vasculopathy. We sought to determine if there are typical signs of diabetes-related retinal alterations present in CF patients with preserved and impaired glycemic control. METHODS: During routine annual examination CF patients were offered an additional 7-day period of real time continuous glucose monitoring (rtCGM) and an ophthalmological examination including retinal optical coherence tomography (OCT). Patients were categorized according to the glycemic control, i.e. the results of an oral glucose tolerance test (OGTT) and rtCGM were taken into consideration. OCT data was analyzed by our previously published visual analysis software generating dedicated and spatially resolved deviation maps for visualization and quantification of differences in total retinal thickness and thickness of retinal nerve fiber layer (RNFL) as well as ganglion cell layer (GCL) in comparison to age-matched healthy controls and patients with either type 1 or type 2 diabetes mellitus. RESULTS: Results of the rtCGM and/or OGTT enabled discrimination between patients with normal glycemic control (CFNG; n = 6), with abnormal glycemic control (CFAG; n = 6) and overt CFRD (n = 4). OCT data indicates gradually increasing retinal thinning in all 3 groups, depending on the degree of glucose metabolism disorder compared to healthy controls. At the foveal region total retinal thickness and GCL thickness were significantly thinner in CFRD patients compared to CFNG patients (total retinal thickness: 260.4 µm (239.3-270.8) vs. 275.4 µm (254.3-289.5); GCL: 11.82 µm (11.16-15.25) vs. 17.30 µm (13.95-19.82); each p < 0.05). CONCLUSION: Although we investigated a rather small number of patients, we obtained evidence that intraretinal neurodegenerative changes occur in each of our subgroups (CFNG, CFAG, CFRD). Beyond this, our results favor the detrimental role of additional diabetes, as the deviations from healthy controls were most pronounced in the CFRD group and are similar to those seen in patients suffering from type 1 or type 2 diabetes.

Early-phase insulin secretion during mixed-meal tolerance testing predicts ß-cell function and secretory capacity in cystic fibrosis.

Insulin secretion within 30 minutes of nutrient ingestion is reduced in people with cystic fibrosis (PwCF) and pancreatic insufficiency and declines with worsening glucose tolerance. The glucose potentiated arginine (GPA) test is validated for quantifying ß-cell secretory capacity as an estimate of functional ß-cell mass but requires technical expertise and is burdensome. This study sought to compare insulin secretion during mixed-meal tolerance testing (MMTT) to GPA-derived parameters in PwCF. Methods: Secondary data analysis of CF-focused prospective studies was performed in PwCF categorized as 1) pancreatic insufficient [PI-CF] or 2) pancreatic sufficient [PS-CF] and in 3) non-CF controls. MMTT: insulin secretory rates (ISR) were derived by parametric deconvolution using 2-compartment model of C-peptide kinetics, and incremental area under the curve (AUC) was calculated for 30, 60 and 180-minutes. GPA: acute insulin (AIR) and C-peptide responses (ACR) were calculated as average post-arginine insulin or C-peptide response minus pre-arginine insulin or C-peptide under fasting (AIRarg and ACRarg), ~230 mg/dL (AIRpot and ACRpot), and ~340 mg/dL (AIRmax and ACRmax) hyperglycemic clamp conditions. Relationships of MMTT to GPA parameters were derived using Pearson's correlation coefficient. Predicted values were generated for MMTT ISR and compared to GPA parameters using Bland Altman analysis to assess degree of concordance. Results: 85 PwCF (45 female; 75 PI-CF and 10 PS-CF) median (range) age 23 (6-56) years with BMI 23 (13-34) kg/m2, HbA1c 5.5 (3.8-10.2)%, and FEV1%-predicted 88 (26-125) and 4 non-CF controls of similar age and BMI were included. ISR AUC30min positively correlated with AIRarg (r=0.55), AIRpot (r=0.62), and AIRmax (r=0.46) and with ACRarg (r=0.59), ACRpot (r=0.60), and ACRmax (r=0.51) (all P<0.001). ISR AUC30min strongly predicted AIRarg (concordance=0.86), AIRpot (concordance=0.89), and AIRmax (concordance=0.76) at lower mean GPA values, but underestimated AIRarg, AIRpot, and AIRmax at higher GPA-defined ß-cell secretory capacity. Between test agreement was unaltered by adjustment for study group, OGTT glucose category, and BMI. Conclusion: Early-phase insulin secretion during MMTT can accurately predict GPA-derived measures of ß-cell function and secretory capacity when functional ß-cell mass is reduced. These data can inform future multicenter studies requiring reliable, standardized, and technically feasible testing mechanisms to quantify ß-cell function and secretory capacity.

The Role of Continuous Glucose Monitoring in Detecting Early Dysglycemia and Clinical Outcomes in Patients with Cystic Fibrosis.

Cystic fibrosis-related diabetes (CFRD) is the most common comorbidity in patients with cystic fibrosis (CF). CFRD has been correlated with important clinical outcomes, including poor nutrition, reduced pulmonary function, and earlier mortality. However, clinical decline due to abnormalities of blood glucose (dysglycemia) begins early in CF, before the diagnosis of CFRD by the gold-standard oral glucose tolerance test (OGTT). Continuous glucose monitoring (CGM) has been validated in patients with CF and has been recognized as a valuable tool in detecting early glucose abnormalities in patients with CF. Several CGM parameters have been used to predict CFRD in some but not all studies, and there is no consensus regarding CGM use for diagnostic purposes. Thus, it remains a complementary test to OGTT in CFRD diagnosis. The aim of this review is to provide an update on the pathophysiological mechanisms of CFRD, recent advances in the use of CGM for CFRD screening, and the association between CGM measures and CF-related clinical outcomes.

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.

Novel time-saving OGTT sparing HbA1c-HOMA2 based algorithm for the diagnosis of cystic fibrosis-related diabetes.

AIMS: The diagnosis of cystic fibrosis-related diabetes (CFRD) faces several challenges. We propose a novel screening algorithm to alleviate the burden of cystic fibrosis (CF). METHODS: Through a retrospective cross-sectional single-centre study, HbA1c and HOMA2 indices were assessed in multiple models as alternative diagnostic tools from OGTT data. We sought to establish specific thresholds for CFRD screening with oral glucose tolerance test (OGTT) as gold standard. We evaluated various straightforward or sequential approaches, in terms of diagnostic accuracy while also quantify the potential reduction in OGTTs through these different methods. RESULTS: HOMA indices were recovered in 72 patients. We devised a composite index that combines HbA1c and HOMA-B: Diabetes Predicting Index in cystic fibrosis (DIPIc) = (HbA1c(%) × 3.455) - (HOMA-B(%) ×  0.020) - 19.294. This index yields the highest screening accuracy according to receiver-operating characteristics curves. Using a stepwise algorithm that incorporates DIPIc decreases the requirement for annual OGTTs. A CFRD exclusion cutoff less than -1.7445 (sensitivity 98 %), in conjunction with a CFRD diagnostic threshold greater than 0.4543 (specificity 98 %) allows for 71 % OGTT sparing. CONCLUSION: The composite index DIPIc is a suitable, less invasive screening method for CFRD, which enables to avoid many OGTTs.

Clinical and genetic risk factors for cystic fibrosis-related liver disease in Egyptian CF children: A single-center experience.

BACKGROUND: Cystic fibrosis (CF) is an autosomal recessive disease. It affects multiple organ systems, including the liver, leading to CF-related liver disease (CFLD). It was noted that CFLD in Egyptian children with CF is more common than in non-Egyptian people with CF (pwCF). This study aimed to determine the incidence of CFLD and the potential risk factors for developing CFLD in Egyptian children. The correlation between CFLD and the various genotypes prevalent in Egyptian CF children will be discussed. In addition, comparison of CFLD in Egyptian and non-Egyptian CF patients will be presented. METHODS: This cross-sectional study included 50 pwCF from Ain Sham University's Pediatric Pulmonology Clinic in Children's Hospital, Cairo, Egypt. The sweat chloride test and genetic studies were done at the time of diagnosis. Additionally, all subjects underwent detailed history taking, laboratory investigations, clinical assessment, and pelvic abdominal ultrasound for evaluation of hepatic involvement. RESULTS: One-third of the Egyptian children with CF were found to have liver disease. The following independent risk factors for developing CFLD were identified as: male sex, severe genetic mutation (class I and II), long duration of CF disease, early onset of the CF, pancreatic insufficiency, as well as history of meconium ileus. In addition, diabetes mellitus and severe lung disease were proven to significantly increase the risk of developing CFLD. CONCLUSION: CFLD is common in Egyptian pwCF. CFLD's risk factors are similar to other reported research from other countries in the region.

Pancreas and islet morphology in cystic fibrosis: clues to the etiology of cystic fibrosis-related diabetes.

Cystic fibrosis (CF) is a multi-organ disease caused by loss-of-function mutations in CFTR (which encodes the CF transmembrane conductance regulator ion channel). Cystic fibrosis related diabetes (CFRD) occurs in 40-50% of adults with CF and is associated with significantly increased morbidity and mortality. CFRD arises from insufficient insulin release from ß cells in the pancreatic islet, but the mechanisms underlying the loss of ß cell function remain understudied. Widespread pathological changes in the CF pancreas provide clues to these mechanisms. The exocrine pancreas is the epicenter of pancreas pathology in CF, with ductal pathology being the initiating event. Loss of CFTR function results in ductal plugging and subsequent obliteration. This in turn leads to destruction of acinar cells, fibrosis and fatty replacement. Despite this adverse environment, islets remain relatively well preserved. However, islet composition and arrangement are abnormal, including a modest decrease in ß cells and an increase in α, δ and γ cell abundance. The small amount of available data suggest that substantial loss of pancreatic/islet microvasculature, autonomic nerve fibers and intra-islet macrophages occur. Conversely, T-cell infiltration is increased and, in CFRD, islet amyloid deposition is a frequent occurrence. Together, these pathological changes clearly demonstrate that CF is a disease of the pancreas/islet microenvironment. Any or all of these changes are likely to have a dramatic effect on the ß cell, which relies on positive signals from all of these neighboring cell types for its normal function and survival. A thorough characterization of the CF pancreas microenvironment is needed to develop better therapies to treat, and ultimately prevent CFRD.

Pregnancy in women with cystic fibrosis and diabetes: An audit of outcomes at two tertiary obstetric hospitals in Australia in the pre-cystic fibrosis transmembrane conductance regulator modulator era.

Background: Pregnancy in women with cystic fibrosis (CF) is becoming more common. Long-term metabolic issues such as diabetes are also becoming more common and have potentially important impacts on pregnancy outcomes. This study aimed to assess the impact of diabetes on pregnancy outcomes for women with CF. Methods: We undertook a retrospective chart audit of pregnancies to women with CF at the two tertiary obstetric hospitals in Southeast Queensland associated with CF and transplant management clinics between 2006 and 2016. Results: A total of 38 pregnancies among 26 women were identified. Four women (five pregnancies) had cystic fibrosis-related diabetes (CFRD) diagnosed prior to pregnancy, and 12 women (15 pregnancies) developed gestational diabetes (GDM) complicating pregnancy. CFRD and GDM were associated with higher rates of delivery complications, prematurity, and the need for neonatal intensive care unit admission. Conclusion: Diabetes is common during pregnancy in women with CF and impacts pregnancy outcomes.

Effect of 18 months elexacaftor-tezacaftor-ivacaftor on body mass index and glycemic control in adults with cystic fibrosis.

BACKGROUND & AIMS: Malnutrition and cystic fibrosis related diabetes (CFRD) are common comorbidities in cystic fibrosis (CF). Cystic fibrosis transmembrane regulator (CFTR) modulators have shown beneficial effects on respiratory status. This study aims to determine the effect of elexacaftor-tezacaftor-ivacaftor (ETI) on body mass index (BMI) and glycemic control. METHODS: A retrospective, observational study of a cohort of 17 adult CF patients was conducted at the CF reference center of Ghent University Hospital. BMI evolution was analyzed 18 months before and 0, 3, 6, 12 and 18 months after the start of ETI. The evolution of insulin dependence and the 2 h oral glucose tolerance test (OGTT) results were described until 36 months after start of ETI, in a small subgroup of ten patients with CFRD or impaired glucose tolerance (IGT). RESULTS: A significant increase in mean BMI of 1.2 kg/m2 (±1.3 SD) was observed. Most weight gain was observed in the first 3 months after starting treatment. This effect was sustained during the observed period of 18 months. Six patients had insulin dependent CFRD, of which three were able to stop insulin after starting ETI. Two patients with CFRD treated with dietary measures showed an initial normalization of the 2 h OGTT, but deterioration at 36 month follow-up. CONCLUSIONS: After initiation of ETI an increase in BMI was observed in adults with CF. ETI can have a beneficial impact on glucose metabolism in patients with CFRD, leading to a possible need for reduction or cessation of insulin therapy.