Severe Hypoglycemia and Impaired Awareness of Hypoglycemia Persist in People With Type 1 Diabetes Despite Use of Diabetes Technology: Results From a Cross-sectional Survey

OBJECTIVE

To determine how diabetes technologies, including continuous glucose monitoring (CGM) and automated insulin delivery (AID) systems, impact glycemic metrics, prevalence of severe hypoglycemic events (SHEs), and impaired awareness of hypoglycemia (IAH) in people with type 1 diabetes in a real-world setting within the U.S.

RESEARCH DESIGN AND METHODS

In this retrospective, observational study with cross-sectional elements, participants aged ≥18 years were enrolled from the T1D Exchange Registry/online community. Participants completed a one-time online survey describing glycemic metrics, SHEs, and IAH. The primary objective was to determine the proportions of participants who reported achieving glycemic targets (assessed according to self-reported hemoglobin A1c) and had SHEs and/or IAH. We performed additional subgroup analyses focusing on the impact of CGM and insulin delivery modality.

RESULTS

A total of 2,074 individuals with type 1 diabetes were enrolled (mean ± SD age 43.0 ± 15.6 years and duration of type 1 diabetes 26.3 ± 15.3 years). The majority of participants (91.7%) were using CGM, with one-half (50.8%) incorporating AID. Despite high use of diabetes technologies, only 57.7% reported achieving glycemic targets (hemoglobin A1c <7%). SHEs and IAH still occurred, with ∼20% of respondents experiencing at least one SHE within the prior 12 months and 30.7% (95% CI 28.7, 32.7) reporting IAH, regardless of CGM or AID use.

CONCLUSIONS

Despite use of advanced diabetes technologies, a high proportion of people with type 1 diabetes do not achieve glycemic targets and continue to experience SHEs and IAH, suggesting an ongoing need for improved treatment strategies.

VOCAL: An observational study of ivacaftor for people with cystic fibrosis and selected non-G551D-CFTR gating mutations

BACKGROUND

VOCAL was an observational study of the effect of long-term ivacaftor on real-world clinical outcomes and healthcare resource utilization (HCRU) in people with cystic fibrosis (pwCF) in Italy, the Netherlands, and the UK.

METHODS

pwCF aged ≥6 years with non-G551D-CFTR gating mutations were eligible. Prospective data were collected up to 48 months after enrollment; retrospective data were collected to ensure that 12 months of pre-ivacaftor data were available. Endpoints included absolute change from baseline in percent predicted forced expiratory volume in 1 second (ppFEV₁) and measures of nutritional status. Pulmonary exacerbation (PEx) rates, HCRU, and respiratory microbiology during ivacaftor treatment were compared with data from the 12-month period before initiation.

RESULTS

Seventy-three eligible pwCF were enrolled and received ivacaftor; 65 (89.0%) completed the study (48 [65.8%] completed ≥48 months of ivacaftor). During the first 6 months of ivacaftor, ppFEV₁, body mass index (BMI), and BMI-for-age z-score showed least-squares mean absolute improvements of 10.8 percentage points, 0.79 kg/m², and 0.54, respectively; improvements were maintained through 48 months. Rates of PEx, antibiotic use due to PEx, and hospitalization decreased by >50% during ivacaftor treatment compared with before ivacaftor. The number of respiratory cultures and sputum was lower post-ivacaftor, as was the percentage of pwCF with positive respiratory cultures for 3 of 9 pathogens evaluated (Pseudomonas aeruginosa, Aspergillus fumigatus, Stenotrophomonas maltophilia). Reported safety results were consistent with CF and ivacaftor's known safety profile.

CONCLUSIONS

These results demonstrate the positive long-term effectiveness of ivacaftor on clinical outcomes and HCRU in pwCF with non-G551D-CFTR gating mutations in real-world settings.

Real-World Long-Term Ivacaftor for Cystic Fibrosis in France: Clinical Effectiveness and Healthcare Resource Utilization

Introduction

Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that has demonstrated clinical benefits in phase 3 trials. We report results from a real-world study (BRIO) to assess the effectiveness of ivacaftor in people with cystic fibrosis (pwCF) in France.

Methods

BRIO was an observational study conducted at 35 centers in France. Both pwCF initiating ivacaftor treatment and those already taking ivacaftor were included and prospectively followed for 24 months. The primary objective was to evaluate the effect of ivacaftor on percent predicted forced expiratory volume in 1 s (ppFEV₁); secondary objectives were evaluating the effect of ivacaftor on clinical effectiveness, healthcare resource utilization (HCRU), and safety.

Results

A total of 129 pwCF were enrolled; 58.9% were aged < 18 years; 64.3% had a G551D-CFTR allele. Mean age at ivacaftor initiation was 19.1 years (range, 2–64 years); ppFEV₁ increased by a least squares mean of 8.49 percentage points in the first 6 months and was sustained through 36 months of ivacaftor use. Growth metrics increased during the first 12 months post-ivacaftor and remained stable. The rate of pulmonary exacerbations (PEx) decreased during the 12 months post-ivacaftor compared with the 12 months pre-ivacaftor; estimated rate ratios (95% CI) were 0.57 (0.43–0.75) for PEx events and 0.25 (0.13–0.48) for PEx requiring hospitalization. No new safety concerns were identified; no deaths occurred.

Conclusions

The results from this real-world study of ivacaftor usage in France were consistent with prior clinical trial outcomes, confirming the clinical effectiveness of ivacaftor, as well as an associated reduction in HCRU.

Supplementary Information

The online version contains supplementary material available at 10.1007/s41030-021-00158-5.

Real-World Outcomes of Ivacaftor Treatment in People with Cystic Fibrosis: A Systematic Review

Cystic fibrosis (CF) is a rare, progressive, multi-organ genetic disease. Ivacaftor, a small-molecule CF transmembrane conductance regulator modulator, was the first medication to treat the underlying cause of CF. Since its approval, real-world clinical experience on the use of ivacaftor has been documented in large registries and smaller studies. Here, we systematically review data from real-world observational studies of ivacaftor treatment in people with CF (pwCF). Searches of MEDLINE and Embase identified 368 publications reporting real-world studies that enrolled six or more pwCF treated with ivacaftor published between January 2012 and September 2019. Overall, 75 publications providing data from 57 unique studies met inclusion criteria and were reviewed. Studies reporting within-group change for pwCF treated with ivacaftor consistently showed improvements in lung function, nutritional parameters, and patient-reported respiratory and sino-nasal symptoms. Benefits were evident as early as 1 month following ivacaftor initiation and were sustained over long-term follow-up. Decreases in pulmonary exacerbations, Pseudomonas aeruginosa prevalence, and healthcare resource utilization also were reported for up to 66 months following ivacaftor initiation. In studies comparing ivacaftor treatment to modulator untreated comparator groups, clinical benefits similarly were reported as were decreases in mortality, organ-transplantation, and CF-related complications. The safety profile of ivacaftor observed in these real-world studies was consistent with the well-established safety profile based on clinical trial data. Our systematic review of real-world studies shows ivacaftor treatment in pwCF results in highly consistent and sustained clinical benefit in both pulmonary and non-pulmonary outcomes across various geographies, study designs, patient characteristics, and follow-up durations, confirming and expanding upon evidence from clinical trials.

Insulin degludec/liraglutide (IDegLira) was effective across a range of dysglycaemia and body mass index categories in the DUAL V randomized trial

This study assessed the efficacy of insulin degludec/liraglutide (IDegLira) vs insulin glargine U100 (IGlar) across categories of baseline glycated haemoglobin (HbA1c; ≤7.5%, >7.5% to ≤8.5% and >8.5%), body mass index (BMI; <30, ≥30 to <35 and ≥35 kg/m² ) and fasting plasma glucose (FPG; <7.2 and ≥7.2 mmol/L) in patients with type 2 diabetes (T2D) uncontrolled on basal insulin, using post hoc analyses of the DUAL V 26-week trial. With IDegLira, mean HbA1c was reduced across all baseline HbA1c (1.0%-2.5%), FPG (1.5%-1.9%) and BMI categories (1.8%-1.9%), with significantly greater reductions compared with IGlar U100. For all HbA1c, FPG and BMI categories, IDegLira resulted in weight loss and IGlar U100 in weight gain; hypoglycaemia rates were lower for IDegLira vs IGlar U100. More patients achieved HbA1c <7% with IDegLira than IGlar U100 across all HbA1c (59%-87% vs 31%-66%), FPG (71%-74% vs 40%-51%) and BMI categories (71%-73% vs 40%-54%). IDegLira improved glycaemic control and induced weight loss in patients with T2D previously uncontrolled on basal insulin, across the categories of baseline HbA1c, FPG or BMI that were tested.

Safety and efficacy of IDegLira titrated once weekly versus twice weekly in patients with type 2 diabetes uncontrolled on oral antidiabetic drugs: DUAL VI randomized clinical trial

AIMS

To compare the safety and efficacy of a simpler titration algorithm for insulin degludec/liraglutide (IDegLira) with that used in previous DUAL trials in insulin-naïve patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

This 32-week, open-label, non-inferiority trial randomized adults with type 2 diabetes uncontrolled on metformin ± pioglitazone to receive IDegLira, titrated either once weekly, based on the mean of 2 pre-breakfast plasma glucose (PG) readings (n = 210), or twice weekly, based on the mean of 3 pre-breakfast PG readings (n = 210).

RESULTS

Mean HbA1c decreased from 8.2% (65 mmol/mol) to 6.1% (43 mmol/mol) with once-weekly titration and from 8.1% (65 mmol/mol) to 6.0% (42 mmol/mol) with twice-weekly titration; non-inferiority was confirmed (estimated treatment difference: 0.12% [-0.04; 0.28]_95%CI , 1.30 mmol/mol [-0.41; 3.01]_95%CI ). Approximately 90% of patients achieved HbA1c < 7% in each arm. Mean fasting PG was similar after 32 weeks. Weight change was -1.0 kg vs -2.0 kg for once-weekly vs twice-weekly titration. Rates of severe or blood glucose-confirmed symptomatic hypoglycaemia were low in both arms: 0.16 events/patient-year of exposure (PYE) for once-weekly, 0.76 events/PYE for twice-weekly titration. Mean IDegLira dose at 32 weeks was 41 dose steps (41 U IDeg/1.48 mg Lira) for both arms. Overall adverse event rates were 207.8 and 241.3 events/100 PYE with once-weekly and twice-weekly titration, respectively.

CONCLUSION

A pragmatic titration algorithm with once-weekly adjustments based on 2 PG readings resulted in a safety and glycaemic efficacy profile similar to that with twice-weekly adjustments based on 3 preceding PG values in insulin-naïve patients.

A link between FTO, ghrelin, and impaired brain food-cue responsivity

Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N6-methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO "obesity-risk" rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N6-methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N6-methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans.

Peripheral activation of the Y2-receptor promotes secretion of GLP-1 and improves glucose tolerance

The effect of peptide tyrosine-tyrosine (PYY) on feeding is well established but currently its role in glucose homeostasis is poorly defined. Here we show in mice, that intraperitoneal (ip) injection of PYY3-36 or Y2R agonist improves nutrient-stimulated glucose tolerance and enhances insulin secretion; an effect blocked by peripheral, but not central, Y2R antagonist administration. Studies on isolated mouse islets revealed no direct effect of PYY3-36 on insulin secretion. Bariatric surgery in mice, enterogastric anastomosis (EGA), improved glucose tolerance in wild-type mice and increased circulating PYY and active GLP-1. In contrast, in Pyy-null mice, post-operative glucose tolerance and active GLP-1 levels were similar in EGA and sham-operated groups. PYY3-36 ip increased hepato-portal active GLP-1 plasma levels, an effect blocked by ip Y2R antagonist. Collectively, these data suggest that PYY3-36 therefore acting via peripheral Y2R increases hepato-portal active GLP-1 plasma levels and improves nutrient-stimulated glucose tolerance.

Regulation of hindbrain Pyy expression by acute food deprivation, prolonged caloric restriction, and weight loss surgery in mice

PYY is a gut-derived putative satiety signal released in response to nutrient ingestion and is implicated in the regulation of energy homeostasis. Pyy-expressing neurons have been identified in the hindbrain of river lamprey, rodents, and primates. Despite this high evolutionary conservation, little is known about central PYY neurons. Using in situ hybridization, PYY-Cre;ROSA-EYFP mice, and immunohistochemistry, we identified PYY cell bodies in the gigantocellular reticular nucleus region of the hindbrain. PYY projections were present in the dorsal vagal complex and hypoglossal nucleus. In the hindbrain, Pyy mRNA was present at E9.5, and expression peaked at P2 and then decreased significantly by 70% at adulthood. We found that, in contrast to the circulation, PYY-(1-36) is the predominant isoform in mouse brainstem extracts in the ad libitum-fed state. However, following a 24-h fast, the relative amounts of PYY-(1-36) and PYY-(3-36) isoforms were similar. Interestingly, central Pyy expression showed nutritional regulation and decreased significantly by acute starvation, prolonged caloric restriction, and bariatric surgery (enterogastroanastomosis). Central Pyy expression correlated with body weight loss and circulating leptin and PYY concentrations. Central regulation of energy metabolism is not limited to the hypothalamus but also includes the midbrain and the brainstem. Our findings suggest a role for hindbrain PYY in the regulation of energy homeostasis and provide a starting point for further research on gigantocellular reticular nucleus PYY neurons, which will increase our understanding of the brain stem pathways in the integrated control of appetite and energy metabolism.

Diet and gastrointestinal bypass-induced weight loss: the roles of ghrelin and peptide YY

OBJECTIVE

Bariatric surgery causes durable weight loss. Gut hormones are implicated in obesity pathogenesis, dietary failure, and mediating gastrointestinal bypass (GIBP) surgery weight loss. In mice, we determined the effects of diet-induced obesity (DIO), subsequent dieting, and GIBP surgery on ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). To evaluate PYY's role in mediating weight loss post-GIBP, we undertook GIBP surgery in PyyKO mice.

RESEARCH DESIGN AND METHODS

Male C57BL/6 mice randomized to a high-fat diet or control diet were killed at 4-week intervals. DIO mice underwent switch to ad libitum low-fat diet (DIO-switch) or caloric restriction (CR) for 4 weeks before being killed. PyyKO mice and their DIO wild-type (WT) littermates underwent GIBP or sham surgery and were culled 10 days postoperatively. Fasting acyl-ghrelin, total PYY, active GLP-1 concentrations, stomach ghrelin expression, and colonic Pyy and glucagon expression were determined. Fasting and postprandial PYY and GLP-1 concentrations were assessed 30 days postsurgery in GIBP and sham pair-fed (sham.PF) groups.

RESULTS

DIO progressively reduced circulating fasting acyl-ghrelin, PYY, and GLP-1 levels. CR and DIO-switch caused weight loss but failed to restore circulating PYY to weight-appropriate levels. After GIBP, WT mice lost weight and exhibited increased circulating fasting PYY and colonic Pyy and glucagon expression. In contrast, the acute effects of GIBP on body weight were lost in PyyKO mice. Fasting PYY and postprandial PYY and GLP-1 levels were increased in GIBP mice compared with sham.PF mice.

CONCLUSIONS

PYY plays a key role in mediating the early weight loss observed post-GIBP, whereas relative PYY deficiency during dieting may compromise weight-loss attempts.

Dominant role of the p110beta isoform of PI3K over p110alpha in energy homeostasis regulation by POMC and AgRP neurons

PI3K signaling is thought to mediate leptin and insulin action in hypothalamic pro-opiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, key regulators of energy homeostasis, through largely unknown mechanisms. We inactivated either p110alpha or p110beta PI3K catalytic subunits in these neurons and demonstrate a dominant role for the latter in energy homeostasis regulation. In POMC neurons, p110beta inactivation prevented insulin- and leptin-stimulated electrophysiological responses. POMCp110beta null mice exhibited central leptin resistance, increased adiposity, and diet-induced obesity. In contrast, the response to leptin was not blocked in p110alpha-deficient POMC neurons. Accordingly, POMCp110alpha null mice displayed minimal energy homeostasis abnormalities. Similarly, in AgRP neurons, p110beta had a more important role than p110alpha. AgRPp110alpha null mice displayed normal energy homeostasis regulation, whereas AgRPp110beta null mice were lean, with increased leptin sensitivity and resistance to diet-induced obesity. These results demonstrate distinct metabolic roles for the p110alpha and p110beta isoforms of PI3K in hypothalamic energy regulation.

Subject standardization, acclimatization, and sample processing affect gut hormone levels and appetite in humans

BACKGROUND & AIMS

Gut hormones represent attractive therapeutic targets for the treatment of obesity and type 2 diabetes. However, controversy surrounds the effects that adiposity, dietary manipulations, and bariatric surgery have on their circulating concentrations. We sought to determine whether these discrepancies are due to methodologic differences.

METHODS

Ten normal-weight males participated in a 4-way crossover study investigating whether fasting appetite scores, plasma acyl-ghrelin, active glucagon-like peptide-1 (GLP-1), and peptide YY3-36 (PYY3-36) levels are altered by study-induced stress, prior food consumption, and sample processing.

RESULTS

Study visit order affected anxiety, plasma cortisol, and temporal profiles of appetite and plasma PYY3-36, with increased anxiety and cortisol concentrations on the first study day. Plasma cortisol area under the curve (AUC) correlated positively with plasma PYY3-36 AUC. Despite a 14-hour fast, baseline hunger, PYY3-36 concentrations, temporal appetite profiles, PYY3-36 AUC, and active GLP-1 were affected by the previous evening's meal. Sample processing studies revealed that sample acidification and esterase inhibition are required when measuring acyl-ghrelin and dipeptidyl-peptidase IV inhibitor addition for active GLP-1. However, plasma PYY3-36 concentrations were unaffected by addition of dipeptidyl-peptidase IV.

CONCLUSIONS

Accurate assessment of appetite, feeding behavior, and gut hormone concentrations requires standardization of prior food consumption and subject acclimatization to the study protocol. Moreover, because of the labile nature of acyl-ghrelin and active GLP-1, specialized sample processing needs to be undertaken.

The role of peptide YY in appetite regulation and obesity

The last decade has witnessed a marked increase in our understanding of the importance of gut hormones in the regulation of energy homeostasis. In particular, the discovery that the gut hormone peptide YY 3-36 (PYY3-36) reduced feeding in obese rodents and humans fuelled interest in the role of PYY3-36 in body weight regulation. Pharmacological and genetic approaches have revealed that the Y2-receptor mediates the anorectic effects of PYY3-36 whilst mechanistic studies in rodents identified the hypothalamus, vagus and brainstem regions as potential sites of action. More recently, using functional brain imaging techniques in humans, PYY3-36 was found to modulate neuronal activity within hypothalamic and brainstem, and brain regions involved in reward processing. Several lines of evidence suggest that low circulating PYY concentrations predispose towards the development and or maintenance of obesity. Subjects with reduced postprandial PYY release exhibit lower satiety and circulating PYY levels that correlate negatively with markers of adiposity. In addition, mice lacking PYY are hyperphagic and become obese. Conversely, chronic PYY3-36 administration to obese rodents reduces adiposity, and transgenic mice with increased circulating PYY are resistant to diet-induced obesity. Moreover, there is emerging evidence that PYY3-36 may partly mediate the reduced appetite and weight loss benefits observed post-gastric bypass surgery. Taken together these findings, coupled with the retained responsiveness of obese subjects to the effects of PYY3-36, suggest that targeting the PYY system may offer a therapeutic strategy to help treat obesity.

Peptide YY

PURPOSE OF REVIEW

This review discusses recent studies examining the effects of peptide YY on energy homeostasis, highlights the emerging hedonic effects of peptide YY and evaluates the therapeutic potential of the peptide YY system.

RECENT FINDINGS

A role for exogenous PYY3-36 as an anorectic agent in obese humans and rodents has been established and weight loss effects demonstrated in obese rodents. New lines of evidence support a role for endogenous peptide YY in regulating energy homeostasis. The NPY-Y2 receptor mediates the anorectic actions of PYY3-36 with rodent studies implicating the hypothalamus, vagus and brainstem as key target sites. Functional imaging in humans has confirmed that PYY3-36 activates brainstem and hypothalamic regions. The greatest effects, however, were observed within the orbitofrontal cortex, a brain region involved in reward processing. Further evidence for a hedonic role for PYY3-36 is supported by rodent studies showing that PYY3-36 decreases the motivation to seek high-fat food. Rodent studies using selective Y2 agonists and strategies combining PYY3-36/Y2 agonists with other anorectic agents have revealed increased anorectic and weight-reducing effects.

SUMMARY

Peptide YY plays a role in the integrative regulation of metabolism. The emerging hedonic effects of peptide YY together with the weight-reducing effects observed in obese rodents suggest that targeting the peptide YY system may offer a therapeutic strategy for obesity.

Critical role for peptide YY in protein-mediated satiation and body-weight regulation

Dietary protein enhances satiety and promotes weight loss, but the mechanisms by which appetite is affected remain unclear. We investigated the role of gut hormones, key regulators of ingestive behavior, in mediating the satiating effects of different macronutrients. In normal-weight and obese human subjects, high-protein intake induced the greatest release of the anorectic hormone peptide YY (PYY) and the most pronounced satiety. Long-term augmentation of dietary protein in mice increased plasma PYY levels, decreased food intake, and reduced adiposity. To directly determine the role of PYY in mediating the satiating effects of protein, we generated Pyy null mice, which were selectively resistant to the satiating and weight-reducing effects of protein and developed marked obesity that was reversed by exogenous PYY treatment. Our findings suggest that modulating the release of endogenous satiety factors, such as PYY, through alteration of specific diet constituents could provide a rational therapy for obesity.