Congenital hyperinsulinism: current trends in diagnosis and therapy

Background

To investigate whether Stiff-person syndrome (SPS) and cerebellar ataxia (CA) are associated with distinct GAD65-Ab epitope specificities and neuronal effects.

Methods

Purified GAD65-Ab from neurological patients and monoclonal GAD65-Ab with distinct epitope specificities (b78 and b96.11) were administered in vivo to rat cerebellum. Effects of intra-cerebellar administration of GAD65-Ab were determined using neurophysiological and neurochemical methods.

Results

Intra-cerebellar administration of GAD65-Ab from a SPS patient (Ab SPS) impaired the NMDA-mediated turnover of glutamate, but had no effect on NMDA-mediated turnover of glycerol. By contrast, GAD65-Ab from a patient with cerebellar ataxia (Ab CA) markedly decreased the NMDA-mediated turnover of glycerol. Both GAD65-Ab increased the excitability of the spinal cord, as assessed by the F wave/M wave ratios. The administration of BFA, an inhibitor of the recycling of vesicles, followed by high-frequency stimulation of the cerebellum, severely impaired the cerebello-cortical inhibition only when Ab CA was used. Moreover, administration of transcranial direct current stimulation (tDCS) of the motor cortex revealed a strong disinhibition of the motor cortex with Ab CA. Monoclonal antibodies b78 and b96.11 showed distinct effects, with greater effects of b78 in terms of increase of glutamate concentrations, impairment of the adaptation of the motor cortex to repetitive peripheral stimulation, disinhibition of the motor cortex following tDCS, and increase of the F/M ratios. Ab SPS shared antibody characteristics with b78, both in epitope recognition and ability to inhibit enzyme activity, while Ab CA had no effect on GAD65 enzyme activity.

Conclusions

These results suggest that, in vivo, neurological impairments caused by GAD65-Ab could vary according to epitope specificities. These results could explain the different neurological syndromes observed in patients with GAD65-Ab.     

Analysis of GAD65 autoantibodies in Stiff-Person syndrome patients

Autoantibodies to the 65-kDa isoform of glutamate decarboxylase GAD65 (GAD65Ab) are strong candidates for a pathological role in Stiff-Person syndrome (SPS). We have analyzed the binding specificity of the GAD65Ab in serum and cerebrospinal fluid (CSF) of 12 patients with SPS by competitive displacement studies with GAD65-specific rFab-derived from a number of human and mouse mAbs specific for different determinants on the Ag. We demonstrate considerable differences in the epitope specificity when comparing paired serum and CSF samples, suggesting local stimulation of B cells in the CSF compartment of these patients. Moreover, these autoantibodies strongly inhibit the enzymatic activity of GAD65, thus blocking the formation of the neurotransmitter gamma-aminobutyric acid. The capacity of the sera to inhibit the enzymatic activity of GAD65 correlated with their binding to a conformational C-terminal Ab epitope. Investigation of the inhibitory mechanism revealed that the inhibition could not be overcome by high concentrations of glutamate or the cofactor pyridoxal phosphate, suggesting a noncompetitive inhibitory mechanism. Finally, we identified a linear epitope on amino acids residues 4-22 of GAD65 that was recognized solely by autoantibodies from patients with SPS but not by serum from type 1 diabetes patients. A mAb (N-GAD65 mAb) recognizing this N-terminal epitope was successfully humanized to enhance its potential therapeutic value by reducing its overall immunogenicity.     

Newly diagnosed latent autoimmune diabetes in adults (LADA) is associated with low level glutamate decarboxylase (GAD65) and IA-2 autoantibodies. Diabetes Incidence Study in Sweden (DISS).

A quantitative assay with microSepharose was used to determine GAD65Ab and IA-2Ab levels in 771 population-based patients diagnosed with diabetes mellitus at 15 to 34 years of age, and in 828 matched controls. Among the patients, 587 (76%) were classified with type I, 108 (14%) with type II, and 76 (10%) with unclassifiable diabetes. The levels above normal demonstrated a prevalence of GAD65Ab in 66% of type I diabetes, 50% of type II diabetes and 54% of unclassifiable patients and for IA-2Ab in 40%, 17% and 21%, respectively. Among the autoantibody-positive sera, the LADA patients had a lower GAD65Ab index (median 0.19, p < 0.0001) and IA-2Ab index (median 0.28, p < 0.0001) than the type I patients (median 0.37 and 0.66). Patients with unclassifiable diabetes had a GAD65Ab (median 0.43) or IA-2Ab (median 0.63) index which was not different from the type I diabetes patients. Our data demonstrate that young adult new-onset LADA patients have low level GAD65Ab and IA-2Ab. The low-level autoantibodies may signify a less aggressive beta-cell autoimmunity, which may explain why these patients are often classified with type II or non-insulin-dependent diabetes.     

Clinical characteristics, and time course of pancreatic beta-cell function and glutamic acid decarboxylase antibodies in Thai patients with adult-onset Type 1 diabetes: distinction between patients of rapid- and slow-onset.

In order to study the clinical characteristics, time course of beta cell function and glutamic acid decarboxylase antibodies (GAD65Ab) in Thai patients with adult-onset Type 1 diabetes and to examine the distinctive features between patients with rapid-and slow-onset, 61 Thai patients with Type 1 diabetes who had age of disease onset at or after 20 years were studied. All patients were treated with insulin at the time of study and had fasting C-peptide levels +/-0.33 nmol/l. Twenty-six (42.6%) were in rapid-onset and 35 (57.4%) were in slow-onset groups. Fourty-four of 61 (70.5%) were male. About three-fourths had body mass index (BMI) < 19 kg/m2 at the time of insulin therapy. Only 7 of 61 (11.5%) patients had ketoacidosis at first presentation. Five patients had associated autoimmune thyroid disease and 10 (16.7%) patients had family history of diabetes in first-degree relatives. GAD65Ab was positive in 31 patients (50.8%); 10 (38.5%) were in rapid-onset and 21 (60.0%) were in slow-onset groups. GAD65Ab particularly of high levels were persistently elevated during 3-4 years follow-up period. The persistence of GAD65Ab were not associated with changes in fasting C-peptide levels. At the time of insulin dependency, there were no distinctive clinical features between rapid- and slow-onset patients except higher fasting C-peptide (0.08+/-0.08 vs. 0.14+/-0.10 nmol/l; p = 0.023) and GAD65Ab levels (19.6+/-17.4 vs. 46.1+/-49.7 U/ml; p = 0.036) in slow-onset patients. Fasting C-peptide levels of patients in the latter group were also demonstrated to be higher after 3-4 years of follow-up. In conclusion, most Thai patients with adult-onset Type 1 diabetes in this study were male and had significant degree of weight loss and lean BMI prior to insulin therapy. The presence of GAD65Ab did not predict clinical features or rate of beta cell loss. Patients in rapid-onset group had lower fasting C-peptide and GAD65Ab levels than those of slow-onset group which confirms the slower process of beta cell failure in the latter.     

Development of glutamic acid decarboxylase 65 (GAD65) autoantibody assay using biotin-GAD65 fusion protein

We evaluated a biotin-glutamic acid decarboxylase 65 (GAD65)-based enzyme-linked immunosorbent assay (B-ELISA) to detect GAD65 autoantibodies (GAD65Ab) in 78 sera from individuals with newly diagnosed type 1 diabetes. The GAD65Ab index of patients with type 1 diabetes (mean value of GAD65Ab index of 1.891) was significantly higher than those in 50 sera from healthy control group (mean value of 0.068). The intra- and inter-assay coefficients of variation (CV) were calculated to be 1.042 and 10.703%, respectively. The specificity of the B-GAD65 ELISA was comparable to the standard radioimmunoassay (RIA) which is routinely used in the laboratory. We describe the optimal conditions of the binding kinetics from each assay-step for the detection of GAD65Ab using the WHO standard serum 97/550 as a model autoantibody serum. We concluded that incubation times of 15, 90, and 90 min for step 1 (pre-incubation of Biotin14-GAD65 with serum), step 2 (binding the Ab/Ag complex to NeutrAvidin plate), and step 3 (incubation with HRPO-anti-human IgG), respectively, along with human serum dilutions of 1:50, would provide an optimal assay signal within a relatively short timeframe.     

An analysis of the cross-reactivity of autoantibodies to GAD65 and GAD67 in diabetes

Background

Autoantibodies to GAD65 (anti-GAD65) are present in the sera of 70–80% of patients with type 1 diabetes (T1D), but antibodies to the structurally similar 67 kDa isoform GAD67 are rare. Antibodies to GAD67 may represent a cross-reactive population of anti-GAD65, but this has not been formally tested.

Methodology/Principal Findings

In this study we examined the frequency, levels and affinity of anti-GAD67 in diabetes sera that contained anti-GAD65, and compared the specificity of GAD65 and GAD67 reactivity. Anti-GAD65 and anti-GAD67 were measured by radioimmunoprecipitation (RIP) using ¹²⁵I labeled recombinant GAD65 and GAD67. For each antibody population, the specificity of the binding was measured by incubation with 100-fold excess of unlabeled GAD in homologous and heterologous inhibition assays, and the affinity of binding with GAD65 and GAD67 was measured in selected sera. Sera were also tested for reactivity to GAD65 and GAD67 by immunoblotting. Of the 85 sera that contained antibodies to GAD65, 28 contained anti–GAD67 measured by RIP. Inhibition with unlabeled GAD65 substantially or completely reduced antibody reactivity with both ¹²⁵I GAD65 and with ¹²⁵I GAD67. In contrast, unlabeled GAD67 reduced autoantibody reactivity with ¹²⁵I GAD67 but not with ¹²⁵I GAD65. Both populations of antibodies were of high affinity (>10¹⁰ l/mol).

Conclusions

Our findings show that autoantibodies to GAD67 represent a minor population of anti-GAD65 that are reactive with a cross-reactive epitope found also on GAD67. Experimental results confirm that GAD65 is the major autoantigen in T1D, and that GAD67 per se has very low immunogenicity. We discuss our findings in light of the known similarities between the structures of the GAD isoforms, in particular the location of a minor cross-reactive epitope that could be induced by epitope spreading.     

Comparison of the prevalence of glutamic acid decarboxylase (GAD65) and gliadin antibodies (AGA) in a randomly selected adult estonian population.

We aimed to test the hypothesis that gluten might be associated with the development of islet cell autoimmunity. A random sample of 200 persons (87 males, mean age 42.4 years) from Estonia including one patient with type I diabetes mellitus was studied. IgG-type glutamic acid decarboxylase (GAD65) antibodies were determined using radioligand-binding assay and IgG/IgA-type gliadin antibodies (AGA) by enzyme-linked immunosorbent assay. Generic HLA-DRB1* alleles were analyzed using a polymerase chain reaction. Although our results revealed the highest GAD65Ab index and a high IgA-type AGA in a person with diabetes, no correlation between GAD65Ab and AGA values was revealed among the other 199 persons (p > 0.05). There were also no differences between test values among persons with and without different HLA-DRB1* alleles (p > 0.05). In the GAD65Ab assay, one person (0.5 %; 95 % CI: 0 - 1.5) out of 199 exceeded the 99(th) centile of the GAD65Ab index. In summary, the present study does not confirm the possibility that there is a relationship between the immune reactivity against GAD65 and gliadin, at least in persons without type I DM.     

Characterization of continuous B‐cell epitopes in the N‐terminus of glutamate decarboxylase67 using monoclonal antibodies

Glutamate decarboxylase (GAD) is an autoantigen associated with the autoimmune disorders Type‐1 diabetes (T1D) and stiff‐person syndrome (SPS). The protein, being an essential enzyme involved in the production of the inhibitory neurotransmitter γ‐aminobutyric acid, exists in two isoforms, GAD67 and GAD65. Both isoforms may be targeted by autoantibodies in SPS and T1D patients, although SPS primarily is associated with the presence of GAD67 autoantibodies, whereas T1D mainly is associated with the presence of GAD65 autoantibodies. In this study, we describe antibody reactivity to overlapping GAD67 peptides covering the complete protein sequence by modified peptide enzyme‐linked immunosorbent assay in order to identify potential GAD67 epitopes using two monoclonal antibodies (mAbs). Both GAD67 mAbs showed reactivity to linear epitopes located at the N‐terminal end of GAD67. The epitopes of GAD mAb 1 and 2 were identified as the amino acid sequences NAGADPNTTN and TETDFSNLF, respectively, corresponding to amino acids 14–23 and 91–99. Fine mapping of the epitopes revealed that antibody reactivity was related to amino acid side‐chain functionality, rather than amino acid side‐chain specificity. Additionally, results suggested that non‐contact amino acids in the epitope structure were essential for antibody reactivity. The exact role of these amino acids remains to be determined, but they are thought to be involved in backbone hydrogen bonds or stabilization of the epitope structure. As only limited knowledge is available in relation to antigenic regions of GAD67, this study contributes to characterization of GAD67 epitopes and may be a first step in the development of peptide‐based therapeutics against SPS. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd.     

Efficacy and Safety of Insulin Degludec 200 U/mL and Insulin Degludec 100 U/mL in Patients with Type 2 Diabetes (Begin: Compare)

ObjectiveThe purpose of the present study was to provide clinical data on the efficacy and safety of insulin degludec (IDeg) 200 U/mL compared with IDeg 100 U/mL in patients with type 2 diabetes mellitus (T2DM) currently treated with basal insulin in combination with oral antidiabetic drugs.MethodsIn this 22-week, treat-to-target trial, eligible adult patients with T2DM were randomized 1:1 to IDeg 200 or IDeg 100 U/mL once daily (OD) (n = 186 and 187, respectively). The starting insulin dose was based on a 1:1 transfer of the total prerandomization basal insulin dose. The primary endpoint was change (%) from baseline in glycosylated hemoglobin A1C (A1C) after 22 weeks of treatment.ResultsA total of 373 subjects (mean age 59.8 years, A1C 8.2%, fasting plasma glucose 149.6 mg/dL [8.3 mmol/L], body mass index 33.3 kg/m²) were randomized. A1C reduction with IDeg 200 U/mL was noninferior to that of IDeg 100 U/mL (IDeg 200 U/mL – IDeg 100 U/mL estimated treatment difference: -0.11%, 95% confidence interval (CI): -0.28 to 0.05). Rates of overall confirmed hypoglycemia were low and similar between both formulations (5.17 and 5.66 events/patient-year of exposure [PYE] for IDeg 200 and 100 U/mL, respectively). Similarly, the rates of nocturnal confirmed hypoglycemia were low (1.27 and 1.70 events/PYE for 200 and 100 U/mL). In general, both IDeg formulations were well tolerated (respective rates of adverse events: 4.16 and 3.00 events/PYE for 200 and 100 U/mL).ConclusionThe 200 and 100 U/mL formulations of IDeg provide comparable and effective levels of glycemic control with similar, low rates of overall confirmed and nocturnal confirmed hypoglycemia. (Endocr Pract. 2014; 20:785-791)     

Suppressive effect of glutamic acid decarboxylase 65-specific autoimmune B lymphocytes on processing of T cell determinants located within the antibody epitope

Type 1 diabetes is a T cell-mediated disease in which B cells serve critical Ag-presenting functions. In >95% of type 1 diabetic patients the B cell response to the glutamic acid decarboxylase 65 (GAD65) autoantigen is exclusively directed at conformational epitopes residing on the surface of the native molecule. We have examined how the epitope specificity of Ag-presenting autoimmune B cell lines, derived from a type 1 diabetic patient, affects the repertoire of peptides presented to DRB1*0401-restricted T cell hybridomas. The general effect of GAD65-specific B cells was to enhance Ag capture and therefore Ag presentation. The enhancing effect was, however, restricted to T cell determinants located outside the B cell epitope region, because processing/presentation of T cell epitopes located within the autoimmune B cell epitope were suppressed in a dominant fashion. A similar effect was observed when soluble Abs formed immune complexes with GAD65 before uptake and processing by splenocytes. Thus, GAD65-specific B cells and the Abs they secrete appear to modulate the autoimmune T cell repertoire by down-regulating T cell epitopes in an immunodominant area while boosting epitopes in distant or cryptic regions.     

Improved in Planta Expression of the Human Islet Autoantigen Glutamic Acid Decarboxylase (GAD65)

The smaller isoform of the enzyme glutamic acid decarboxylase (GAD65) is a major islet autoantigen in autoimmune type 1 diabetes mellitus (T1DM). Transgenic plants expressing human GAD65 (hGAD65) are a potential means of direct oral administration of the islet autoantigen in order to induce tolerance and prevent clinical onset of disease. We have previously reported the successful generation of transgenic tobacco and carrot that express immunoreactive, full-length hGAD65. In the present study, we tested the hypothesis that the expression levels of recombinant hGAD65 in transgenic plants can be increased by targeting the enzyme to the plant cell cytosol and by mediating expression through the potato virus X (PVX) vector. By substituting the NH₂-terminal region of hGAD65 with a homologous region of rat GAD67, a chimeric GAD67_1-87/GAD65_88-585 molecule was expressed in transgenic tobacco plants. Immunolocalization analysis showed that immunoreactive GAD67/65 was found in the plant cell cytosol. By using a radio-immuno assay with human serum from a GAD65 autoantibody-positive T1DM patient, the highest expression level of the recombinant GAD67/65 protein was estimated to be 0.19% of the total soluble protein, compared to only 0.04% of wild-type hGAD65. Transient expression of wild-type, full-length hGAD65 in N. benthamiana mediated by PVX infection was associated with expression levels of immunoreactive protein as high as 2.2% of total soluble protein. This substantial improvement of the expression of hGAD65 in plants paves the way for immunoprevention studies of oral administration of GAD65-containing transgenic plant material in animal models of spontaneous autoimmune diabetes.     

Anti-idiotypic antibody specific to GAD65 autoantibody prevents type 1 diabetes in the NOD mouse

Overt autoantibodies to the smaller isoform of glutamate decarboxylase (GAD65Ab) are a characteristic in patients with Type 1 diabetes (T1D). Anti-idiotypic antibodies (anti-Id) directed to GAD65Ab effectively prevent the binding of GAD65 to GAD65Ab in healthy individuals. Levels of GAD65Ab-specific anti-Id are significantly lower in patients with T1D, leading to overt GAD65Ab in these patients. To determine the possible protective role of GAD65Ab-specific anti-Id in T1D pathogenesis, we developed the monoclonal anti-Id MAb 8E6G4 specifically targeting human monoclonal GAD65Ab b96.11. MAb 8E6G4 was demonstrated as a specific anti-Id directed to the antigen binding site of b96.11. MAb 8E6G4 recognized human antibodies in sera from healthy individuals, T2D patients, and T1D patients as established by ELISA. We confirmed these MAb 8E6G4-bound human antibodies to contain GAD65Ab by testing the eluted antibodies for binding to GAD65 in radioligand binding assays. These findings confirm that GAD65Ab are present in sera of individuals, who test GAD65Ab-negative in conventional detection assays. To test our hypothesis that GAD65Ab-specific anti-Id have an immune modulatory role in T1D, we injected young Non Obese Diabetic (NOD) mice with MAb 8E6G4. The animals were carefully monitored for development of T1D for 40 weeks. Infiltration of pancreatic islets by mononuclear cells (insulitis) was determined to establish the extent of an autoimmune attack on the pancreatic islets. Administration of MAb 8E6G4 significantly reduced the cumulative incidence rate of T1D and delayed the time of onset. Insulitis was significantly less severe in animals that received MAb 8E6G4 as compared to control animals. These results support our hypothesis that anti-Id specific to GAD65Ab have a protective role in T1D.     

Enzymatic characterization of a recombinant isoform hybrid of glutamic acid decarboxylase (rGAD67/65) expressed in yeast

BACKGROUND AND AIMS: Glutamic acid decarboxylase (GAD, EC 4.1.1.15) catalyses the conversion of glutamate to gamma-aminobutyric acid (GABA). The 65 kDa isoform, GAD65 is a potent autoantigen in type 1 diabetes, whereas GAD67 is not. A hybrid cDNA was created by fusing a human cDNA for amino acids 1-101 of GAD67 to a human cDNA for amino acids 96-585 of GAD65; the recombinant (r) protein was expressed in yeast and was shown to have equivalent immunoreactivity to mammalian brain GAD with diabetes sera. We here report on enzymatic and molecular properties of rGAD67/65. METHODS: Studies were performed on enzymatic activity of rGAD67/65 by production of 3H-GABA from 3H-glutamate, enzyme kinetics, binding to the enzyme cofactor pyridoxal phosphate (PLP), stability according to differences in pH, temperature and duration of storage, and antigenic reactivity with various GAD-specific antisera. RESULTS: The properties of rGAD67/65 were compared with published data for mammalian brain GAD (brackets). These included a specific enzyme activity of 22.7 (16.7) nKat, optimal pH for enzymatic activity 7.4 (6.8), K(m) of 1.3 (1.3) mM, efficient non-covalent binding to the cofactor PLP, and high autoantigenic potency. The stability of rGAD67/65 was optimal over 3 months at -80 degrees C, or in lyophilized form at -20 degrees C. CONCLUSIONS: Hybrid rGAD67/65 has enzymatic and other properties similar to those of the mixed isoforms of GAD in preparations from mammalian brain as described elsewhere, in addition to its previously described similar immunoreactivity.     

Epitope analysis of GAD65 binding in both cord blood and at the time of clinical diagnosis of childhood type 1 diabetes.

The GAD65 epitope immunoglobulin binding pattern in cord blood of children (n=37), who later developed type 1 diabetes at 3.2-14.9 years of age, was analyzed. First, the binding at diagnosis was compared with that in the cord blood serum. The next comparison was between the cord blood serum and the mothers' serum taken at delivery. Basal GAD65 binding levels were determined in Protein A Sepharose-based radiobinding assays with (35)S-labeled human and rat GAD65, rat GAD67 and GAD65/67 fusion proteins representing N-terminal (N), middle (M) and C-terminal (C) epitopes. In the first comparison, 28/37 children had GAD65 binding above 2.44 relative units (RU) (upper three quartiles), representing a marked increase from birth in the binding to human GAD65 (p<0.0001), rat GAD65 (p<0.0001), N- (p=0.04), M- (p<0.0001), C- (p=0.001), and M + C-epitopes (p<0.0001), but not to rat GAD67. At birth, 9/37 had GAD65 binding above 1.56 RU (upper quartile) demonstrating that their binding of human (35)S-GAD65 was higher in cord blood than in the mother (p=0.008). Higher cord blood binding was also observed for the N- (p=0.02) terminal epitope but not for rat GAD65, rat GAD67, and the remaining epitopes. These data suggest that differences in the epitope GAD65 binding between mother and child at birth are limited. In contrast, the epitope pattern at diagnosis differed from that at birth, supporting the view that disease-associated epitopes develop between birth and diagnosis.     

Cognitive decline in a patient with anti-glutamic acid decarboxylase autoimmunity; case report

Background  

Glutamic acid decarboxylase (GAD) is the rate-limiting enzyme for producing γ-aminobutyric acid, and it has been suggested that antibodies against GAD play a role in neurological conditions and type 1 diabetes. However, it is not known whether dementia appears as the sole neurological manifestation associated with anti-GAD antibodies in the central nervous system.     

Reduced Hypoglycemia and Comparable Efficacy with Insulin Glargine 300 U/ML Versus Insulin Glargine 100 U/ML in Patients with Type 2 Diabetes Achieving Different Levels of Prebreakfast Self-Monitored Plasma Glucose

Objective: To evaluate the efficacy and safety of insulin glargine 300 U/mL (Gla-300) and insulin glargine 100 U/mL (Gla-100) in patients with type 2 diabetes (T2D) who reached prebreakfast self-monitored plasma glucose (SMPG) levels <100 and <130 mg/dL.Methods: This was a post hoc analysis of insulin-naïve (EDITION 3, NCT01676220) and experienced (EDITION 2, NCT01499095) patients with uncontrolled T2D, randomized to 6 months of Gla-300 versus Gla-100 treatment. Endpoints included glycated hemoglobin A1c change, hypoglycemia incidence, and event rates. Separate comparisons were done for patients achieving prebreak-fast fasting glucose of <100 versus ≥100 mg/dL and <130 versus ≥130 mg/dL.Results: Efficacy did not differ significantly between treatments in either study. Overall, basal insulin doses were ~10% higher with Gla-300 versus Gla-100. EDITION 2: overall and documented (≤70 mg/dL) hypoglycemia rates were significantly lower with Gla-300 versus Gla-100 in all SMPG groups except <100 mg/dL; nocturnal hypoglycemia rates were significantly lower with Gla-300 in all SMPG groups. EDITION 3: overall hypoglycemia rates were significantly lower with Gla-300 in patients with SMPG ≥100 mg/dL and those with SMPG <130 mg/dL; documented hypoglycemia rates were significantly lower in all SMPG groups except ≥130 mg/dL. Nocturnal and nocturnal documented hypoglycemia rates did not differ by treatment group. Hypoglycemia incidence did not differ by treatment in any SMPG group.Conclusion: In patients with T2D initiating basal insulin or previously treated for ≥6 months with basal insulin, Gla-300 provides similar efficacy to Gla-100 and reduces risk of hypoglycemia for many patients, despite a ~10% higher insulin dose.Abbreviations: A1C = glycated hemoglobin A1c; ADA = American Diabetes Association; Gla-100 = insulin glargine 100 U/mL; Gla-300 = insulin glargine 100 U/mL; OAD = oral antidiabetes drug; SMPG = self-monitored plasma glucose; T2D = type 2 diabetes     

IMPROVED HBA1C,TOTAL DAILY INSULIN DOSE,AND TREATMENT SATISFACTION WITH INSULIN PUMP THERAPY COMPARED TO MULTIPLE DAILY INSULIN INJECTIONS IN PATIENTS WITH TYPE 2 DIABETES IRRESPECTIVE OF BASELINE C-PEPTIDE LEVELS

Objective: Fasting C-peptide levels are used to differentiate type 1 from type 2 diabetes (T2D), thereby determining eligibility for coverage of continuous subcutaneous insulin infusion (CSII) for patients with T2D.Methods: A total of 168 patients (74 female/94 male, aged 55.5 ± 9.7 years) were randomized to CSII, and 163 patients (77 female/86 male, aged 56.4 ± 9.5 years) were randomized to multiple daily injections (MDI) of insulin and grouped by baseline C-peptide level: group A (≤183 pmol/L [≤0.55 ng/mL]); group B (>183 pmol/L [>0.55 ng/mL]). At 6 months, the MDI group crossed over to CSII. Within- and between-group comparisons were recorded at 6 and 12 months in the entire group and separately for those patients aged ≥65 years.Results: CSII reduced hemoglobin A1c (A1c) equally in groups A (P = .0006, P = .0022) and B (P<.0001, P<.0001) at 6 and 12 months, respectively. There was an increase in weight in group A versus group B at 6 months but not 12 months (P<.03). CSII therapy reduced total daily dose (TDD) of insulin and improved treatment satisfaction similarly in groups A and B. The results for patients aged ≥65 years displayed a similar trend as the entire group.Conclusion: A1c, TDD of insulin, and treatment satisfaction improved for T2D patients using CSII versus MDI therapy, irrespective of baseline C-peptide level. A subgroup of patients aged ≥65 years displayed a similar trend. These results support abandoning C-peptide as a criterion for reimbursing CSII therapy in patients with diabetes.Abbreviations: A1c = hemoglobin A1c; CMS = Centers for Medicare and Medicaid Services; CSII = continuous subcutaneous insulin infusion; DTSQ = Diabetes Treatment Satisfaction Questionnaire; MDI = multiple daily injections; RCT = randomized controlled trials; T1D = type 1 diabetes; T2D = type 2 diabetes; TDD = total daily dose     

Hypoglycemia in the Elderly with Diabetes: A Growing Problem with Emerging Solutions

Hypoglycemia is the major side effect of insulin therapy. The elderly are especially vulnerable to episodes of hypoglycemia, and with greater risks of complications such as falls. Two new long-acting basal insulins, glargine-300 (Gla-300) and degludec, are associated with lower incidences of hypoglycemia than previously available basal insulins. One of them, Gla-300, was studied in the elderly and has a lower incidence of hypoglycemia in patients over 65 years old. These new data should be incorporated into decision making when treating the elderly patient with insulin, whether they have type 1 or 2 diabetes.Abbreviations:A1c = glycated hemoglobin A1cGla-100 = glargine 100 U/mLGla-300 = glargine 300 U/mLGLP-1 RA = glucagon-like peptide-1 receptor analogue     

Efficacy and Safety of Ideglira in Older Patients with Type 2 Diabetes

Objective: The efficacy and safety of insulin degludec/liraglutide (IDegLira) in older patients has not yet been reported. This analysis aimed to evaluate the efficacy and safety of IDegLira in patients aged ≥65 years.Methods: A post hoc analysis compared results of patients aged ≥65 versus <65 years from DUAL II, III, and V. These were 26-week, phase 3, randomized, twoarm parallel, treat-to-target trials in patients already taking injectable glucose-lowering agents. We evaluated 311 patients aged <65 and 87 patients aged ≥65 years from DUAL II, 326 patients <65 years and 112 patients ≥65 years from DUAL III, and 412 patients <65 years and 145 patients ≥65 years from DUAL V. Patients were randomized to IDegLira or insulin degludec (DUAL II), IDegLira or unchanged glucagon-like peptide 1–receptor agonist (GLP-1RA) (DUAL III), or IDegLira or IGlar U100 (DUAL V).Results: In patients ≥65 years, hemoglobin A1C decreased to a greater extent with IDegLira than with comparators (estimated treatment differences, -1.0% &lsqb;-1.5; -0.6]_{95% confidence interval &lsqb;CI]}, -0.8% &lsqb;-1.0; -0.5]_{95% CI}, and -0.9% &lsqb;-1.3; -0.6]95%CI) for DUAL II, V, and III, respectively; all P<.001). These mirrored results of patients <65 years of age. Hypoglycemia rates were lower with IDegLira versus basal insulin and higher versus unchanged GLP-1RA (estimated rate ratios, 0.5 &lsqb;0.2; 1.6]_{95% CI} &lsqb;P = .242]; 0.3 &lsqb;0.1; 0.5]_{95% CI} &lsqb;P<.001], and 11.8 &lsqb;3.3; 42.8]_{95% CI} &lsqb;P<.001] for DUAL II, V, and III, respectively).Conclusion: Patients aged ≥65 years on basal insulin or GLP-1RA can improve glycemic control with IDegLira, and it is well tolerated overall.Abbreviations: A1C = hemoglobin A1C; AE = adverse event; CI = confidence interval; Degludec = insulin degludec; EOT = end of trial; ETD = estimated treatment difference; FPG = fasting plasma glucose; GLP-1RA = glucagon-like peptide 1 receptor agonist; IDegLira = insulin degludec/liraglutide; IGlar U100 = insulin glargine 100 U/mL; SU = sulfonylurea; T2D = type 2 diabetes