Motherhood, apple pie, hemoglobin A(1C), and the DCCT

Similar HbA1c reduction and hypoglycaemia with variable- vs fixed-time dosing of basal insulin peglispro in type 1 diabetes: IMAGINE 7 study

AIMS

To compare 24-hour fixed-time basal insulin peglispro (BIL) dosing with 8- to 40-hour variable-time BIL dosing for glycaemic control and safety in patients with type 1 diabetes. Primary outcome was non-inferiority of BIL variable-time dosing compared with fixed-time dosing for glycated haemoglobin (HbA1c) change after 12-week treatment (margin = 0.4%).

MATERIALS AND METHODS

This Phase 3, open-label, randomized, cross-over study (N = 212) was conducted at 20 centres in the United States. During the 12-week lead-in phase, patients received BIL daily at fixed-times. Two 12-week randomized cross-over treatment phases followed, where patients received BIL dosed at either fixed- or variable-times. During the 4-week safety follow-up, patients received conventional insulins.

RESULTS

During the lead-in period, least-squares mean HbA1c decreased from 7.5% to 6.8%. For BIL, variable-time dosing was non-inferior to fixed-time dosing for HbA1c change [least-squares mean difference = 0.06%, 95% confidence interval (-0.01, 0.13)]. In both regimens, HbA1c increased slightly during the cross-over periods, but remained significantly below baseline. Variable- and fixed-time dosing regimens had similar rates of total hypoglycaemia (10.4 ± 0.62 and 10.5 ± 0.67 events/patient/30 days, P = .947) and nocturnal hypoglycaemia (1.3 ± 0.11 and 1.5 ± 0.13 events/patient/30days, P = .060). Comparable proportions of patients achieved HbA1c < 7.0% with variable- [91 (54.5%)] and fixed-time dosing [101 (60.5%)].

CONCLUSIONS

Treatment with BIL allows patients to use flexible dosing intervals from 8 to 40 hours. Glycaemic efficacy (HbA1c), glycaemic variability and hypoglycaemia are similar to fixed-time dosing, suggesting that BIL could potentially provide flexibility in dosing for patients who miss their daily basal insulin.

Hemoglobin A1C, mean glucose, and persistence of glycation ratios in insulin-treated diabetes

OBJECTIVE

Determine the relationship between mean glucose (MG), as assessed by continuous glucose monitoring (CGM), and hemoglobin A1c (A1C) in insulin-requiring adults in a clinical practice setting and examine the persistence of this relationship over time.

METHODS

In this retrospective record review in a diabetes practice, a linear regression model was developed using data sets from all patients with ≥1 available download of a Dexcom SevenPlus CGM device in which there was >50% utilization in the 60 days prior to a laboratory A1C. Persistence of the MG to A1C relationship was examined in patients with ≥2 data sets available.

RESULTS

A total of 139 patients had ≥1 data set available for evaluation, and 101 patients had ≥2 data sets (range, 2 to 6; total, 279). The slope of the MG versus A1C curve was 19.5 mg/dL for each 1% change in A1C, with an intercept of 17.7 mg/dL. Although 88% of the measured MG values were within 15% of the A1C-predicted MG, there was substantial variation in individuals, with differences as large as ±26%. The MG to A1C (MG:A1C) ratio, which is a measure of glycation, was normally distributed, with a median of 21.6. Spearman correlation coefficients for the MG:A1C ratio on repeated measures ranged from 0.52 to 0.73, demonstrating persistence.

CONCLUSION

The relationship between MG and A1C is linear in a population but can vary between individuals. The MG:A1C ratio was normally distributed, tended to persist in individuals over time, and thus could be useful to identify apparent high and low glycators. Glycemic goals may need to be modified in such patients.

Glucose variability and inner retinal sensory neuropathy in persons with type 1 diabetes mellitus

PurposeTo quantify early neuroretinal alterations in patients with type 1 diabetes mellitus (T1DM) and to assess whether glycemic variability contributes to alterations in neuroretinal structure or function.MethodsThirty patients with T1DM and 51 controls underwent comprehensive ophthalmic examination and assessment of retinal function or structure with frequency doubling perimetry (FDP), contrast sensitivity, dark adaptation, fundus photography, and optical coherence tomography (OCT). Diabetic participants wore a subcutaneous continuous glucose monitor for 5 days, from which makers of glycemic variability including the low blood glucose index (LGBI) and area under the curve (AUC) for hypoglycemia were derived.ResultsSixteen patients had no diabetic retinopathy (DR), and 14 had mild or moderate DR. Log contrast sensitivity for the DM group was significantly reduced (mean±SD=1.63±0.06) compared with controls (1.77±0.13, P<0.001). OCT analysis revealed that the inner temporal inner nuclear layer (INL) was thinner in patients with T1DM (34.9±2.8 μm) compared with controls (36.5±2.9 μm) (P=0.023), although this effect lost statistical significance after application of the Bonferroni correction for multiple comparisons. Both markers of glycemic variability, the AUC for hypoglycemia (R=-0.458, P=0.006) and LGBI (R=-0.473, P=0.004), were negatively correlated with inner temporal INL thickness.ConclusionsPatients with T1DM and no to moderate DR exhibit alterations in inner retinal structure and function. Increased glycemic variability correlates with retinal thinning on OCT imaging, suggesting that fluctuations in blood glucose may contribute to neurodegeneration.

Human adipose-derived stromal/stem cells protect against STZ-induced hyperglycemia: analysis of hASC-derived paracrine effectors

Adipose-derived stromal/stem cells (ASCs) ameliorate hyperglycemia in rodent models of islet transplantation and autoimmune diabetes, yet the precise human ASC (hASC)-derived factors responsible for these effects remain largely unexplored. Here, we show that systemic administration of hASCs improved glucose tolerance, preserved β cell mass, and increased β cell proliferation in streptozotocin-treated nonobese diabetic/severe combined immunodeficient mice. Coculture experiments combining mouse or human islets with hASCs demonstrated that islet viability and function were improved by hASCs following prolonged culture or treatment with proinflammatory cytokines. Analysis of hASC-derived factors revealed vascular endothelial growth factor and tissue inhibitor of metalloproteinase 1 (TIMP-1) to be highly abundant factors secreted by hASCs. Notably, TIMP-1 secretion increased in the presence of islet stress from cytokine treatment, while TIMP-1 blockade was able to abrogate in vitro prosurvival effects of hASCs. Following systemic administration by tail vein injection, hASCs were detected in the pancreas and human TIMP-1 was increased in the serum of injected mice, while recombinant TIMP-1 increased viability in INS-1 cells treated with interleukin-1beta, interferon-gamma, and tumor necrosis factor alpha. In aggregate, our data support a model whereby factors secreted by hASCs, such as TIMP-1, are able to mitigate against β cell death in rodent and in vitro models of type 1 diabetes through a combination of local paracrine as well as systemic effects.

Monitoring HIV-infected Patients with Diabetes: Hemoglobin A1c, Fructosamine, or Glucose?

BACKGROUND

Published studies report inappropriately low hemoglobin A1C (HbA1c) values that underestimate glycemia in HIV patients.

METHODS

We reviewed the charts of all HIV patients with diabetes mellitus (DM) at our clinic. Fifty-nine patients had HbA1c data, of whom 26 patients also had fructosamine data. We compared the most recent HbA1c to finger-stick (FS) glucose averaged over three months, and fructosamine to FS averaged over six weeks. Predicted average glucose (pAG) was calculated as reported by Nathan et al: pAG (mg/dL) = 28.7 × A1C% − 46.7. Data were analyzed using the Statistical Analysis System (SAS) and Kruskal–Wallis test.

RESULTS

HbA1c values underestimated (UE) actual average glucose (aAG) in 19% of these patients and overestimated (OE) aAG in 27%. HbA1c estimated aAG within the established range in only 54% of the patients. There were no statistical differences in the types of HIV medication used in patients with UE, OE, or accurately estimated (AE) glycemia. A Spearman correlation coefficient between HbA1c and aAG was r = 0.53 (P < 0.0001). Correlation between fructosamine and aAG was r = 0.47 (P = 0.016).

CONCLUSIONS

The correlations between HbA1c and aAG and between fructosamine and aAG were weaker than expected, and fructosamine was not more accurate than HbA1c.

The effect of long-term use of U-500 insulin via continuous subcutaneous infusion on durability of glycemic control and weight in obese, insulin-resistant patients with type 2 diabetes

OBJECTIVE

To evaluate the long-term efficacy and safety of U-500 insulin administered via continuous subcutaneous insulin infusion (CSII) in patients with insulin-resistant type 2 diabetes and high insulin requirements.

METHODS

We retrospectively reviewed the effects of U-500 insulin administered via CSII on durability of glycemic control (HbA1c), body weight, total daily insulin dose, and incidence of hypoglycemia in 59 patients with insulin-resistant type 2 diabetes (duration of treatment 1 to 9.5 years; mean treatment duration 49 months). All variables were analyzed by 1-way analysis of variance (ANOVA) from pre-U-500 baseline to time points from 3 to 114 months.

RESULTS

After 3 months of U-500 insulin use, hemoglobin A1c dropped significantly from a mean baseline of 8.3% to a mean value of 7.3% (P = .003), and this improvement was sustained for over 66 months of use. There was no significant overall change in body weight or total daily insulin dose over time with the use of U-500 insulin. For those subjects who did gain weight, there was a parallel increase in insulin dose that correlated with weight gain. The overall incidence of severe hypoglycemia was low over the study period, with a mean occurrence of 0.1 episodes per patient per year.

CONCLUSIONS

U-500 insulin is safe and effective for extended use (up to 9.5 years) in patients with insulin-resistant type 2 diabetes who require high insulin doses, and provides sustained glycemic control without causing excessive weight gain.

Glucose variability

The proposed contribution of glucose variability to the development of the complications of diabetes beyond that of glycemic exposure is supported by reports that oxidative stress, the putative mediator of such complications, is greater for intermittent as opposed to sustained hyperglycemia. Variability of glycemia in ambulatory conditions defined as the deviation from steady state is a phenomenon of normal physiology. Comprehensive recording of glycemia is required for the generation of any measurement of glucose variability. To avoid distortion of variability to that of glycemic exposure, its calculation should be devoid of a time component.