Lack of Glycemic Legacy Effects in the Veterans Affairs Diabetes Trial

Remission of Type 2 Diabetes After Treatment With a High-Fiber, Low-Fat, Plant-Predominant Diet Intervention: A Case Series

Background: Prevalence of type 2 diabetes (T2D) is rising, and its burden on the healthcare system remains a challenge. Consumption of a plant-predominant diet is a promising approach for achieving remission, which has emerged as a therapeutic target. Objective: To establish feasibility of achieving T2D remission with a plant-predominant diet in a cohort of free-living individuals. Methods: Patients referred to a wellness clinic were treated with a low-fat, whole food, plant-predominant diet while receiving standard medical treatment. Included patients were adults, mostly elderly, with HbA1c > 6.5%, with or without use of antidiabetic medications. Results: N = 59 patients were included in this analysis, with mean age 71.5 years (range 41-89). Twenty-two (37%) patients achieved T2D remission. Mean differences showed a significant decrease post-lifestyle change (T2) compared to prior to lifestyle change (T1) for the following outcomes [least squares mean difference (95% CI)]: BMI [-2.6 (-4.8, -.3)] kg/m2; HbA1c [ -1.3 (-1.6, -1.0)] %; and fasting glucose [-29.6 (-41.8, -17.5)] mg/dL. No significant differences were observed for systolic or diastolic blood pressure, HDL, LDL, or triglycerides. Conclusion: A lifestyle-based treatment intervention promoting adherence to a plant-predominant diet and integrated as part of routine care can successfully achieve T2D remission in wellness clinic patients.

Vascular complications in prediabetes and type 2 diabetes: a continuous process arising from a common pathology

The term, "prediabetes", describes a state of hyperglycaemia that is intermediate between true normoglycaemia and the diagnostic cut-offs for indices of glycaemia that are used to diagnose type 2 diabetes. The presence of prediabetes markedly increases the risk of developing type 2 diabetes. Numerous randomized, controlled evaluations of various agents have demonstrated significant prevention or delay of the onset of type 2 diabetes in subjects with prediabetes. Intensive lifestyle interventions and metformin have been studied most widely, with the lifestyle intervention being more effective in the majority of subjects. The application of therapeutic interventions at the time of prediabetes to preserve long-term outcomes has been controversial, however, due to a lack of evidence relating to the pathogenic effects of prediabetes and the effectiveness of interventions to produce a long-term clinical benefit. Recent studies have confirmed that prediabetes, however defined, is associated with a significantly increased risk of macrovascular and microvascular complications essentially identical to those of diabetes, and also with subclinical derangements of the function of microvasculature and neurons that likely signify increased risk of compilations in future. Normoglycaemia, prediabetes and type 2 diabetes appear to be part of a continuum of increased risk of adverse outcomes. Long-term (25-30 years) post-trial follow up of two major diabetes prevention trials have shown that short-term interventions to prevent diabetes lead to long-term reductions in the risk of complications. These findings support the concept of therapeutic intervention to preserve long-term health in people with prediabetes before type 2 diabetes becomes established.

Targets for blood glucose: What have the trials told us

The challenges of diabetes treatment are to prevent or delay microangiopathic complications and macrovascular disease. Early, effective and sustained glycaemic control is advocated by all diabetes guidelines to mitigate the risks of prolonged hyperglycaemia. The post-hoc analyses of the large randomised glucose intervention trials and the long-term results of these trials have shown clearly that intensive glycaemic control may have more favourable cardiovascular effects when initiated earlier in the course of diabetes, particularly among in patients without cardiovascular disease. Based on the intervention trials a haemoglobin A1c level of less than 7.0% (<53 mmol/mol) is a generally accepted target to reduce microvascular disease and should be initiated early in the course of the diabetes. However, haemoglobin A1c targets should be individualised. Achieving a good glycaemic control without detrimental effect and preferably with benefit to the cardiovascular system and to renal function is an important challenge. When targeting a tight glycaemic control, avoidance of hypoglycaemia is crucial particularly in patients with coronary artery disease and in patients with heart failure. The cardiovascular outcomes trials performed to test the cardiovascular safety of the new glucose-lowering therapies offer compelling evidence in favour of the role of these drugs for cardiovascular prevention. Thus, both the glycaemic target and the choice of therapies should now be defined on an individual basis.

Legacy effect of intensive glucose control on major adverse cardiovascular outcome: Systematic review and meta-analyses of trials according to different scenarios

BACKGROUND

Early and intensive glycaemic control provides long-term protection against the development of microvascular complications, a phenomenon defined legacy effect. Whether a legacy effect of high glucose exists also on macrovascular endpoints is uncertain.

METHODS AND FINDINGS

We performed a systematic review of both randomized clinical trials (RCT)s and observational studies pertinent to the research question. We searched PubMed, Embase, Scopus and the Cochrane database up to January 31th 2020. Eligibility criteria for RCTs were: 1 - efficacy assessment of intensive glucose lowering treatment vs a less-stringent/conventional treatment; 2 - the inclusion of a post-active phase, observational follow-up; 3 - enrolment of patients with T1DM, pre-diabetes, and T2DM; and 4 - data report on major adverse cardiovascular events (MACE) incidence, which was the primary endpoint of this meta-analysis. We performed multiple meta-analyses of the available RCTs according to different scenarios considering the type of diabetes, diabetes duration, the presence of previous cardiovascular events, follow-up extension, and the incidence of MACE recorded only during the observational, post-active phase of the trials. Results from observational studies reporting the association between HbA1c levels during the first year after diabetes diagnosis and subsequent MACE incidence were also collected and are reported narratively. We included data from 7 RCTs and 40,346 patients. The intensive glucose-lowering approach significantly decrease the incidence of MACE compared with conventional treatment (OR 0.86, CI 0.77-0.96; p = 0.007) when considering all the available studies, with a more consistent effect (OR 0.73, CI 0.56-0.94; p = 0.01) in the case of RCTs enrolling patients with diabetes duration <10 years, and an even more pronounced protection (OR 0.64, 48 CI 0.48, 0.86; p = 0.003) when analysing only RCTs enrolling patients without previous cardiovascular events at baseline. Considering only RCTs with a post-trial follow-up >10 years also yielded a relevant beneficial effect of the intensive approach (OR 0.71, CI 0.57, 0.88; p = 0.002). On the other hand, no effect was observed (OR 0.99, CI 0.92, 1.06; p = 0.81) when considering only the events recorded during the post-active, observational phases of the trials. Observational studies showed that HbA1c values >6.5% or 7% during the first year of diabetes diagnosis are associated with a higher incidence of late MACE with increased risk ranging from 19 up to 64%, according to the different study design and HbA1c stratification.

CONCLUSIONS

These results support the recommendation regarding glucose-lowering treatment intensification in order to decrease the probability of having a macrovascular event in patients with short diabetes duration, no prevalent cardiovascular diseases, and long life-expectancy. On the other side, data from RCTs do not support the existence of a protective legacy effect on the macrovasculature beyond the period of intensive glycaemic treatment.

Long-term follow up of older people on diabetes medications: observational study using linked health databases

There is uncertainty about the long-term benefits and risks of diabetes medications in older people. We investigated differences in hypoglycaemia, cardiovascular disease (CVD) or mortality in older people according to diabetes medication, using linked national hospitalisation and mortality data from New Zealand. Adults aged ≥65 years dispensed diabetes medication in 2010 with a baseline glycated haemoglobulin (HbA1c) level (n=18099, mean age 73 years, 50% female) were included and stratified into four groups: metformin-only (42%); metformin-plus-other-oral-hypoglycaemic/s (27%); other-oral/s-only (11%); and any-insulin (20%). Time to first event was analysed with Cox models adjusted for sociodemographic factors; clinical history (prior hospitalisation for diabetes or CVD, and comorbidities); glycated haemoglobin; and CVD medications. Over 7-year follow up, 16% of participants experienced hypoglycaemia, 36% a CVD event and 31% died. Compared with metformin-only, insulin and other oral hypoglycaemic/s were associated with five- to 10-fold long-term increased risk of hypoglycaemia, and increased risk of CVD and death although adjusted survival curves showed no important separation between medication groups for CVD and death with the possible exception of insulin. Although confounding by indication is unable to be eliminated, this study raises further questions about the use of second-line diabetes medications in older people.