Long-Term Efficacy and Tolerability of Acarbose Treatment in Patients with Type 2 Diabetes Mellitus

Effects of newer-generation anti-diabetics on diabetic retinopathy: a critical review

Diabetic retinopathy (DR) is the leading etiology of blindness in the working population of the USA. Its long-term management relies on effective glycemic control. Seven anti-diabetic classes have been introduced for patients with type 2 diabetes (T2D) in the past two decades, with different glucose-lowering and cardiovascular benefits. Yet, their effects specifically on DR have not been studied in detail. A systematic review of the literature was conducted to investigate this topic, focusing on the available clinical data for T2D. Published studies were evaluated based on their level of statistical evidence, as long as they incorporated at least one endpoint or adverse event pertaining to retinal health. Fifty nine articles met our inclusion criteria and were grouped per anti-diabetic class as follows: alpha-glucosidase inhibitors (1), peroxisome proliferator-activated receptor gamma (PPAR-γ) agonists (8), amylin analogs (1), glucagon-like peptide-1 (GLP-1) receptor agonists (28), dipeptidyl peptidase 4 (DPP-4) inhibitors (9), and sodium glucose co-transporter-2 (SGLT-2) inhibitors (9), plus one retrospective study and two meta-analyses evaluating more than one of the aforementioned anti-diabetic categories. We also reviewed publicly-announced results of trials for the recently-introduced class of twincretins. The available data indicates that most drugs in the newer anti-diabetic classes are neutral to DR progression; however, there are subclasses differences in specific drugs and T2D populations. In particular, there is evidence suggesting there may be worse diabetic macular edema with PPAR-gamma agonists, potential slight DR worsening with semaglutide (GLP-1 receptor agonist), and potential slight increase in the incidence of retinal vein occlusion in elderly and patients with advanced kidney disease receiving SGLT-2 inhibitors. All these warrant further investigation. Longer follow-up and systematic assessment of at least one DR-related endpoint are highly recommended for all future trials in the T2D field, to ultimately address this topic.

Acarbose With Comparable Glucose-Lowering but Superior Weight-Loss Efficacy to Dipeptidyl Peptidase-4 Inhibitors: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Background: Acarbose and dipeptidyl peptidase-4 inhibitors (DPP-4is) have several similarities regarding their efficacy. Assessing the hypoglycemic and weight-loss effects, as well as the tolerability between them at their optimal dosages, could provide a better management of adult type 2 diabetics. Methods: We performed a systematic review and network meta-analysis (NMA) on randomized controlled trials that were identified from the databases of EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, Web of Science, Conference Proceedings Citation Index, ClinicalTrials.gov, China National Knowledge Infrastructure, Wan Fang, and SinoMed. The trials with 300 mg/day of acarbose or the recommended doses of DPP-4is were the most optimal for our NMA. The mean differences (MD) and relative risk (RR) derived from eligible studies were used. Results: Among the 15,411 obtained potential studies, 13 pair-wise trials and 48 monotherapy studies were included in the meta-analysis and NMA, respectively. DPP-4is had a greater glucose-lowering effect, but a weaker weight-loss effect than acarbose in pair-wise meta-analysis (p < 0.05). However, NMA with 11,877 participants showed that, at their optimal doses, acarbose and DPP-4is had similar glucose-lowering effects on the 2-h postprandial glucose (MD 0.96 mmol/L, 95% credible interval -0.56 to 2.54), HbA1c (0.05%, -0.25 to 0.33), fasting plasma glucose reductions (-0.27 mmol/L, -0.76 to 0.24), and HbA1c < 7.0% target goal achievement (RR 1.33, 0.51 to 3.64). Acarbose was superior to DPP-4is regarding weight loss (MD -1.23 kg, -2.08 to -0.33). Acarbose had more withdrawal, gastrointestinal, and overall adverse events than DPP-4is (p < 0.05), but the differences disappeared after longer treatment (p > 0.05). Conclusions: Acarbose and DPP-4is have similar glucose-lowering effects, but the weight-loss effects of acarbose are superior. Therefore, in the use of the most optimal dosages, overweight/obese type 2 diabetics might benefit more from a treatment with acarbose than DPP-4is.

Risk of liver injury after α-glucosidase inhibitor therapy in advanced chronic kidney disease patients

Although α-glucosidase inhibitors (AGIs) are commonly used for controlling postprandial blood glucose, AGIs-induced liver injuries have been reported. However, the relationship between AGIs and liver injuries in advanced chronic kidney disease (CKD) patients remains unexplored. In this nationwide case-control study, we recruited 1765 advanced diabetic CKD patients, who received AGIs therapy from January 1, 2000 to December 31, 2010 as the study sample and 5295 matched controls. Recent and former AGIs users were defined as patients who received the AGIs prescription for 30–60 d and 30–210 d before the event of liver injury. The risk of AGIs-induced liver injury was examined using time-dependent Cox proportional hazards model. Liver injury occurred in 3.9% of patients in the study group and 3.3% of patients in the control group. AGIs use did not increase the risk of liver injury in advanced CKD patients (P = 0.19). The stratified analysis indicated no increased risk of liver injury in all AGIs-using subgroups (all P > 0.05). The available evidence supports extending the use of AGIs without increasing the risk of liver injury in patients with advanced CKD. Additional randomized controlled trials are warranted to confirm our results.

Novel 4-heteroaryl-antipyrines as DPP-IV inhibitors

Type 2 diabetes mellitus is a vast growing progressive disease that almost affects one person among every twelve globally. Regardless the availability of wide variety of oral hypoglycemics, only one-third of patients achieves proper glycemic control. With the advantage of the low risk of hypoglycemia, DPP-IV attracted the attention of medicinal chemists as a new target for oral hypoglycemics. In this report, a lead compound 1, with antipyrine scaffold, was obtained, and its binding mode was calculated. Several derivatives with bridged nitrogenous heterocycles have been synthesized via multicomponent reaction under controlled microwave heating conditions. The antidiabetic activity versus DPP-IV protein was evaluated and compared with sitagliptin. Compounds with smaller- or medium-sized nitrogenous bridges were comparable with sitagliptin in terms of DPP-IV inhibitory activity, potentially via targeting Glu203 and Glu204. The oral hypoglycemic activities of compounds with submicromolar IC50 values were further evaluated using diabetic mouse model.

Efficacy of acarbose in different geographical regions of the world: analysis of a real-life database

BACKGROUND

Alpha-glucosidase inhibitors are recommended in some international guidelines as first-line, second-line and third-line treatment options but are not used worldwide due to perceived greater effectiveness in Asians than Caucasians.

METHODS

Data from ten post-marketing non-interventional studies using acarbose, the most widely used alpha-glucosidase inhibitor, from 21 countries, provinces and country groups were pooled. Effects on glycated hemoglobin (HbA1c ) were analysed for four major ethnicity/region groups (European Caucasians and Asians from East, Southeast and South Asia) to identify differences in the response to acarbose.

RESULTS

The safety and efficacy populations included 67 682 and 62 905 patients, respectively. Mean HbA1c in the total population decreased by 1.12 ± 1.31% at the 3-month visit from 8.4% at baseline (p < 0.0001). Reductions in HbA1c , fasting plasma glucose and post-prandial plasma glucose were greater in patients with higher baseline values. Acarbose was well tolerated, with few episodes of hypoglycemia (0.03%) and gastrointestinal adverse events (2.76%). Data from 30 730 Caucasians from Europe and Asians from three major regions of Asia with non-missing gender/age information and baseline/3-month HbA1c data were analysed by multivariable analyses of covariance. After adjustment for relevant baseline confounding factors, Southeast and East Asians had slightly better responses to acarbose than South Asians and European Caucasians; however, the differences were small.

CONCLUSIONS

Acarbose was effective in both European Caucasians and Asians; however, after adjustment for baseline confounding factors, significant small differences in response favoured Southeast and East Asians.

On the potential of acarbose to reduce cardiovascular disease

In the emerging landscape of cardiovascular (CV) outcome trials evaluating the effects of blood glucose lowering drugs in individuals with type 2 diabetes, it is becoming increasingly apparent that since the promising signals coming from the United Kingdom Prospective Diabetes Study (UKPDS) no unequivocal benefits have been established for any single therapy thus far. There is an unmet need for introducing an effective pharmacological agent which could target both correlates of glycaemic regulation and CV risk factors, to ameliorate the enormous burden of fatal and non-fatal CV events in diabetic patients. Acarbose, like other alpha-glucosidase inhibitors (AGIs), has been proven to be an effective antidiabetic treatment for decades, but the overall significant impact of this class of drugs on modulating CV risk has only recently been appreciated. Accumulating evidence has shown that apart from its multiple effects on primarily postprandial glucose dysmetabolism, a key component of mechanisms linked to increased incidence of CV events, acarbose therapy also associates with a favorable impact on an array of surrogate markers of CV disease. Data stemming from in vitro testing of human cell lines as well as from preliminary trials in diabetic populations, like the Study to Prevent Non-Insulin-Dependent Diabetes Mellitus (STOP-NIDDM) trial, have highlighted – though not undisputed – the potential beneficial effects of the drug on CV morbidity. Large scale trials, like the ongoing Acarbose Cardiovascular Evaluation (ACE) trial, aim at conclusively establishing such a positive effect in patients with coronary heart disease and impaired glucose tolerance. In view of its usually acceptable level of side effects that are, if they occur, mostly limited to transient gastrointestinal symptoms, acarbose could well be a strong future player in CV disease secondary prevention. Current discouraging results from many trials of antidiabetic medications to significantly lower CV event rates in diabetic patients, should only draw further attention on alternative glucose lowering agents, among which acarbose is indeed promising.

The effect of dietary phytosphingosine on cholesterol levels and insulin sensitivity in subjects with the metabolic syndrome

BACKGROUND

Sphingolipids, like phytosphingosine (PS) are part of cellular membranes of yeasts, vegetables and fruits. Addition of PS to the diet decreases serum cholesterol and free fatty acid (FFA) levels in rodents and improves insulin sensitivity.

OBJECTIVE

To study the effect of dietary supplementation with PS on cholesterol and glucose metabolism in humans.

METHODS

Twelve men with the metabolic syndrome (MetS) (according to the International Diabetes Federation (IDF) criteria; age 51+/-2 years (mean+/-s.e.m.); body mass index (BMI) 32+/-1 kg/m(2)) were randomly assigned to 4 weeks of PS (500 mg twice daily) and 4 weeks of placebo (P) in a double-blind cross-over study, with a 4-week wash-out period between both interventions. At the end of each intervention anthropometric measures and serum lipids were measured and an intravenous glucose tolerance test (IVGTT) was performed.

RESULTS

Phytosphingosine did not affect body weight and fat mass compared with P. PS decreased serum total cholesterol (5.1+/-0.3 (PS) vs 5.4+/-0.3 (P) mmol/l; P<0.05) and low-density lipoprotein (LDL)-cholesterol levels (3.1+/-0.3 (PS) vs 3.4+/-0.3 (P) mmol/l; P<0.05), whereas it did not alter serum triglyceride and high-density lipoprotein (HDL)-cholesterol levels. In addition, PS lowered fasting plasma glucose levels (6.2+/-0.3 (PS) vs 6.5+/-0.3 (P) mmol/l; P<0.05). PS increased the glucose disappearance rate (K-value) by 9.9% during the IVGTT (0.91+/-0.06 (PS) vs 0.82+/-0.05 (P) %/min; P<0.05) at similar insulin levels, compared with P, thus implying enhanced insulin sensitivity. PS induced only minor gastrointestinal side effects.

CONCLUSION

Dietary supplementation of PS decreases plasma cholesterol levels and enhances insulin sensitivity in men with the MetS.