Glucose-lowering therapy in type 2 diabetes. New hope after the EMPA-REG outcome trial

Relationship between high-sensitivity C-reactive protein and subclinical carotid atherosclerosis stratified by glucose metabolic status in Chinese adults

BACKGROUND

Atherosclerosis is an inflammatory disease. Many studies demonstrated that hyperglycemia is not only increased inflammatory response, but also is a cause of atherosclerosis, implying that glucose metabolic status may be an important stratification factor when analyzing the relationship between inflammatory levels and subclinical carotid atherosclerosis. The aim of the present study is to assess the relationship between inflammatory levels and subclinical carotid atherosclerosis, stratified by different glucose metabolic status in a general population.

METHODS

An assessment was performed in 7975 participants living in Tianjin, China. In the present study, we examined subclinical carotid atherosclerosis, as defined by increased carotid intima-media thickness [IMT] and plaques. Measurements were performed using a carotid artery B-mode ultrasound system. The glucose metabolic status was defined by the criteria of the American Diabetes Association, and high-sensitivity C-reactive protein (hs-CRP) as an inflammatory indicator, was measured by immunoturbidimetric assay. Multiple logistic models were used to assess a stratified relationship between hs-CRP levels and subclinical carotid atherosclerosis. Strata were defined according to glucose metabolic status.

RESULTS

The prevalence of increased IMT and plaques were 27.3% and 21.3%, respectively. The adjusted odds ratios (95% confidence interval) for IMT across hs-CRP quartiles were as follows: 1.00 (reference), 1.10(0.88-1.38), 1.08(0.86-1.35) and 1.32(1.06-1.66) in blood glucose-normal subjects; 1.00 (reference), 1.33(0.92-1.91), 1.33(0.93-1.91), and 1.59(1.10-2.30) in prediabetic subjects; 1.00 (reference), 0.94(0.54-1.62), 1.17(0.65-2.12) and 0.98(0.55-1.76) in diabetic subjects, respectively. Similar results were observed for plaques.

CONCLUSIONS

Our results suggest that inflammatory levels are differently related to subclinical carotid atherosclerosis by the different glucose metabolic status.

EMPA-REG and Other Cardiovascular Outcome Trials of Glucose-lowering Agents: Implications for Future Treatment Strategies in Type 2 Diabetes Mellitus

During the last decade, the armamentarium for glucose-lowering drugs has increased enormously by the development of DPP-4 inhibitors, GLP-1 receptor agonists and SGLT2 inhibitors, allowing individualization of antidiabetic therapy for patients with type 2 diabetes (T2DM). Some combinations can now be used without an increased risk for severe hypoglycemia and weight gain. Following a request of the US Food and Drug Administration, many large cardiovascular (CV) outcome studies have been performed in patients with longstanding disease and established CV disease. In the majority of CV outcome studies, CV risk factors were well controlled and a high number of patients were already treated with ACE inhibitors/angiotensin receptor blockers, statins and antiplatelet drugs. Most studies with insulin glargine and newer glucose-lowering drugs (saxagliptin, alogliptin, sitagliptin, lixisenatide) demonstrated safety of newer glucose-lowering agents but did not show superiority in the CV outcomes compared with placebo. By contrast, in the EMPA-REG OUTCOME (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 Diabetes Mellitus Patients) study, CV death, all-cause mortality, and hospitalization for heart failure were significantly decreased when empagliflozin was added instead of placebo to therapy for patients with high CV risk and T2DM already well treated with statins, glucose-lowering drugs, and blood pressure-lowering drugs as well as antiplatelet agents. In addition, renal endpoints including endstage renal disease were also significantly reduced when empagliflozin was added instead of placebo. Interestingly, the reduction of these clinically relevant end points was observed after a few months, making antiatherogenic effects an unlikely cause. The fact that the incidence of myocardial infarction (MI) and stroke were not reduced is in line with the hypothesis that hemodynamic factors in particular have contributed to the impressive improvement of the prognosis. To reduce the CV burden of patients with T2DM, drugs influencing factors involved in atherogenesis (eg, insulin resistance, chronic inflammation, increase of HDL, prothrombotic state) are more promising. The recent IRIS (Insulin Resistance Intervention after Stroke) study documented a significant reduction in stroke and MI when pioglitazone instead of placebo was given to nondiabetic patients presenting with both stroke/transient ischemic attack and insulin resistance, confirming results from the PROactive (Prospective Pioglitazone Clinical Trial in Macrovascular Events) study in patients with T2DM. Based on these new data, we suggest that the addition of both empagliflozin and pioglitazone to metformin might be the relative best option to reduce the high CV morbidity and mortality of patients with T2DM and already established CV complications. The very recent announcement that the CV outcome study with liraglutide (LEADER) also demonstrated a significant reduction of the composite endpoint (cardiovascular death, non-fatal myocardial infarction or non-fatal stroke) gives new hope for further beneficial treatment options for T2DM patients with established CVD.