Metformin is an oral hypoglycemic agent which is most widely used as first-line therapy for type 2 diabetes. Metformin improves hyperglycemia by suppressing hepatic glucose production and increasing glucose uptake in muscle. Metformin also has been shown to reduce cardiovascular events in randomized controlled trials; however, the underlying mechanism remains to be established. Recent preclinical and clinical studies have suggested that metformin not only improves chronic inflammation through the improvement of metabolic parameters such as hyperglycemia, insulin resistance and atherogenic dyslipidemia, but also has a direct anti-inflammatory action. Studies have suggested that metformin suppresses inflammatory response by inhibition of nuclear factor κB (NFκB) via AMP-activated protein kinase (AMPK)-dependent and independent pathways. This review summarizes the basic and clinical evidence of the anti-inflammatory action of metformin and discusses its clinical implication.

Type 2 diabetes (T2DM) is characterized by insulin resistance and β-cell dysfunction. Although, in contrast to type 1 diabetes, insulin resistance is assumed to be a major pathophysiological feature of T2DM, T2DM never develops unless β-cells fail to compensate insulin resistance. Recent studies have revealed that a deficit of β-cell functional mass is an essential component of the pathophysiology of T2DM, implying that β-cell deficit is a common feature of both type 1 and type 2 diabetes. β-cell dysfunction is present at the diagnosis of T2DM and progressively worsens with disease duration. β-cell dysfunction is associated with worsening of glycemic control and treatment failure; thus, it is important to preserve or recover β-cell functional mass in the management of T2DM. Since β-cell regenerative capacity appears somewhat limited in humans, reducing β-cell workload appears to be the most effective way to preserve β-cell functional mass to date, underpinning the importance of lifestyle modification and weight loss for the treatment and prevention of T2DM. This review summarizes the current knowledge on β-cell functional mass in T2DM and discusses the treatment strategy for T2DM.

Diabetes is associated with a two to three-fold increase in risk of cardiovascular disease. However, intensive glucose-lowering therapy aiming at reducing HbA1c to a near-normal level failed to suppress cardiovascular events in recent randomized controlled trials. HbA1c reflects average glucose level rather than glycemic variability. In in vivo and in vitro studies, glycemic variability has been shown to be associated with greater reactive oxygen species production and vascular damage, compared to chronic hyperglycemia. These findings suggest that management of glycemic variability may reduce cardiovascular disease in patients with diabetes; however, clinical studies have shown conflicting results. This review summarizes the current knowledge on glycemic variability and oxidative stress, and discusses the clinical implications.

The efficacy of diabetes treatment should not be evaluated solely by HbA1c levels as they should also focus on patient-reported outcomes (PROs), such as patient satisfaction, wellbeing and quality of life. The Diabetes Treatment Satisfaction Questionnaire (DTSQ) has been developed to assess patient satisfaction with diabetes treatment. DTSQ has been translated into more than 100 languages and is widely used in many countries, since it is relatively easy to answer and is used for both patients with and without medical therapy. Novel therapeutic options, such as insulin analogs, incretin-based therapy and sodium-glucose cotransporter 2 (SGLT2) inhibitors, have been shown to improve patient satisfaction using DTSQ for assessments. DTSQ is not only used for comparisons between different medications or treatment strategies, but also can be used to assess the quality of diabetes care in clinical settings. This is important as an improvement in treatment satisfaction may enhance patients’ self-efficacy and adherence to therapy, leading to the achievement of long-term stable glycemic control and reduced risk of diabetic complications. In this review, we summarize the current topics in DTSQ, introducing our own experience, and discuss the role of PROs in diabetes treatment.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a novel class of oral hypoglycemic agents which increase urinary glucose excretion by suppressing glucose reabsorption at the proximal tubule in the kidney. SGLT2 inhibitors lower glycated hemoglobin (HbA1c) by 0.6–0.8% (6–8 mmol/mol) without increasing the risk of hypoglycemia and induce weight loss and improve various metabolic parameters including blood pressure, lipid profile and hyperuricemia. Recent cardiovascular (CV) outcome trials have shown the improvement of CV and renal outcomes by treatment with the SGLT2 inhibitors, empagliflozin, canagliflozin, and dapagliflozin. The mechanisms by which SGLT2 inhibitors improve CV outcome appear not to be glucose-lowering or anti-atherosclerotic effects, but rather hemodynamic effects through osmotic diuresis and natriuresis. Generally, SGLT2 inhibitors are well-tolerated, but their adverse effects include genitourinary tract infection and dehydration. Euglycemic diabetic ketoacidosis is a rare but severe adverse event for which patients under SGLT2 inhibitor treatment should be carefully monitored. The possibility of an increase in risk of lower-extremity amputation and bone fracture has also been reported with canagliflozin. Clinical trials and real-world data have suggested that SGLT2 inhibitors improve CV and renal outcomes and mortality in patients with type 2 diabetes (T2DM), especially in those with prior CV events, heart failure, or chronic kidney disease. Results of recent trials including individuals without diabetes may change the positioning of this drug as ″a drug for cardiorenal protection″. This review summarizes the potential of SGLT2 inhibitors and discusses their role in the treatment of T2DM.

Type 2 diabetes (T2DM) is characterized by insulin resistance and beta-cell dysfunction. Although insulin resistance is assumed to be a main pathophysiological feature of the development of T2DM, recent studies have revealed that a deficit of functional beta-cell mass is an essential factor for the pathophysiology of T2DM. Pancreatic fat contents increase with obesity and are suggested to cause beta-cell dysfunction. Since the beta-cell dysfunction induced by obesity or progressive decline with disease duration results in a worsening glycemic control, and treatment failure, preserving beta-cell mass is an important treatment strategy for T2DM. In this mini-review, we summarize the current knowledge on beta-cell mass, beta-cell function, and pancreas fat in obesity and T2DM, and we discuss treatment strategies for T2DM in relation to beta-cell preservation.