Awadhesh Kumar Singh

Sodium-glucose co-transporter-2 inhibitors and euglycemic ketoacidosis: Wisdom of hindsight.

Sodium-glucose co-transporter-2 inhibitors (SGLT-2i) are newly approved class of oral anti-diabetic drugs, in the treatment of type 2 diabetes, which reduces blood glucose through glucouresis via the kidney, independent, and irrespective of available pancreatic beta-cells. Studies conducted across their clinical development program found, a modest reduction in glycated hemoglobin ranging from −0.5 to −0.8%, without any significant hypoglycemia. Moreover, head-to-head studies versus active comparators yielded comparable efficacy. Interestingly, weight and blood pressure reduction were additionally observed, which was not only consistent but significantly superior to active comparators, including metformin, sulfonylureas, and dipeptydylpeptide-4 inhibitors. Indeed, these additional properties makes this class a promising oral anti-diabetic drug. Surprisingly, a potentially fatal unwanted side effect of diabetic ketoacidosis has been noted with its widespread use, albeit rarely. Nevertheless, this has created a passé among the clinicians. This review is an attempt to pool those ketosis data emerging with SGLT-2i, and put a perspective on its implicated mechanism.

Dipeptidyl peptidase-4 inhibitors: Novel mechanism of actions.

The pharmacological actions of the glucagon-like peptide-1 receptor agonists (GLP-1RA) are largely predictable as they interact directly with GLP-1 receptors on beta cells to mediate their glucose lowering effects by increasing GLP-1 in pharmacological range and not at all dependent upon endogenous GLP-1 secretion. The mechanism of action of dipeptidyl peptidase-4 inhibitors (DPP-4I) are relatively less clear although classical mechanism is to inhibit the endogenous GLP-1 metabolism and thereby increasing GLP-1 level in the physiological range. DPP-4I also increase the half-life of GLP-1 to some extent by inhibiting their quick degradation by DPP enzyme ubiquitously present in the body. Interestingly, even with the effective blockade with currently existing DPP-4I, the half-life of GLP-1 only increases from 1 min to 5 min and therefore its residual time in plasma still remains pretty short. Intriguingly, this GLP-1 rise is so modest and so short-lived that it may be difficult to believe that this would sufficiently engage and activate the GLP-1 receptor in beta cell to produce significant insulinotropic effect. However, in clinical trials as well as in real life scenario, the anti-glycemic efficacies seen with DPP-4I are quite satisfactory and sometime very much competitive to GLP-1RA as evident from their head-to-head trials including meta-analysis. This efficacy outcome challenges the “only” GLP-1 dependent mechanism of glucose lowering and provokes an insight that other neuro-endocrine pathway may be playing a second fiddle. This review will collate those emerging concept and put a perspective as to how DPP-4I might be working though other pathway besides direct GLP-1 mediated receptor activation.

Incretin response in Asian type 2 diabetes: Are Indians different?

Incretin-based therapy has clearly emerged as one of the most sought out strategy in managing type 2 diabetes, primarily because they generally do not causes hypoglycemia and possess weight-neutral or weight losing properties. Efficacy-wise too, these agents, are more or less similar to commonly used drugs metformin and sulfonylureas. Interestingly, some studies recently suggested that glycemic response to these incretin-based therapies could also differ ethnicity-wise. Subsequently, meta-analysis from these studies also suggested that Asians may have better response to these incretin-based therapies. This review will be an attempt to critically analyze those studies available in literature and to address as to why East-Asians and South-Asians may have different incretin response compared to non-Asians.

Bariatric surgery and diabetes remission: Who would have thought it?

Type 2 diabetes mellitus (T2DM) and obesity are increasingly common and major global health problems. The Edmonton obesity staging system clearly pointed towards increased mortality proportionate to the severity of obesity. Obesity itself triggers insulin resistance and thereby poses the risk of T2DM. Both obesity and T2DM have been associated with higher morbidity and mortality and this calls for institution of effective therapies to deal with the rising trend of complications arising out of this dual menace. Although lifestyle changes form the cornerstone of therapy for both the ailments, sustained results from this modalities is far from satisfactory. While Look AHEAD (action for HEAalth in diabetes) study showed significant weight loss, reduction in glycated hemoglobin and higher remission rate of T2DM at 1st year following intensive lifestyle measures; recurrence and relapse rate bounced back in half of subjects at 4 years, thereby indicating that weight loss and glycemic control is difficult to maintain in the long term with lifestyle interventions. Same recurrence phenomenon was also observed with pharmacotherapy with rimonabant, sibutramine and orlistat. Bariatric surgery has been seen to associate with substantial and sustained weight loss in morbidly obese patients. Interestingly, bariatric surgeries also induce higher rates of short and long-term diabetes remission. Although the exact mechanism behinds this diabetes remission are not well understood; improved insulin action, beta-cell function and complex interplay of hormones in the entero-insular axis appears to play a major role. This article reviews the effectiveness of bariatric procedures on remission or improvement in diabetes and put a perspective on its implicated mechanisms.

Is gliclazide a sulfonylurea with difference? A review in 2016

ABSTRACT Sulfonylureas (SUs) remain the most commonly prescribed drug after metformin in the treatment of type 2 diabetes (T2DM), despite the availability of several newer agents. The primary reason of SUs being most popular is their quick glycemic response, time-tested experience and least cost. Although SUs are one amongst the several other second line agents after metformin in all major guidelines, the new Dutch type 2 guidelines specifically advise gliclazide as the preferred second line drug instead of SUs as a class. The World Health Organization (WHO) has also included gliclazide in their Model List of Essential Medicines 2013 motivated by its safety data in elderly patients. Specifically advising gliclazide may have been based on emerging evidence suggesting cardiovascular neutrality of gliclazide over other SUs. This prompted us to do a literature review of gliclazide efficacy and safety data compared to other SUs as well as oral anti-diabetic drugs.

SAVOR-TIMI to SUSTAIN-6: a critical comparison of cardiovascular outcome trials of antidiabetic drugs

ABSTRACT Introduction: Since the inception of mandatory cardiovascular (CV) safety outcome trial (CVOT) promulgated by US FDA in 2008, seven trials have so far been published with three different classes of antidiabetic drugs in type 2 diabetes mellitus (T2DM). This mini-review aims to critically analyse these CVOTs in terms of different outcomes achieved. Areas covered: An electronic search pertaining to the subject was conducted till September 2016. The three CVOT conducted with saxagliptin, alogliptin and sitagliptin respectively, found them to be CV-neutral. However, both saxagliptin and alogliptin showed an increase in hospitalization due to heart failure (hHF), while sitagliptin had no such signal. The trial conducted with empagliflozin (EMPA-REG) found it to be superior in reducing major adverse cardiac events (MACE). The CVOT conducted with lixisenatide (ELIXA) was CV-neutral, but both liraglutide (LEADER) and semaglutide (SUSTAIN-6) demonstrated superiority in reducing MACE. Expert commentary: While EMPA-REG had robust reduction in the CV-death, all-cause death and hHF, there was a discordant non-significant increase in silent myocardial infarction (MI) (assessed in approximately 50% of patients) and non-fatal stroke. LEADER had concordant reduction in all CV endpoints. SUSTAIN-6 had most robust reduction in 3P-MACE, although no reduction in the CV-death, all-cause death and hHF were observed.

Diabetes insipidus: The other diabetes.

Diabetes insipidus (DI) is a hereditary or acquired condition which disrupts normal life of persons with the condition; disruption is due to increased thirst and passing of large volumes of urine, even at night. A systematic search of literature for DI was carried out using the PubMed database for the purpose of this review. Central DI due to impaired secretion of arginine vasopressin (AVP) could result from traumatic brain injury, surgery, or tumors whereas nephrogenic DI due to failure of the kidney to respond to AVP is usually inherited. The earliest treatment was posterior pituitary extracts containing vasopressin and oxytocin. The synthetic analog of vasopressin, desmopressin has several benefits over vasopressin. Desmopressin was initially available as intranasal preparation, but now the oral tablet and melt formulations have gained significance, with benefits such as ease of administration and stability at room temperature. Other molecules used for treatment include chlorpropamide, carbamazepine, thiazide diuretics, indapamide, clofibrate, indomethacin, and amiloride. However, desmopressin remains the most widely used drug for the treatment of DI. This review covers the physiology of water balance, causes of DI and various treatment modalities available, with a special focus on desmopressin.

Dipeptidyl peptidase-4 inhibitors as add-on therapy to insulin: rationale and evidences

ABSTRACT Type 2 diabetes mellitus being a progressive disease will eventually require insulin therapy. While insulin therapy is the ultimate option, many patients still fall short of target glycemic goals. This could, perhaps be due to the fear, unwillingness and practical barriers to insulin intensification. Hypoglycemia, oedema and weight gain is another limitation. Newer therapies with dipeptidyl peptidase-4 (DPP-4) inhibitors and sodium-glucose co-transporter-2 (SGLT-2) inhibitors are exciting options as both classes do not cause hypoglycemia and are either weight neutral or cause weight loss. DPP-4 inhibitors are an appealing option as an add-on therapy to insulin especially in elderly and patients with renal impairment. Moreover, glucose-dependent insulinotropic polypeptide (GIP) mediated augmentation of glucagon by DPP-4 inhibitors could also protect against hypoglycemia. These collective properties make these class a potential add-on candidate to insulin therapy. This article will review the efficacy and safety of DPP-4 inhibitors as an add-on to insulin therapy.

Can anti-Mullerian hormone replace ultrasonographic evaluation in polycystic ovary syndrome? A review of current progress

Several studies over the past decade have now consistently indicated that the serum anti-Mullerian hormone (AMH) levels are at least 2–3-fold higher in the patients with polycystic ovary syndrome (PCOS), which also corresponds to the increased number of AMH producing preantral and small antral follicles. Moreover, AMH levels have been found to be associated in direct proportion to the follicle numbers per ovary or antral follicular count, assessed by the transvaginal ultrasound (TVS). Furthermore, AMH correlates directly with the rising serum testosterone and luteinizing hormone levels in PCOS. Hence, serum AMH in women with oligo-anovulation and/or hyperandrogenemia could indicate the presence of underlying PCOS, when reliable TVS is not feasible, or not acceptable, either due to the virginal status or psycho-social issue. In addition, the imaging quality of abdominal ultrasound is often impaired by obesity, which typically occurs in PCOS women. Indeed, PCOS occurs most commonly in young females who cannot be subjected to invasive TVS for various reasons; therefore, a desirable alternative to TVS is urgently required to diagnose the most prevalent endocrine abnormality of young women. This review will analyze the currently available evidence regarding the role of AMH in the diagnosis of PCOS.

Glucagon-like peptide 1 and dysglycemia: Conflict in incretin science

Although GLP-1 (glucagon like peptide-1) based therapies (GLP-1 agonists and dipeptidyl peptidase-4 inhibitors) is currently playing a cornerstone role in the treatment of type 2 diabetes, dilemma does exist about some of its basic physiology. So far, we know that GLP-1 is secreted by the direct actions of luminal contents on the L cells in distal jejunum and proximal ileum. However, there is growing evidence now, which suggest that other mechanism via “neural” or “upper gut” signals may be playing a second fiddle and could stimulate GLP-1 secretion even before the luminal contents have reached into the proximities of L cells. Therefore, the contribution of direct and indirect mechanism to GLP-1 secretion remains elusive. Furthermore, no clear consensus exists about the pattern of GLP-1 secretion, although many believe it is monophasic. One of the most exciting issues in incretin science is GLP-1 level and GLP-1 responsiveness. It is not exactly known as to what happens to endogenous GLP-1 with progressive worsening of dysglycemia from normal glucose tolerance to impaired glucose to frank diabetes and furthermore with increasing duration of diabetes. Although, conventional wisdom suggests that there may be a decrease in endogenous GLP-1 level with the worsening of dysglycemia, literature showed discordant results. Furthermore, there is emerging evidence to suggest that GLP-1 response can vary with ethnicity. This mini review is an attempt to put a brief perspective on all these issues.