Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

Medical treatment of Cushing's disease with concurrent diabetes mellitus

Cushing's disease (CD) is a severe endocrine disorder characterized by chronic hypercortisolaemia secondary to an overproduction of adrenocorticotropic hormone (ACTH) by a pituitary adenoma. Cortisol excess impairs normal glucose homeostasis through many pathophysiological mechanisms. The varying degrees of glucose intolerance, including impaired fasting glucose, impaired glucose tolerance, and Diabetes Mellitus (DM) are commonly observed in patients with CD and contribute to significant morbidity and mortality. Although definitive surgical treatment of ACTH-secreting tumors remains the most effective therapy to control both cortisol levels and glucose metabolism, nearly one-third of patients present with persistent or recurrent disease and require additional treatments. In recent years, several medical therapies demonstrated prominent clinical efficacy in the management of patients with CD for whom surgery was non-curative or for those who are ineligible to undergo surgical treatment. Cortisol-lowering medications may have different effects on glucose metabolism, partially independent of their role in normalizing hypercortisolaemia. The expanding therapeutic landscape offers new opportunities for the tailored therapy of patients with CD who present with glucose intolerance or DM, however, additional clinical studies are needed to determine the optimal management strategies. In this article, we discuss the pathophysiology of impaired glucose metabolism caused by cortisol excess and review the clinical efficacy of medical therapies of CD, with particular emphasis on their effects on glucose homeostasis.

Management of Glucocorticoid-Induced Hyperglycemia

Glucocorticoids are potent immunosuppressive and anti-inflammatory drugs used for various systemic and localized conditions. The use of glucocorticoids needs to be weighed against their adverse effect of aggravating hyperglycemia in persons with diabetes mellitus, unmask undiagnosed diabetes mellitus, or precipitate glucocorticoid-induced diabetes mellitus appearance. Hyperglycemia is associated with poor clinical outcomes, including infection, disability after hospital discharge, prolonged hospital stay, and death. Furthermore, clear guidelines for managing glucocorticoid-induced hyperglycemia are lacking. Therefore, this consensus document aims to develop guidance on the management of glucocorticoid-induced hyperglycemia. Twenty expert endocrinologists, in a virtual meeting, discussed the evidence and practical experience of real-life management of glucocorticoid-induced hyperglycemia. The expert group concluded that we should be proactive in terms of diagnosis, management, and post-steroid care. Since every patient has different severity of underlying disease, clinical stratification would help understand patient profiles and determine the treatment course. Patients at home with pre-existing diabetes who are already on oral or injectable therapy can continue the same as long as they are clinically stable and eating adequately. However, depending on the degree of hyperglycemia, modification of doses may be required. Initiating basal bolus with correction regimen is recommended for patients in non-intensive care unit settings. For patients in intensive care unit, variable rate intravenous insulin infusion could be temporarily used, but under supervision of diabetes inpatient team, and patients can be transitioned to subcutaneous insulin once stable baseline assessment and continual evaluation are crucial for day-to-day decisions concerning insulin doses. Glycemic variability should be carefully monitored, and interventions to treat patients should also aim at achieving and maintaining euglycemia. Rational use of glucose-lowering drugs is recommended and treatment regimen should ensure maximum safety for both patient and provider. Glucovigilance is required as the steroids taper during transition, and insulin dosage should be reduced subsequently. Increased clinical and economic burden resulting from corticosteroid-related adverse events highlights the need for effective management. Therefore, these recommendations would help successfully manage GC-induced hyperglycemia and judiciously allocate resources.

Diabetes Mellitus Secondary to Cushing's Disease

Associated with important comorbidities that significantly reduce patients' overall wellbeing and life expectancy, Cushing's disease (CD) is the most common cause of endogenous hypercortisolism. Glucocorticoid excess can lead to diabetes, and although its prevalence is probably underestimated, up to 50% of patients with CD have varying degrees of altered glucose metabolism. Fasting glycemia may nevertheless be normal in some patients in whom glucocorticoid excess leads primarily to higher postprandial glucose levels. An oral glucose tolerance test should thus be performed in all CD patients to identify glucose metabolism abnormalities. Since diabetes mellitus (DM) is a consequence of cortisol excess, treating CD also serves to alleviate impaired glucose metabolism. Although transsphenoidal pituitary surgery remains the first-line treatment for CD, it is not always effective and other treatment strategies may be necessary. This work examines the main features of DM secondary to CD and focuses on antidiabetic drugs and how cortisol-lowering medication affects glucose metabolism.

Glucocorticoid-Induced Diabetes Mellitus: An Important but Overlooked Problem

Glucocorticoids are widely used as potent anti-inflammatory and immunosuppressive drugs to treat a wide range of diseases. However, they are also associated with a number of side effects, including new-onset hyperglycemia in patients without a history of diabetes mellitus (DM) or severely uncontrolled hyperglycemia in patients with known DM. Glucocorticoid-induced diabetes mellitus (GIDM) is a common and potentially harmful problem in clinical practice, affecting almost all medical specialties, but is often difficult to detect in clinical settings. However, scientific evidence is lacking regarding the effects of GIDM, as well as strategies for prevention and treatment. Similarly to nonsteroid-related DM, the principles of early detection and risk factor modification apply. Screening for GIDM should be considered in all patients treated with medium to high doses of glucocorticoids. Challenges in the management of GIDM stem from wide fluctuations in postprandial hyperglycemia and the lack of clearly defined treatment protocols. Together with lifestyle measures, hypoglycemic drugs with insulin-sensitizing effects are indicated. However, insulin therapy is often unavoidable, to the point that insulin can be considered the drug of choice. The treatment of GIDM should take into account the degree and pattern of hyperglycemia, as well as the type, dose, and schedule of glucocorticoid used. Moreover, it is essential to instruct the patient and/or the patient's family about how to perform the necessary adjustments. Prospective studies are needed to answer the remaining questions regarding GIDM.

Genetic basis of dyslipidemia in disease precipitation of coronary artery disease (CAD) associated type 2 diabetes mellitus (T2DM)

Type 2 diabetes mellitus (T2DM) and its complications are linked to environmental, clinical, and genetic factors. This review analyses the disorders of lipids and their genetics with respect to coronary artery disease (CAD) associated with T2DM. Cell organelles, hepatitis C-virus infection, reactive oxygen species produced in mitochondria, and defective insulin signaling due to the arrest of G1 phase to S phase transition of β-cells have significant roles in the precipitation of the diseases. Adiponectin is anti-inflammatory and anti-atherosclerotic and improves insulin resistance. Low-density lipoprotein (LDL) is atherosclerotic, and LDL-cholesterol in T2DM is associated with high-cardiovascular risk. Further, LDL cholesterol reduction significantly reduces cardiovascular morbidity and mortality. High-density lipoprotein (HDL) is also anti-atherosclerotic due to HDL associated paraoxonase-1 serum enzyme, which prevents LDL oxidative modifications and the development of CAD. Moreover, elevated apolipoprotein B and apolipoprotein A-I (ApoB/ApoA-I) ratio in plasma is also a risk factor for CAD. LDL receptor, adiponectin, and endocannabinoid receptor-1 genes are independently associated with CAD and T2DM. Polymorphism of Apo E2 (epsilon2) is a positive factor to increase the T2DM risk and Apo E4 (epsilon4) is a negative factor to reduce the disease risk. Taq 1B polymorphism of cholesterol ester transfer protein (CETP) gene contributes to the development of atherosclerosis, whereas haplotypes of APOA5, APOC3, APOC4, and APOC5 genes are in the same cluster and are independently associated with high plasma triglyceride level, CAD and T2DM. In conclusion, because various genes, LDLR, CETP, APOA5, Apo E, Apo B, and Apo A-I, are associated with the precipitation of CAD associated with T2DM, a personalized diet-gene intervention therapy may be advocated to reduce the disease precipitation.

Risk factors for the development of glucocorticoid-induced diabetes mellitus

AIMS

To evaluate the incidence of glucocorticoid-induced diabetes mellitus (GC-DM) by repeated measurements of the postprandial glucose and detect predictors for the development of GC-DM.

METHODS

Inpatients with rheumatic or renal disease who received glucocorticoid therapy were enrolled in this study. We compared the clinical and laboratory parameters of the GC-DM group with the non-GC-DM group and performed a multivariate analysis to identify risk factors.

RESULTS

During a four-week period, 84 of the 128 patients (65.6%) developed GC-DM. All patients were diagnosed based on the detection of postprandial hyperglycemia. The GC-DM group had an older age (65.2 vs. 50.4 years, p<0.0001), higher levels of fasting plasma glucose (93.3 vs. 89.0mg/dl, p=0.027) and HbA1c (5.78 vs. 5.50%, 39.7 vs. 36.6 mmol/mol, p=0.001) and lower eGFR values (54.0 vs. 77.1 ml/min/1.73 m(2), p=0.0003) than the non-GC-DM group. According to the multivariate analysis, an older age (more than or equal to 65 years), higher HbA1c level (more than or equal to 6.0%) and lower eGFR (<40 ml/min/1.73m(2)) were identified as independent risk factors for GC-DM (OR 2.95, 95% CI 1.15-7.92, OR: 3.05, 95% CI 1.11-9.21, OR: 3.42, 95% CI: 1.22-10.8, respectively). The risk ratio for the development of GC-DM in the patients with at least one of these three risk factors was 2.28. The dose of glucocorticoids was not statistically related to the development of GC-DM.

CONCLUSIONS

Patients with an older age, higher HbA1c level and lower eGFR require close monitoring for the development of GC-DM, regardless of the dose of glucocorticoids being administered.

Effects of 6-month sitagliptin treatment on metabolic parameters in diabetic patients taking oral glucocorticoids: a retrospective cohort study

Background

There are no guidelines for the treatment of diabetes in patients taking glucocorticoids. We studied to understand the effects of 6-month treatment with sitagliptin on metabolic parameters in diabetic patients taking glucocorticoids.

Methods

We retrospectively picked up patients who had been prescribed sitagliptin for 6 months during the continuous prescription of oral glucocorticoids between October 2010 and October 2013 by a chart-based analysis, and compared the data before the sitagliptin treatment with the data at 6 months after the sitagliptin treatment started.

Results

Fifteen patients were eligible for the analyses in our study. The plasma glucose and HbA1c levels were significantly reduced by the sitagliptin treatment. Furthermore, body weight significantly decreased. We found a significant and inverse correlation between the change in HbA1c levels and HbA1c levels at baseline. However, there was no significant correlation between the change in HbA1c levels and the daily glucocorticoid dose at baseline.

Conclusions

The present study demonstrated that sitagliptin significantly reduced plasma glucose, HbA1c and body weight. Further, sitagliptin was more effective to improve glycemic control in patients taking glucocorticoids with higher HbA1c levels, independently of the daily glucocorticoid dose.

Alogliptin improves steroid-induced hyperglycemia in treatment-naïve Japanese patients with chronic kidney disease by decrease of plasma glucagon levels

BACKGROUND

Chronic kidney disease (CKD) is a risk factor for end-stage renal failure and cardiovascular disease, and a strategy to counteract CKD must be established. CKD caused by immunological abnormalities is treated by steroids, frequently resulting in steroid diabetes. Although insulin is the most effective drug against steroid diabetes, administering it to patients can be difficult. Dipeptidyl peptidase-4 (DPP-4) inhibitors were developed for diabetes mellitus with a new mechanism of action. However, their efficacies and mechanisms of action for steroid diabetes are unclear.

MATERIAL AND METHODS

We studied 11 CKD patients treated with steroids admitted to our hospital (3 men and 8 women; age, 66.0 ± 15.9 years). DPP-4 inhibitor alogliptin was administered for steroid diabetes. Levels of markers related to glucose metabolism were measured before alogliptin treatment and after alogliptin treatment, before the prednisolone dose was reduced.

RESULTS

Alogliptin treatment significantly increased plasma glucagon-like peptide-1 (GLP-1) levels from 1.16 ± 1.71 pmol/L to 4.48 ± 1.53 pmol/L and significantly reduced levels of plasma glucose recorded 2 h after lunch and hemoglobin A1c (HbA1c). No significant differences were seen in insulin secretory ability of homeostasis model assessment (HOMA) (HOMA-β) and insulin resistance index of HOMA (HOMA-R) before and after alogliptin treatment. In contrast, alogliptin treatment significantly decreased plasma glucagon levels, from 116.1 ± 38.7 pg/mL to 89.6 ± 17.3 pg/mL. Moreover, there were significant correlations among HbA1c, GLP-1, and glucagon levels.

CONCLUSIONS

Alogliptin improves steroid-induced hyperglycemia by decrease of glucagon levels through an increase in plasma GLP-1 levels.

Sitagliptin counteracts seasonal fluctuation of glycemic control

AIM: To assess the effect of sitagliptin therapy on seasonal fluctuation of glycemic control in Japanese type 2 diabetic patients.

METHODS: Participating patients (age: 29-80 years) had been treated with conventional oral antidiabetic agents and/or diet and exercise therapy for over 6 mo. From December 2009, 35 patients were additionally prescribed oral sitagliptin starting from 50 mg once daily, while 19 patients taking α-glucosidase inhibitors were switched to sitagliptin. Twenty-four patients who refused sitagliptin formed the control group. Changes of mean monthly hemoglobin A_1c (HbA_1c) during the “winter holiday season” were compared between groups using Student’s t-test (2008-2009 vs 2009-2010). Statistical significance was accepted at P < 0.05. Multivariate analysis was performed to assess whether sitagliptin use was associated with deterioration or improvement of glycemic control.

RESULTS: Both add-on sitagliptin and switching from α-glucosidase inhibitors to sitagliptin prevented the seasonal deterioration of glycemic control and tended to improve HbA_1c. Multivariate analysis revealed that both adding and switching to sitagliptin were negatively correlated with deterioration of glycemic control. In 44 patients who continued sitagliptin therapy for another year, elevation of HbA_1c was suppressed without adverse effects.

CONCLUSION: Sitagliptin is a suitable oral agent for preventing deterioration of glycemic control during the winter holiday season.