Contribution of glimepiride to basal-prandial insulin therapy in patients with type 2 diabetes

Beta-cell function in type 2 diabetic patients who failed to maintain good glycemic status with a combination of maximum dosages of metformin and sulfonylurea

Background: The aim of this study was to investigate beta-cell function and examine whether sulfonylureas (SUs) are still useful in patients with type 2 diabetes (T2DM) who failed to maintain optimal glycemic control with a combination of maximum dosages of metformin and SU. Method: T2DM who had HbA1c >8% during treatment with a combination of maximum dosages of metformin and SU were studied. After enrollment, the patients were assigned to continue maximum dosages of SU and metformin for 2 weeks and then underwent the first oral glucose tolerance test (OGTT), the Max-SU OGTT. After the Max-SU OGTT, SUs were discontinued for 4 weeks and the second OGTT, the Discont-SU OGTT, was performed. After the Discont-SU OGTT, the same SU was restarted at 25% of the maximum dosage (25%Max-SU). After taking 25%Max-SU for 4 weeks, the third OGTT, the 25%Max-SU OGTT, was performed. Metformin at the same dosage was continued throughout the study. Normal OGTT (NGT) subjects, matched for age and body mass index (BMI), were also studied. Results: There were 25 T2DM and 28 NGT subjects. There was no difference in age and BMI between the two groups. The beta-cell function during Max-SU was 0.1, which was higher than 0.06 during Discont-SU (p<0.001) and also higher than 0.09 during 25%Max-SU (p=0.269). The beta-cell function during 25%Max-SU was higher than during Discont-SU (p<0.001). The beta-cell function of the NGT group was 0.34 and higher than during Max-SU (p<0.001). Fasting capillary blood glucose (FCBG) levels during Discont-SU (14.2±3.7 mmol/L) were higher than during 25%Max-SU (12.3±3.4 mmol/L) and during Max-SU (10.3±2.4 mmol/L) (p<0.05). In addition, the FCBG during Discont-SU was higher than that during 25%Max-SU (p<0.05). Conclusion: In T2DM patients who failed to achieve glycemic control with a combination of maximum dosages of metformin and SU, the beta-cell function declined compared to NGT subjects. However, the beta-cells were still responsive to SUs, which play a significant role in glycemic control.

Multifactorial intervention for diabetes control among older users of insulin

OBJECTIVE

To evaluate if the closer follow-up with the supply of insulin pens and the measurement of capillary blood glucose improve the management of older patients with type 2 diabetes without adequate glycemic control despite extensive therapy.

METHODS

This is a prospective, non-randomized, quasi-experimental study. We have included 45 patients over 60 years old, from both sexes, with glycated hemoglobin (HbA1c) > 8.5% using oral hypoglycemic agents and insulin. The intervention consisted of monthly medical visits, with the provision of insulin pens and strips for blood glucose measurement. All patients received insulin pen, refills of Neutral Protamine Hagedorn and regular insulin, needles for the pen, blood glucose meter, and capillary blood glucose tests (three tests/day). Treatment was adjusted with the same endocrinologist monthly for six months. Glycated hemoglobin was measured at baseline and 12 and 24 weeks after intervention.

RESULTS

Glycated hemoglobin at baseline was 10.34% (SE = 0.22%) and 8.54% (SE = 0.24%, p < 0.001) and 8.09% (SE = 0.21%, p < 0.001) at 12 and 24 weeks after intervention, respectively, with a significant reduction from baseline.

CONCLUSIONS

More frequent medical visits, with treatment inputs including the use of insulin pens and self-monitoring, have improved glycemic control (reduction of 2.25% in HbA1C, on average, at 24 weeks of follow-up). Our data support a change in the management and medical behavior of older patients with chronically decompensated diabetes.

Insulin monotherapy compared with the addition of oral glucose-lowering agents to insulin for people with type 2 diabetes already on insulin therapy and inadequate glycaemic control

BACKGROUND

It is unclear whether people with type 2 diabetes mellitus on insulin monotherapy who do not achieve adequate glycaemic control should continue insulin as monotherapy or can benefit from adding oral glucose-lowering agents to the insulin therapy.

OBJECTIVES

To assess the effects of insulin monotherapy compared with the addition of oral glucose-lowering agents to insulin monotherapy for people with type 2 diabetes already on insulin therapy and inadequate glycaemic control.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) and reference lists of articles. The date of the last search was November 2015 for all databases.

SELECTION CRITERIA

Randomised controlled clinical trials of at least two months' duration comparing insulin monotherapy with combinations of insulin with one or more oral glucose-lowering agent in people with type 2 diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials, assessed risk of bias, extracted data and evaluated overall quality of the evidence using GRADE. We summarised data statistically if they were available, sufficiently similar and of sufficient quality. We performed statistical analyses according to the statistical guidelines in the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

We included 37 trials with 40 treatment comparisons involving 3227 participants. The duration of the interventions ranged from 2 to 12 months for parallel trials and two to four months for cross-over trials.The majority of trials had an unclear risk of bias in several risk of bias domains. Fourteen trials showed a high risk of bias, mainly for performance and detection bias. Insulin monotherapy, including once-daily long-acting, once-daily intermediate-acting, twice-daily premixed insulin, and basal-bolus regimens (multiple injections), was compared to insulin in combination with sulphonylureas (17 comparisons: glibenclamide = 11, glipizide = 2, tolazamide = 2, gliclazide = 1, glimepiride = 1), metformin (11 comparisons), pioglitazone (four comparisons), alpha-glucosidase inhibitors (four comparisons: acarbose = 3, miglitol = 1), dipeptidyl peptidase-4 inhibitors (DPP-4 inhibitors) (three comparisons: vildagliptin = 1, sitagliptin = 1, saxagliptin = 1) and the combination of metformin and glimepiride (one comparison). No trials assessed all-cause mortality, diabetes-related morbidity or health-related quality of life. Only one trial assessed patients' treatment satisfaction and showed no substantial differences between the addition of either glimepiride or metformin and glimepiride to insulin compared with insulin monotherapy.Insulin-sulphonylurea combination therapy (CT) compared with insulin monotherapy (IM) showed a MD in glycosylated haemoglobin A1c (HbA1c) of -1% (95% confidence interval (CI) -1.6 to -0.5); P < 0.01; 316 participants; 9 trials; low-quality evidence. Insulin-metformin CT compared with IM showed a MD in HbA1c of -0.9% (95% CI -1.2 to -0.5); P < 0.01; 698 participants; 9 trials; low-quality evidence. We could not pool the results of adding pioglitazone to insulin. Insulin combined with alpha-glucosidase inhibitors compared with IM showed a MD in HbA1c of -0.4% (95% CI -0.5 to -0.2); P < 0.01; 448 participants; 3 trials; low-quality evidence). Insulin combined with DPP-4 inhibitors compared with IM showed a MD in HbA1c of -0.4% (95% CI -0.5 to -0.4); P < 0.01; 265 participants; 2 trials; low quality evidence. In most trials the participants with CT needed less insulin, whereas insulin requirements increased or remained stable in participants with IM.We did not perform a meta-analysis for hypoglycaemic events because the included studies used different definitions.. In most trials the insulin-sulphonylurea combination resulted in a higher number of mild episodes of hypoglycaemia, compared to the IM group (range: 2.2 to 6.1 episodes per participant in CT versus 2.0 to 2.6 episodes per participant in IM; low-quality evidence). Pioglitazone CT also resulted in more mild to moderate hypoglycaemic episodes compared with IM (range 15 to 90 episodes versus 9 to 75 episodes, respectively; low-quality evidence. The trials that reported hypoglycaemic episodes in the other combinations found comparable numbers of mild to moderate hypoglycaemic events (low-quality evidence).The addition of sulphonylureas resulted in an additional weight gain of 0.4 kg to 1.9 kg versus -0.8 kg to 2.1 kg in the IM group (220 participants; 7 trials; low-quality evidence). Pioglitazone CT caused more weight gain compared to IM: MD 3.8 kg (95% CI 3.0 to 4.6); P < 0.01; 288 participants; 2 trials; low-quality evidence. Metformin CT was associated with weight loss: MD -2.1 kg (95% CI -3.2 to -1.1), P < 0.01; 615 participants; 7 trials; low-quality evidence). DPP-4 inhibitors CT showed weight gain of -0.7 to 1.3 kg versus 0.6 to 1.1 kg in the IM group (362 participants; 2 trials; low-quality evidence). Alpha-glucosidase CT compared to IM showed a MD of -0.5 kg (95% CI -1.2 to 0.3); P = 0.26; 241 participants; 2 trials; low-quality evidence.Users of metformin CT (range 7% to 67% versus 5% to 16%), and alpha-glucosidase inhibitors CT (14% to 75% versus 4% to 35%) experienced more gastro-intestinal adverse effects compared to participants on IM. Two trials reported a higher frequency of oedema with the use of pioglitazone CT (range: 16% to 18% versus 4% to 7% IM).

AUTHORS' CONCLUSIONS

The addition of all oral glucose-lowering agents in people with type 2 diabetes and inadequate glycaemic control who are on insulin therapy has positive effects on glycaemic control and insulin requirements. The addition of sulphonylureas results in more hypoglycaemic events. Additional weight gain can only be avoided by adding metformin to insulin. Other well-known adverse effects of oral glucose-lowering agents have to be taken into account when prescribing oral glucose-lowering agents in addition to insulin therapy.

Adding glimepiride to insulin+metformin in type 2 diabetes of more than 10 years' duration--a randomised, double-blind, placebo-controlled, cross-over study

AIMS

To investigate the effect on glycaemic control of adding glimepiride to on-going treatment with metformin and insulin in patients with known diabetes more than 10 years.

METHODS

Glimepiride 4 mg or placebo was added in randomised order for three months with a washout period of 6 weeks. All insulin regimens were allowed. Insulin doses were reduced if considered necessary. Continuous glucose monitoring was performed at the end of each period.

RESULTS

Forty-three patients, median age 66 years (46-74), diabetes duration 16 (10-30), BMI 30 kg/m(2) (25-37) and mean HbA1c 7.1% NGSP, (64 mmol/mol IFCC) were randomised. With placebo there was no change in HbA1c while a decrease of 0.6%, (7 mmol/mol IFCC) (P < 0.001), was observed with glimepiride even though insulin doses had to be reduced in 23 patients (median change 29%, range 2-100%). Minor hypoglycaemia was reported but no severe hypoglycaemic event was observed. The ratio between C-peptide/glucose increased significantly (P < 0.001) with glimepiride, both fasting and postprandially and, in a stepwise multiple regression analysis of possible predictive factors for response, a more pronounced decrease in HbA1c was associated with the magnitude of the increment in C-peptide/glucose. Older age was associated with a smaller response. Twenty-nine patients (67%) were defined as responders if this was defined as an HbA1c decrease ≥0.5% (5 mmol/mol IFCC) or an insulin dose reduction ≥20%.

CONCLUSIONS

Even after long duration of diabetes, addition of glimepiride to insulin and metformin can be effective in lowering HbA1c and/or reducing the need for exogenous insulin.

The clinical utility of C-peptide measurement in the care of patients with diabetes

C-peptide is produced in equal amounts to insulin and is the best measure of endogenous insulin secretion in patients with diabetes. Measurement of insulin secretion using C-peptide can be helpful in clinical practice: differences in insulin secretion are fundamental to the different treatment requirements of Type 1 and Type 2 diabetes. This article reviews the use of C-peptide measurement in the clinical management of patients with diabetes, including the interpretation and choice of C-peptide test and its use to assist diabetes classification and choice of treatment. We provide recommendations for where C-peptide should be used, choice of test and interpretation of results. With the rising incidence of Type 2 diabetes in younger patients, the discovery of monogenic diabetes and development of new therapies aimed at preserving insulin secretion, the direct measurement of insulin secretion may be increasingly important. Advances in assays have made C-peptide measurement both more reliable and inexpensive. In addition, recent work has demonstrated that C-peptide is more stable in blood than previously suggested or can be reliably measured on a spot urine sample (urine C-peptide:creatinine ratio), facilitating measurement in routine clinical practice. The key current clinical role of C-peptide is to assist classification and management of insulin-treated patients. Utility is greatest after 3-5 years from diagnosis when persistence of substantial insulin secretion suggests Type 2 or monogenic diabetes. Absent C-peptide at any time confirms absolute insulin requirement and the appropriateness of Type 1 diabetes management strategies regardless of apparent aetiology.