Is combination sulfonylurea and insulin therapy useful in NIDDM patients? A metaanalysis

Rahim AA, Eliana F, Shrestha HK, Chaudhary S, Ngugi N, Mbanya JC, Aye TT, Latt TS, Akanov ZA, Syed AR, Tandon N, Unnikrishnan AG, Madhu SV, Jawa A, Chowdhury S, Bajaj S, Das AK. Consensus Recommendations on Sulfonylurea and Sulfonylurea Combinations in the Management of Type 2 Diabetes Mellitus - International Task Force

For decades, sulfonylureas (SUs) have been important drugs in the antidiabetic therapeutic armamentarium. They have been used as monotherapy as well as combination therapy. Focus on newer drugs and concerns about the risk of severe hypoglycemia and weight gain with some SUs have led to discussion on their safety and utility. It has to be borne in mind that the adverse events associated with SUs should not be ascribed to the whole class, as many modern SUs, such as glimepiride and gliclazide modified release, are associated with better safety profiles. Furthermore, individualization of treatment, using SUs in combination with other drugs, backed with careful monitoring and patient education, ensures maximum benefits with minimal side effects. The current guidelines, developed by experts from Africa, Asia, and the Middle East, promote the safe and smart use of SUs in combination with other glucose-lowering drugs.

Gliclazide

Gliclazide is a second-generation oral hypoglycemic drug used for the treatment of noninsulin-dependent diabetes mellitus. It belongs to the sulfonylurea class that stimulates insulin secretion from pancreatic β-cells by inhibiting ATP-dependent potassium channels. Gliclazide also possesses unique antioxidant properties and other beneficial hemobiological effects. This profile represents a comprehensive description of the physical properties, chemical synthesis, spectroscopic characterization (FTIR, ¹H NMR, ¹³C NMR, UV, and single-crystal X-ray), methods of analysis, pharmacological actions, and pharmacokinetic and pharmacodynamic properties of the title drug.

Pharmacotherapy of 'treatment resistant' type 2 diabetes

INTRODUCTION

Despite type 2 diabetes (T2D) management offers a variety of pharmacological interventions targeting different defects, numerous patients remain with persistent hyperglycaemia responsible for severe complications. Unlike resistant hypertension, treatment resistant T2D is not a classical concept although it is a rather common observation in clinical practice. Areas covered: This article proposes a definition for 'treatment resistant diabetes', analyses the causes of poor glucose control despite standard therapy, briefly considers the alternative approaches to glucose-lowering pharmacotherapy and finally describes how to overcome poor glycaemic control, using innovative oral or injectable combination therapies. Expert opinion: Before considering intensifying the pharmacotherapy of a patient with poorly controlled T2D, it is important to verify treatment adherence, target obesity and consider various non pharmacological improvement quality interventions. If treatment resistant diabetes is defined as not achieving glycated haemoglobin target despite oral triple therapy with a third glucose-lowering agent added to metformin-sulfonylurea dual treatment, the combination of a dipeptidyl peptidase-4 (DPP-4) inhibitor and a sodium glucose cotransporter type 2 (SGLT2) inhibitor may offer new opportunities before considering injectable therapies. Insulin basal therapy (± metformin) may be optimized by the addition of a SGLT2 inhibitor or a glucagon-like peptide-1 (GLP-1) receptor agonist.

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.

Comparative Effectiveness of Insulin versus Combination Sulfonylurea and Insulin: a Cohort Study of Veterans with Type 2 Diabetes

BACKGROUND

Type 2 diabetes patients often initiate treatment with a sulfonylurea and subsequently intensify their therapy with insulin. However, information on optimal treatment regimens for these patients is limited.

OBJECTIVE

To compare risk of cardiovascular disease (CVD) and hypoglycemia between sulfonylurea initiators who switch to or add insulin.

DESIGN

This was a retrospective cohort assembled using national Veterans Health Administration (VHA), Medicare, and National Death Index databases.

PARTICIPANTS

Veterans who initiated diabetes treatment with a sulfonylurea between 2001 and 2008 and intensified their regimen with insulin were followed through 2011.

MAIN MEASURES

The association between insulin versus sulfonylurea + insulin and time to CVD or hypoglycemia were evaluated using Cox proportional hazard models in a 1:1 propensity score-matched cohort. CVD included hospitalization for acute myocardial infarction or stroke, or cardiovascular mortality. Hypoglycemia included hospitalizations or emergency visits for hypoglycemia, or outpatient blood glucose measurements <60 mg/dL. Subgroups included age < 65 and ≥ 65 years and estimated glomerular filtration rate ≥ 60 and < 60 ml/min.

KEY FINDINGS

There were 1646 and 3728 sulfonylurea monotherapy initiators who switched to insulin monotherapy or added insulin, respectively. The 1596 propensity score-matched patients in each group had similar baseline characteristics at insulin initiation. The rate of CVD per 1000 person-years among insulin versus sulfonylurea + insulin users were 49.3 and 56.0, respectively [hazard ratio (HR) 0.85, 95 % confidence interval (CI) 0.64, 1.12]. Rates of first and recurrent hypoglycemia events per 1000 person-years were 74.0 and 100.0 among insulin users compared to 78.9 and 116.8 among sulfonylurea plus insulin users, yielding HR (95 % CI) of 0.94 (0.76, 1.16) and 0.87 (0.69, 1.10), respectively. Subgroup analysis results were consistent with the main findings.

CONCLUSIONS

Compared to sulfonylurea users who added insulin, those who switched to insulin alone had numerically lower CVD and hypoglycemia events, but these differences in risk were not statistically significant.

Withdrawal of sulfonylureas from patients with type 2 diabetes receiving long-term sulfonylurea and insulin combination therapy results in deterioration of glycemic control: a randomized controlled trial

BACKGROUND

The benefit of sulfonylureas (SUs) to patients with type 2 diabetes mellitus receiving long-term insulin treatment is unclear. This study evaluated glycemic control and beta-cell function after SU withdrawal in these patients.

METHODS

In this 8-week randomized controlled study, patients with type 2 diabetes who had been treated with insulin for at least 3 years plus moderate to high doses of SUs were randomly assigned to withdrawal (n=16) or continuation (n=16) of SUs. Clinical characteristics, glycemic control, hypoglycemic events, and insulin secretion, including homeostasis model assessment of beta-cell function (HOMA-B) score, C-peptide concentration, and Matsuda index, were evaluated at baseline and after 2 and 8 weeks.

RESULTS

Thirty patients (16 in the SU withdrawal group and 14 in the SU continuation group) completed the study. Median duration of diabetes was 17 (range 5-40) years. Baseline clinical characteristics, glycemic control, and HOMA-B were similar in the two groups, but the mean fasting C-peptide concentration was higher in the SU withdrawal group. After 8 weeks, the SU withdrawal group showed a significant increase in mean glycosylated hemoglobin levels from 7.8%±0.5% (62±5 mmol/mol) to 8.6%±1.2% (71±13 mmol/mol; P=0.002), whereas the SU continuation group showed a slight but not significant increase from 7.7%±0.5% (61±5 mmol/mol) to 7.9%±1.2% (63±13 mmol/mol; P=0.37). Insulin secretion, as measured by C-peptide and HOMA-B, decreased by 18% and 36%, respectively, in the SU withdrawal group. Hypoglycemic events were significantly more frequent in the SU continuation group whereas body weight did not change significantly in either group.

CONCLUSION

Withdrawal of SU from patients with type 2 diabetes receiving long-term combination treatment with SU and insulin resulted in deterioration of glycemic control and insulin secretion.

Sulfonylurea in combination with insulin is associated with increased mortality compared with a combination of insulin and metformin in a retrospective Danish nationwide study

AIMS/HYPOTHESIS

Individual sulfonylureas (SUs) and metformin have, in some studies, been associated with unequal hypoglycaemic, cardiovascular and mortality risks when used as monotherapy in type 2 diabetes. We investigated the outcomes in patients treated with different combinations of SUs and insulin vs a combination of metformin and insulin in a retrospective nationwide study.

METHODS

All Danish individuals using dual therapy with SU + insulin or metformin + insulin without prior myocardial infarction (MI) or stroke were followed from 1 January 1997 to 31 December 2009 in nationwide registries. Risks of all-cause mortality, cardiovascular death, hypoglycaemia and a composite endpoint of MI, stroke and cardiovascular death were compared. Rate ratios (RR) [95% CIs] were calculated using time-dependent multivariable Poisson regression analysis.

RESULTS

A total of 11,081 patients used SU + insulin and 16,910 used metformin + insulin. Patients receiving metformin + insulin were younger and had less comorbidity and a longer history of glucose-lowering treatment. SU + insulin was associated with higher mortality rates compared with metformin + insulin (76-126 vs 23 per 1,000 person-years). In adjusted analyses, SU + insulin was associated with increased all-cause mortality (RR 1.81 [1.63, 2.01]), cardiovascular death (RR 1.35 [1.14, 1.60]) and the composite endpoint (RR 1.25 [1.09, 1.42]) compared with metformin + insulin. Hypoglycaemia was more frequent with SU + insulin than with metformin + insulin (17-23 vs six events per 1,000 person-years) and was associated with increased mortality (RR 2.13 [1.97, 2.37]). There were no significant differences in risk between individual SUs in combination with insulin.

CONCLUSIONS/INTERPRETATION

In combination with insulin, the use of SUs was associated with increased mortality compared with metformin. There were no significant risk differences between SUs.

Estimating the effect of sulfonylurea on HbA1c in diabetes: a systematic review and meta-analysis

AIMS/HYPOTHESIS

Sulfonylureas are widely prescribed glucose-lowering medications for diabetes, but the extent to which they improve glycaemia is poorly documented. This systematic review evaluates how sulfonylurea treatment affects glycaemic control.

METHODS

Medline, EMBASE, the Cochrane Library and clinical trials registries were searched to identify double-blinded randomised controlled trials of fixed-dose sulfonylurea monotherapy or sulfonylurea added on to other glucose-lowering treatments. The primary outcome assessed was change in HbA1c, and secondary outcomes were adverse events, insulin dose and change in body weight.

RESULTS

Thirty-one trials with a median duration of 16 weeks were included in the meta-analysis. Sulfonylurea monotherapy (nine trials) lowered HbA1c by 1.51% (17 mmol/mol) more than placebo (95% CI, 1.25, 1.78). Sulfonylureas added to oral diabetes treatment (four trials) lowered HbA1c by 1.62% (18 mmol/mol; 95% CI 1.0, 2.24) compared with the other treatment, and sulfonylurea added to insulin (17 trials) lowered HbA1c by 0.46% (6 mmol/mol; 95% CI 0.24, 0.69) and lowered insulin dose. Higher sulfonylurea doses did not reduce HbA1c more than lower doses. Sulfonylurea treatment resulted in more hypoglycaemic events (RR 2.41, 95% CI 1.41, 4.10) but did not significantly affect the number of other adverse events. Trial length, sulfonylurea type and duration of diabetes contributed to heterogeneity.

CONCLUSIONS/INTERPRETATION

Sulfonylurea monotherapy lowered HbA1c level more than previously reported, and we found no evidence that increasing sulfonylurea doses resulted in lower HbA1c. HbA1c is a surrogate endpoint, and we were unable to examine long-term endpoints in these predominately short-term trials, but sulfonylureas appear to be associated with an increased risk of hypoglycaemic events.

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

AIM

To investigate the efficacy of continuing glimepiride in combination with basal-prandial insulin therapy in type 2 diabetes.

METHODS

An open crossover study was performed with arms of discontinuation and continuation of glimepiride in 25 subjects with mean diabetes duration of 17 years and 5 years of insulin treatment combined with glimepiride plus metformin. At entry and at the end of each 3-month arm, meal tolerance tests were performed for measurements of blood glucose and C-peptide.

RESULTS

In terms of between-treatment differences (discontinuation vs. continuation arm of glimepiride) during meal tolerance tests performed at the ends of arms, significant increases in plasma glucose were seen on the discontinuation arm at 0-, 30-, and 60-min, while significant decreases in serum C-peptide were observed at 60- and 120-min. A1C values of the discontinuation arm significantly increased (from 6.6 ± 0.6 at baseline to 7.7 ± 0.8 at 3-months, p<0.0001). Increases in A1C were closely correlated with decreases in area under the curve of meal-stimulated serum C-peptide (r=-0.61, p<0.0001).

CONCLUSIONS

Since endogenous insulin secretion is more physiological than subcutaneous insulin injection, continuing glimepiride may remain beneficial, partly through enhancing insulin secretion, in individuals with a long duration of diabetes and basal-prandial insulin therapy.

[Types of insulin therapy]

Diabetes mellitus is a chronic disease associated with a series of long-term microvascular and macrovascular complications that requires continuing therapeutic control. In recent years, the pharmaceutical industry has developed new types of insulin and administration systems in order to more closely mimic human insulin secretion. In this way, insulin therapy is divided into conventional and intensive regimens according to their complexity. In type 1 diabetes mellitus (T1DM) patients, the treatment of choice is the one which achieves intensive glycemic control. In type 2 diabetes mellitus, we can start with a simplified conventional regimen which could progress into an intensive one similar to that of T1DM treatment. Both types of diabetes require an individualized treatment prescription based on the needs and characteristics of each patient.

Why insulin sensitizers but not secretagogues should be retained when initiating insulin in type 2 diabetes

The stringent targets set for HbA(1c) levels in type 2 diabetes are currently achieved by fewer than half the patients in the United States. Failure to manage hyperglycaemia in the early stages of disease results in progressive loss of beta-cell function, which ultimately necessitates the initiation of insulin therapy. At this point, choices have to be made on whether to continue oral anti-diabetic drug therapy and, if so, with which agent(s). Historically, sulfonylureas have been the mainstay of oral anti-diabetic drug therapy; however, their long-term efficacy in patients with depleted beta-cell capacity is doubtful, and other classes of oral anti-diabetic drugs, notably the insulin sensitizers, may prove more reliable. These agents (metformin and thiazolidinediones) appear to provide various benefits over and above sustained glycaemic control, which may variably include reduced loss of beta-cell function as well as improvements to cardiovascular risk factors, morbidity, and mortality. Metformin also limits weight gain associated with insulin therapy. This manuscript presents the case that when insulin therapy is initiated it should be tailored to individual needs through combination with one or more insulin sensitizers rather than a secretagogue.

Glycaemic responsiveness to long-term insulin plus sulphonylurea therapy as assessed by sulphonylurea withdrawal

AIMS

To assess the effect of sulphonylurea (SU) in patients with Type 2 diabetes undergoing long-term combination therapy with insulin, by withdrawal of SU, and to identify clinically useful markers of long-term response.

METHODS

We studied 25 patients, aged 59-83 years, mean glycated haemoglobin (HbA(1c)) 7.0 +/- 0.6%, who had been treated with SU for 16 years (7-24 years) in combination with insulin for 10 years (6-15 years). After basal measurements, SU was withdrawn. Fasting plasma glucose (FPG) and C-peptide were then monitored every 2-3 days during the following 2 weeks. If FPG increased > 40% or P-glucose exceeded 20 mmol/l, SU was restarted. If neither criterion was met, a clinical follow-up visit with measurement of HbA(1c) was scheduled within 8 weeks.

RESULTS

Twenty patients were restarted on SU because of worsening glycaemic control, eight within the first 4 weeks and the remaining 12 at the follow-up visit as their HbA(1c) had increased by 1.1% (range 0.4-2.0%). All these patients were defined as 'SU responders'. The increase in FPG during the initial 2 weeks correlated positively with duration of diabetes (P < 0.01) and duration of SU treatment (P < 0.001). The 'SU responders' had higher levels of basal fasting C-peptide (0.84 +/- 0.44 vs. 0.41 +/- 0.15 nmol/l, P < 0.05), but the variation was wide and none of the measured variables identified 'SU responders'.

CONCLUSIONS

In 80% of this group of patients, glycaemic control deteriorated after SU withdrawal despite long duration of SU treatment.

Rosiglitazone versus bedtime insulin in the treatment of patients with conventional oral antidiabetic drug failure: a 1-year randomized clinical trial

This study was conducted to evaluate the efficacy and tolerability of rosiglitazone in the treatment of patients with secondary oral antidiabetic drug (OAD) failure and to directly compare its use with bedtime insulin. A total of 112 Chinese patients with type 2 diabetes and conventional OAD failure were recruited. Patients were randomly assigned to treatment with rosiglitazone or bedtime isophane insulin; they continued to take their original oral antidiabetic drugs. Glycemic index, other clinical profiles, and tolerability were assessed during treatment and 1 y after add-on treatment was provided. Among the 112 patients, mean age (+/-SD) was 58.2+/-11.0 y (median, 58 y; range, 37 to 84 y). Both rosiglitazone (n=56) and insulin (n=56) significantly improved fasting glucose (2.4 and 3.7 mmol/L, respectively) and hemoglobin A1c concentrations (1.1% and 1.3%, respectively). Both therapies increased body mass index after 1 y of treatment (0.9 and 0.8 kg/m2, respectively). Only rosiglitazone increased high-density lipoprotein cholesterol concentrations (0.1 mmol/L). Four patients (7.1%) who were given rosiglitazone developed adverse effects (2, ankle edema, and 2, gastrointestinal disturbance). Six insulin-treated patients (10.7%) described adverse effects (5, early morning hypoglycemia, and 1, anxiety). Investigators concluded that in Chinese patients with type 2 diabetes and secondary conventional OAD failure, 1 y of treatment with rosiglitazone or bedtime insulin added to the regular regimen resulted in similar improvements in glycemic control. Rosiglitazone was also associated with improved high-density lipoprotein cholesterol levels. The addition of rosiglitazone may offer a safe and effective alternative to bedtime insulin treatment.

Is it time to re-assess the role of gliclazide? Targeting insulin resistance in type 2 diabetes patients suboptimally controlled with insulin

BACKGROUND

Adult patients with type 2 diabetes controlled with insulin frequently require the addition of insulin sensitising drugs such as metformin and sometimes glitazones to achieve optimum glycaemic control. Five of a group of eight people with suboptimal diabetes control who were treated by the introduction of gliclazide are reported on. Three patients were excluded. One with type 1 diabetes and two others who had dietary or other therapeutic interventions coinciding with re-introduction gliclazide. Does the re-introduction of gliclazide effect a clinically significant improvement in glycaemic control in type 2 diabetes patients with suboptimal control taking combinations of short and long acting insulin plus metformin?

METHOD

Five adult patients with type 2 diabetes with suboptimal control using combinations of short and long acting insulin plus metformin who were adherent to their dietary regimen were treated by the addition of gliclazide at different doses. Two of the patients were taking pioglitazone in addition to metformin and insulin. Their glycaemic control was monitored over the following six months.

RESULTS

All five showed significant improvement in glycaemic control after three months. Mean reduction in HbA1c was 1.4% (range 0.9% to 2.5%). Six months after the introduction of gliclazide four patients had HbA1c below base line figure and in two patients clinically significant improvement had been maintained.

CONCLUSION

A double blind randomised placebo control study is necessary to evaluate a possible role for gliclazide in type 2 diabetes patients who have suboptimal glycaemic control using combinations of short and long acting insulin plus metformin.

Insulin glargine or NPH combined with metformin in type 2 diabetes: the LANMET study

AIMS/HYPOTHESIS

In type 2 diabetic patients we compared 9 months of combination therapy with insulin glargine and metformin with 9 months of NPH insulin combined with metformin. The primary focus was changes in HbA(1c); secondary focus was diurnal glucose profiles and symptomatic hypoglycaemia.

METHODS

In this investigator-initiated open, parallel-group clinical trial involving seven centres, 110 insulin-naive type 2 diabetic patients with poor glycaemic control (HbA(1c) >or=8.0%) on oral hypoglycaemic agents (90% using sulfonylurea plus metformin) were randomised to receive bedtime insulin glargine with metformin (G+MET) or bedtime NPH with metformin (NPH+MET) for 36 weeks. The patients were taught how to self-adjust their insulin dose and use a modem to send the results of home glucose monitoring to treatment centres. The goal was to achieve a fasting plasma glucose (FPG) of 4.0 to 5.5 mmol/l in both groups.

RESULTS

During the last 12 weeks, FPGs averaged 5.75+/-0.02 and 5.96+/-0.03 mmol/l (p<0.001) and insulin doses were 68+/-5 and 70+/-6 IU/day (0.69+/-0.05 and 0.66+/-0.04 IU kg(-1) day(-1), NS) in the G+MET and NPH+MET groups, respectively. At 36 weeks, mean HbA(1c) was 7.14+/-0.12 and 7.16+/-0.14%, respectively (NS). Symptomatic, but not confirmed symptomatic, hypoglycaemia was significantly lower during the first 12 weeks in the G+MET group (4.1+/-0.8 episodes/patient-year) than in the NPH+MET group (9.0+/-2.3 episodes/patient-year, p<0.05), but not significantly different thereafter. Glucose levels before dinner were higher in the NPH+MET group (10.1+/-0.3 mmol/l) than in the G+MET group (8.6+/-0.3 mmol/l, p=0.002) throughout the 36-week study. With regard to baseline characteristics such as initial glycaemia or C-peptide, there was no difference between patients who achieved good glycaemic control (HbA(1c) <7.0%) and those who did not. Differences were seen in the following: between study centres, weight gain during the run-in period and insulin therapy, and FPG during the last 12 weeks (5.7+/-0.2 vs 6.7+/-0.3 mmol/l for patients reaching vs those not reaching target, p<0.01).

CONCLUSIONS/INTERPRETATION

Good glycaemic control can be achieved with both G+MET and NPH+MET. Use of G+MET reduces symptomatic hypoglycaemia during the first 12 weeks and dinner time hyperglycaemia compared with NPH+MET.

Making the transition from oral to insulin therapy

The typically long delay in starting insulin for patients with type 2 diabetes mellitus may be due in part to uncertainty about how best to make the transition from oral therapy to insulin. Recent studies show that when appropriate glycemic targets are sought, with systematic titration of insulin dosage, several methods of beginning insulin may be successful. Notably, either starting with a single injection of basal insulin or starting with 3 injections of short-acting insulin at mealtimes can be effective. Studies also suggest that continuing oral therapies and using insulin analogues rather than human insulins may improve the effectiveness of insulin treatment relative to the rate of hypoglycemia and gain of weight typically seen in this setting. Starting with a single injection of insulin to control basal glycemia while continuing oral therapy is the simplest approach, and lends itself to stepwise addition of mealtime injections as needed to bring most patients to glycemic targets in a logical and practical way. Future studies should consider not only the ability of regimens to reach hemoglobin A(1c) targets but also the burden of adverse effects accompanying this effort with a given method.

Effect of adding a sulfonylurea in patients with non-insulin-dependent diabetes mellitus previously well controlled with insulin

OBJECTIVE

To determine whether insulin-requiring patients with non-insulin-dependent diabetes mellitus (NIDDM) and good glycemic control would benefit in weight control, serum lipid concentrations, or blood pressure from a reduction in exogenous insulin treatment.

METHODS

Eighteen patients with well-controlled NIDDM who required insulin therapy were entered into a randomized, placebo-controlled, double-blind, crossover study of the addition for 12 weeks of treatment with a second-generation sulfonylurea agent (micronized glyburide).

RESULTS

The mean fasting plasma glucose at entry was 7.00 +/- 0.22 mmol/L and at the end of the 12-week treatment phase was 7.67 +/- 0.39 mmol/L with placebo and 7.28 +/- 0.44 mmol/L with active drug. Hemoglobin A(1c) was unchanged during the study (7.5 +/- 0.2% at entry, 7.5 +/- 0.3% with placebo, and 7.4 +/- 0.3% with active drug). Addition of the orally administered agent resulted in a 29% decrease in exogenous insulin requirements and a 37% increase in 24-hour urinary C-peptide excretion. Patients had no change in weight after 12 weeks of either placebo or active drug. Plasma cholesterol levels declined slightly during the study, but they did not differ significantly during drug and placebo treatment. Blood pressure was unchanged in both the subjects with and without hypertension.

CONCLUSION

In patients with NIDDM and good glycemic control with insulin treatment, a glyburide-related increase in endogenous insulin secretion caused a proportionate decrease in exogenous insulin requirements. With continued good glycemic control, however, the orally administered agent showed no additional benefit on weight, blood pressure, plasma triglycerides, or low-density lipoprotein or high-density lipoprotein cholesterol.

Insulin monotherapy versus combinations of insulin with oral hypoglycaemic agents in patients with type 2 diabetes mellitus

BACKGROUND

It is unclear whether patients with type 2 diabetes who have poor glycaemic control despite maximal oral hypoglycaemic agents (OHAs) should be commenced on insulin as monotherapy, or insulin combined with oral hypoglycaemic agents (insulin-OHA combination therapy).

OBJECTIVES

To assess the effects of insulin monotherapy versus insulin-OHA combinations therapy.

SEARCH STRATEGY

Eligible studies were identified by searching MEDLINE, EMBASE, and The Cochrane Library. Date of last search: May 2004.

SELECTION CRITERIA

Randomised controlled trials (RCTs) with 2 months minimum follow-up duration comparing insulin monotherapy (all schemes) with insulin-OHA combination therapy.

DATA COLLECTION AND ANALYSIS

Data extraction and assessment of study quality were undertaken by three reviewers in pairs.

MAIN RESULTS

Twenty RCTs (mean trial duration 10 months) including 1,811 participants, with mean age 59.8 years and mean known duration of diabetes 9.6 years. Overall, study methodological quality was low. Twenty-eight comparisons in 20 RCTs were ordered according to clinical considerations. No studies assessed diabetes-related morbidity, mortality or total mortality. From 13 studies (21 comparisons), sufficient data were extracted to calculate pooled effects on glycaemic control. Insulin-OHA combination therapy had statistically significant benefits on glycaemic control over insulin monotherapy only when the latter was applied as a once-daily injection of NPH insulin. Conversely, twice-daily insulin monotherapy (NPH or mixed insulin) provided superior glycaemic control to insulin-OHA combination therapy regimens where insulin was administered as a single morning injection. In more conventional comparisons, regimens utilising OHAs with bedtime NPH insulin provided comparable glycaemic control to insulin monotherapy (administered as twice daily, or multiple daily injections). Overall, insulin-OHA combination therapy was associated with a 43% relative reduction in total daily insulin requirement compared to insulin monotherapy. Of the 14 studies (22 comparisons) reporting hypoglycaemia, 13 demonstrated no significant difference in the frequency of symptomatic or biochemical hypoglycaemia between insulin and combination therapy regimens. No significant differences in quality of life related issues were detected. Combination therapy with bedtime NPH insulin resulted in statistically significantly less weight gain compared to insulin monotherapy, provided metformin was used +/-sulphonylurea. In all other comparisons no significant differences with respect to weight gain were detected.

REVIEWERS' CONCLUSIONS

Bedtime NPH insulin combined with oral hypoglycaemic agents provides comparable glycaemic control to insulin monotherapy and is associated with less weight gain if metformin is used.

Insulin therapy in type 2 diabetes

Unlike type 1 diabetic patients, who have no significant insulin secretion and require insulin therapy from the disease onset, a prominent feature in the early stages of type 2 diabetes is insulin resistance with hyperinsulinemia. Therefore, improving insulin sensitivity by diet, exercise, and weight management will benefit type 2 diabetic patients. When these measures fail, glycemic goals may be achieved with oral agents. However, at the late stage of disease,most patients require exogenous insulin therapy to achieve optimal glucose control. The American Diabetes Association recommends that the objective of normalizing glycemia and glycosylated hemoglobin concentrations for patients with type 2 diabetes should be similar to that for type 1 diabetes.

Insulin therapy in type 2 diabetes: role of the long-acting insulin glargine analogue

Insulin glargine is a long-acting insulin analogue, with a longer duration of action and a flatter time-action profile compared with NPH insulin. These properties can be predicted to result in higher glucose levels during the night and lower glucose levels after dinner following bedtime injection of insulin glargine compared with an equal dose of NPH insulin injected at bedtime. In two large-scale clinical trials involving either insulin-naïve (426 patients treated for 1 year) or previously insulin-treated (518 patients treated for 28 weeks) patients with type 2 diabetes, comparing addition of once-daily insulin glargine or NPH insulin to oral agents, these predictions were proven to be correct. Nocturnal hypoglycaemia was reduced by 58% in insulin-naive patients and by 22% in previously insulin-treated patients, and dinner-time glucose control was significantly better with insulin glargine than with NPH insulin once daily in the study in insulin-naive patients. The 'treat-to-target study' (756 insulin-naive patients treated for 24 weeks) showed that good glycaemic control can be achieved with aggressive titration of the insulin dose with either once-daily insulin glargine or NPH insulin combined with oral agents (mean endpoint HbA(1c) was 6.96% with insulin glargine and 6.97% with NPH insulin); however, this was achieved with less variability and nocturnal hypoglycaemia with insulin glargine. These data support use of insulin glargine instead of NPH insulin for basal insulin replacement in patients with type 2 diabetes.

A review of basal insulins

Tight glycaemic control (ideally, HbA1c<7%) is central to reducing the risk of long-term complications of diabetes. This approach, for both Type 1 and Type 2 diabetes, commonly involves the use of basal insulin, and must be achieved with minimal risk of hypoglycaemia (particularly nocturnal episodes). Indeed, concern around hypoglycaemia is a major barrier to achieving tight glycaemic control, and is a common problem with those protracted-acting insulins most frequently used in clinical practice for basal insulin supply. Other drawbacks include inter- and intra-patient variability that compromises dosing reproducibility and unsuitability for single daily dosing. New long-acting human insulin analogues with action profiles designed to overcome these problems are now available in clinical practice or are under evaluation in clinical trials. Clinical evidence suggests efficacy and safety advantages for these analogues over NPH insulin (the most commonly used basal insulin), and may bring closer the goal of tight glycaemic control in patients with diabetes.

Combined bedtime insulin--daytime sulphonylurea regimen compared with two different daily insulin regimens in type 2 diabetes: effects on HbA1c and hypoglycaemia rate--a randomised trial

BACKGROUND

Several efficacy studies of insulin-therapy regimens in patients with type 2 diabetes mellitus have shown varying results. Moreover, most studies did not address hypoglycaemia frequency and severity.

METHODS

In this multicentre study, we compared the glycaemic efficacy and incidence rate of hypoglycaemic episodes between 3 treatment regimens in obese type 2 diabetic patients with secondary failure to sulphonylurea and metformin. During the run-in phase, patients were treated with glimepiride and metformin. After 3 months, 261 patients with HbA(1c) values >6.5% were randomised to (A) glimepiride + Neutral Protein Hagedorn (NPH) insulin at bedtime, (B) NPH insulin twice daily and (C) 30/70 mixture of short-acting and NPH insulin twice daily. The therapeutic aim was an HbA(1c) level < or =6.5%.

RESULTS

Mean HbA(1c) achieved at 9 months was significantly higher in group A: 8.9% versus 8.3% and 8.4% in groups B and C, respectively (P < 0.001). There was no difference in the mild hypoglycaemic event rate, 0.36 versus 0.48 versus 0.53 events per patient month, in groups A, B and C, respectively. Severe hypoglycaemic events, requiring help from others, did not occur throughout the study. The mean weight gain and insulin dose were comparable in all three groups.

CONCLUSIONS

The glimepiride + NPH insulin treatment resulted in a higher HbA(1c) level, as compared to the other regimens. In the clinical setting of this multicentre study, good glycaemic control was only achieved in a minority of the patients, irrespective of the applied regimen.

The contribution of metformin to glycaemic control in patients with Type 2 diabetes mellitus receiving combination therapy with insulin

Combination therapy of oral hypoglycaemic agents and insulin is a therapeutic option for those who have deterioration in glycaemic control. We examined the contribution of metformin by withdrawing it from Type 2 diabetic patients who had been stabilised on combination therapy. Fifty-one subjects with Type 2 diabetes and secondary oral hypoglycaemic agent failure were studied in a randomised, open and parallel study. In the first phase of 36 weeks, subjects were stabilised on combined therapy of sulphonylureas and nocturnal insulin, with or without metformin. During the second phase, metformin was withdrawn. The primary variables for efficacy were HbA(1c), fasting plasma glucose and 3-point capillary blood glucose profiles. After stabilisation with combination therapy, those subjects on metformin used less insulin to maintain glycaemic control (13.7+/-6.8 vs. 23.0+/-9.4 U/day, P=0.001) and had lower HbA(1c) values (8.13+/-0.89 vs. 9.05+/-1.30%, P=0.003) compared with those not given metformin. Withdrawal of metformin therapy caused deterioration in HbA(1c) (P=0.001). This study confirms that metformin plays an important role in the success of the combination therapy. The rational use of metformin and sulphonylurea together with insulin will help to improve metabolic control in Type 2 diabetes patients who have secondary drug failure.

Comparative assessment of the treatment of type 2 diabetes mellitus

BACKGROUND

The objective of the study was to estimate the most successful way of treating patients with type 2 diabetes mellitus.

PATIENTS AND METHODS

A total of 87 patients with type 2 diabetes mellitus were selected for a three-month study. The patients were divided into three groups comprising 29 patients in each group, based upon the treatment regimen. Group 1 (BMI 32.3+/-3.6 kg/m(2)) was treated with glimepiride and metformin; group 2 (BMI 27.9+/-3.9) was treated with daily doses of insulin mixture 30/70 and bed-time NPH insulin; and group 3 (BMI 30.2+/-4.8) was treated with a combination of three daily doses of lispro and metformin. The groups did not differ significantly in terms of sex and age.

RESULTS

Initially, there were significant statistical differences in HbA1c (P=0.035) between the three groups (9.21%+/-1.72%; 9.21%+/-1.54%; and 10,0%+/-1.73%, respectively). After three months, there were no statistically significant differences in HbA1c (P=0.66) between the groups (8.52%+/-1.7%; 8.03%+/-1.05%; and 8.0%+/-0.63%, respectively). Decreases in HbA(1c) were significant in all groups, but most pronounced in patients treated with lispro and metformin (17% on average).

CONCLUSION

The study results suggest the need for establishing guidelines on how to treat type 2 diabetics.

Combination oral agent and insulin therapy for type 2 diabetes mellitus

Type 2 diabetes is a chronic metabolic disorder that results from defects in both insulin secretion and insulin action. Over time, there is progressive beta-cell failure. Combination oral and insulin therapy aims at treating both the defects in underlying pathophysiology and replacing insulin once beta-cell failure has occurred. Combination therapy is routinely used in the management of diabetes to reduce hemoglobin A1c, weight gain, and the number of insulin injections a patient requires. This article examines the effects of combining various oral agents with insulin on glycemic control, hypoglycemia, weight gain, and nonglycemic benefits of these combinations.

[Role and modalities of insulin treatment in type 2 diabetics]

INTRODUCTION

The natural history of type 2 diabetes mellitus is characterized by an inescapable and gradual worsening of a decrease in insulin secretion. Thus after several years of progress, less than half of type 2 diabetic patients have good glycemic control. This explains the increase in insulin prescription to type 2 diabetic patients in France in recent years. This work's objective is to take into account recent publication data to clarify the status of and adjustments in insulin therapy.

CURRENT KNOWLEDGE AND KEY POINTS

The benefit of insulin treatment-mediated glycemic control optimization on microvascular complications is now proven. However, there is still controversy concerning macrovascular complications. Hypoglycemic risk in type 2 diabetic patients is limited and the main problem with insulin treatment is weight gain. Following failure with treatment by tablets, the most suitable treatment in terms of metabolic improvement, weight gain limitation and treatment adhesion is to add an intermediate insulin injection at bedtime. The next step remains several injections a day, with metformine addition if possible.

FUTURE PROSPECTS AND PROJECTS

Therapeutic treatment in type 2 diabetes mellitus may become an earlier start of insulin therapy to preserve the remaining pancreatic insulin reserve. The role of brief and long-lasting insulin analogues, as well as inhaled insulin, which will soon be available, should be specified.

Non insulin-dependent diabetes mellitus (type 2) secondary failure. Metformin-glibenclamide treatment

The goal of sulphonylurea (S) treatment in Non-Insulin-Dependent Diabetes Mellitus (NIDDM - type 2 diabetes) subjects should be to obtain a satisfactory glycemic control (fasting glycemic levels &#x003C; 140 mg&#x0025;). The loss of an adequate blood glucose control after an initial variable period of S is known as secondary failure (SF). The number of SF are extremely variable among different trials for many reasons, some of which are patient-related: increased food intake, weight gain, non-compliance, poor physical activity, stress, diseases and&#x00F7;or impaired pancreatic beta cell function, desensitization after S chronic therapy, reduced absorption, concomitant therapies. Many therapeutic strategies have been proposed to achieve an adequate metabolic control in type 2 diabetes patients: switch to intensive insulin therapy and subsequent return to S therapy; association with insulin; association with sulphonylureas plus biguanides. The association biguanides and S, in particular glibenclamide plus metformin, is now widely used by diabetologists in SF since glibenclamide improves insulin secretion while metformin exerts its antidiabetic.

Gliclazide and bedtime insulin are more efficient than insulin alone for type 2 diabetic patients with sulfonylurea secondary failure

To determine the effects of combined therapy of gliclazide and bedtime insulin on glycemic control and C-peptide secretion, we studied 25 patients with type 2 diabetes and sulfonylurea secondary failure, aged 56.8 +/- 8.3 years, with a duration of diabetes of 10.6 +/- 6.6 years, fasting plasma glucose of 277.3 +/- 64.6 mg/dl and a body mass index of 27.4 +/- 4.8 kg/m2. Patients were submitted to three therapeutic regimens lasting 2 months each: 320 mg gliclazide (phase 1), 320 mg gliclazide and bedtime NPH insulin (phase 2), and insulin (phase 3). At the end of each period, glycemic and C-peptide curves in response to a mixed meal were determined. During combined therapy, there was a decrease in all glycemic curve values (P<0.01). Twelve patients (48%) reached fasting plasma glucose <140 mg/dl with a significant weight gain of 64.8 kg (43.1-98.8) vs 66.7 kg (42.8-101.4) (P<0.05), with no increase in C-peptide secretion or decrease in HbA1. C-Peptide glucose score (C-peptide/glucose x 100) increased from 0.9 (0.2-2.1) to 1.3 (0.2-4.7) during combined therapy (P<0.01). Despite a 50% increase in insulin doses in phase 3 (12 U (9-30) vs 18 U (11-60); P<0.01) only 3 patients who responded to combined therapy maintained fasting plasma glucose <140 mg/dl (P<0.02). A tendency to a higher absolute increase in C-peptide (0.99 (0.15-2.5) vs 0.6 (0-2.15); P = 0.08) and C-peptide incremental area (2.47 (0.22-6.2) vs 1.2 (0-3.35); P = 0.07) was observed among responders. We conclude that combined therapy resulted in a better glucose response to a mixed meal than insulin alone and should be tried in type 2 diabetic patients before starting insulin monotherapy, despite difficulties in predicting the response.

Optimising therapy for insulin-treated type 2 diabetes mellitus

The purpose of this article is to provide a guide to the optimal use of insulin in type 2 (non-insulin-dependent) diabetes mellitus. Based on pathophysiological considerations and a knowledge of drug actions, an individualised, targeted strategy is selected for obtaining good metabolic control without compromising well-being and quality of life. The treatment should target hyperglycaemia along with other risk factors. Insulin is indicated when adequate glycaemia can no longer be obtained with diet and oral antihyperglycaemic agents. Commonly, the oral drugs are replaced by insulin, but preferably they should be used in combination with insulin. This approach can lead to improved glycaemic control, a reduced insulin dose and counteraction of insulin-associated bodyweight gain. There may also be less hypoglycaemia with combination insulin/oral therapy as compared with insulin monotherapy, as well as other benefits. Optimisation of oral drug therapy should be attempted before initiating insulin. A combination of insulin with a sulphonylurea agent is commonly used: the adjunctive effect of the sulphonylurea is dependent on pancreatic beta cell function. The combination of insulin with metformin or a thiazolidinedione is more logical as insulin resistance is targeted directly. Bedtime insulin plus metformin conferred the most benefits among several options investigated in a randomised 1-year study. The combination of insulin with acarbose is a further option when there is significant postprandial hyperglycaemia. It is recommended to start with a medium- to long-acting insulin preparation at bedtime or premixed insulin before the evening meal. Changes in insulin administration can be subsequently introduced as needed, e.g. use of twice-daily premixed insulin, multiple injections of rapid-acting insulin or insulin analogues. There are many options, but limited clinical data are available to support a number of the regimens.

Pharmacotherapy of type 2 diabetes mellitus

OBJECTIVE

To review the drug treatments and some of the popular, nontraditional remedies now available for type 2 diabetes mellitus, as well as selected investigational agents; to describe each medication's place in the overall approach to treatment.

DATA SOURCES

English-language journals, abstracts, review articles, and newspaper accounts.

DATA SYNTHESIS

In the past five years, there has been tremendous progress in the pharmacotherapy of diabetes, particularly type 2 diabetes. Several new agents have entered the clinical arena, and many more are in the late stages of investigation leading to approval. Sulfonylureas stimulate the production and release of insulin; these drugs must be used in patients with an intact pancreas. The meglitinides are nonsulfonylurea agents that are also insulin secretagogues. Unlike the sulfonylureas, repaglinide appears to require the presence of glucose to close the adenosine triphosphate-sensitive potassium channels and induce calcium influx. Metformin reduces hepatic glucose production in some patients and increases peripheral glucose utilization, but its use is hampered by a high percentage of adverse reactions. Disaccharidase inhibitors effectively compensate for the defective early-phase insulin release by slowing the production of sugars from carbohydrates. Thiazolidinediones appear to activate peroxisome proliferator-activated receptor gamma, which is involved in the metabolism of lipids. Short-acting insulin and the role of weight-loss agents are also discussed.

CONCLUSIONS

The availability of new options for diabetes therapy provides a chance for successful therapy in a larger number of patients. However, it is important to consider how much true benefit these new forms of treatment will have on the diabetic community. The best choice for a patient remains controversial.

Insulin lispro for the treatment of type 2 diabetes

Tight control can prevent complications in type 2 diabetes, and many patients will require insulin therapy to achieve this. Newer insulin formulations may offer some advantages with regard to patient convenience and a reduction in hypoglycaemia.

The role of sulphonylurea in combination therapy assessed in a trial of sulphonylurea withdrawal. Scandinavian Insulin-Sulphonylurea Study Group Research Team

AIMS

To evaluate the effect of adding insulin to sulphonylurea (SU) and the effect of SU withdrawal on glycaemic control in Type 2 diabetic patients who failed on treatment with SU alone.

METHOD

One hundred and seventy-five patients were included in a placebo-controlled multicentre study. During phase I (4 months), premixed insulin was added to glibenclamide therapy; during phase II (1-4 months, depending on response) the insulin dose was fixed, while placebo or glibenclamide replaced the open SU therapy. Insulin sensitivity (KITT), beta-cell function (C-peptide) and metabolic control (HbA1c) were monitored.

RESULTS

HbA1c improved from 9.65% to 7.23% (P < 0.0001) during phase I. A high HbA1c value (P < 0.0001) and a high KITT-value (P = 0.045) at baseline were associated with a beneficial response to combination treatment. During phase II, glycaemic control was unchanged in the control (glibenclamide) group. In the placebo group, after SU withdrawal, fasting blood glucose (FBG) increased by 10% or more within 4 weeks in 79% of the patients. Patients (67 of 112) with an FBG increase > or =40% during phase II were defined as 'SU responders' by protocol. In a multivariate analysis only a long duration of diabetes was associated with SU response. There were more GAD-antibody-positive patients among non-responders (18% vs. 4%, P = 0.0263).

CONCLUSIONS

Poor glycaemic control in combination with preserved insulin sensitivity and lack of GAD antibodies predicts a beneficial response to combination therapy, which can be achieved in 75% of patients with SU failure.

Oral glibenclamide suppresses glucagon secretion during insulin-induced hypoglycemia in patients with type 2 diabetes

Intensifying pharmacological therapy in patients with type 2 diabetes increases the risk of hypoglycemia and often requires the simultaneous use of more than one agent. Combining insulin and sulfonylurea is an effective and frequently used therapy in such patients. However, sulfonylurea derivatives have been shown to affect the release of glucagon, indicating a possible effect of such therapy on hormonal counterregulation to hypoglycemia. Thirteen patients receiving combined therapy were studied on two occasions: 1) after a wash-out period of glibenclamide (-GLIB), and 2) after resuming combined treatment for 6 months (+GLIB). We performed nonstep-wise, hyperinsulinemic hypoglycemic clamps using a constant i.v. insulin infusion and clamping blood glucose at 2.7 mmol/L (48 mg/dL) for 60 min. C Peptide levels were significantly higher during + GLIB, but no significant differences were seen in peripheral plasma insulin levels (+GLIB mean +/- SD, 70 +/- 17 mU/L vs. -GLIB, 75 +/- 14; P = 0.26). Epinephrine responses were similar in the two tests, but when glibenclamide was present the glucagon response was smaller, both the peak value (P = 0.016) and the incremental area under the curve (P = 0.011) as well as the total area under the curve (P = 0.016). These results suggest that intraislet insulin secretion is of importance for the alpha-cell responsiveness to hypoglycemia in these patients.

Combination Therapy For Type 2 Diabetes

OBJECTIVE

To discuss a rational approach to improvement of glycemic control in patients with type 2 diabetes mellitus with use of combination therapy.

METHODS

We review the mechanisms of action and clinical applications for the various antidiabetic agents alone and in various combinations. Relevant studies in the literature are reviewed.

RESULTS

Although diet and exercise remain the cornerstones of treatment, in most patients with type 2 diabetes, pharmacologic agents are needed to achieve optimal glycemic control and likely reduce the incidence of microvascular and possibly macrovascular complications as well. Sulfonylureas have long been the foundation of oral pharmacologic therapy and provide adequate glycemic control for most patients for 5 to 10 years or longer. In the past, when treatment with sulfonylureas was no longer effective, insulin therapy was inevitable. With the approval of several new pharmacologic agents for the treatment of type 2 diabetes, however, the addition of one or more orally administered agents to sulfonylurea therapy or use of other oral combination therapy is rapidly evolving as a means of optimizing glycemic control. In many patients, combination therapy can delay the need to add or switch to insulin, or it can enhance glycemic control in patients already receiving insulin. In selected patients treated solely with insulin, discontinuation of insulin treatment and reinitiation of oral therapy may even be possible.

CONCLUSION

Currently, four classes of orally administered antidiabetic agents are available for use in patients with type 2 diabetes: insulin secretagogues, biguanides, a-glucosidase inhibitors, and thiazolidinediones. By taking advantage of differing mechanisms of action, combination therapy is evolving as a means of optimizing glycemic control in patients in whom a single agent or insulin is inadequate. Combinations of orally administered agents can often delay the need for insulin or in combination with insulin aid in achieving glycemic goals. Continuing research will help optimize combination therapies even further.

Pharmacological management of diabetes: recent progress and future perspective in daily drug treatment

Glycaemic control in Type 1 diabetes has been proven efficient in preventing microvascular and neurological complications. The assumption that good control of hyperglycaemia may also have significant impact on alleviation of complications in Type 2 diabetes has gained growing support in recent years. Measures such as body weight reduction and exercise improve the metabolic defects, but pharmacological therapy is most frequently used. The sulphonylureas stimulate insulin secretion. Metformin and troglitazone increase glucose disposal and decrease hepatic glucose output without causing hypoglycaemia. Acarbose helps to spread the dietary carbohydrate challenge to endogenous insulin over time. These pharmacological treatments can improve blood glucose regulation in Type 2 diabetes patients. However, the key to strict glycaemic control with use of exogenous insulin lies in the creation of delivery methods that emulate physiologic insulin secretion. Insulin lispro, a recombinant insulin analogue, is identical to human insulin except for the transposition of proline and lysine at positions 28 and 29 in the C-terminus of the B chain. Evidence suggests that patients perceive their quality of life to be improved with insulin lispro when compared with regular human insulin, and that satisfaction with treatment is greater with the insulin analogue. Numerous new pharmacological approaches are under active investigation, with the aim of promoting insulin secretion, improving the action of insulin, or slowing carbohydrate absorption. With respect to continuous subcutaneous insulin infusion therapy and implantable pumps, despite that this approach is not widely utilised, it appears to bring us as close to achieving glycaemic control as is feasible with current treatment approaches. However, general application of such technology requires significant improvements in several areas, such as improvement of patency of catheter, pump failures due to early battery depletion incidents, and pump miniaturisation. Future perspective resides on insulin analogues with longer half-lives that would provide better basal insulin coverage in association with fast-acting analogues.

Combination Therapy with Insulin And Metformin

OBJECTIVE

To review the clinical usefulness of combination therapy with insulin and metformin.

METHODS

Basic considerations about the use of insulin in non-insulin-dependent diabetes mellitus (NIDDM) and the interaction of metformin with insulin are outlined. The clinical documentation of this therapeutic strategy is reviewed, with emphasis on controlled studies. In addition, the use of this drug combination in insulin-dependent diabetes mellitus (IDDM) is briefly addressed.

RESULTS

Insulin is used in patients with NIDDM when adequate plasma glucose control can no longer be maintained by orally administered agents. Metformin ameliorates insulin resistance, reduces hyperinsulinemia, and counteracts weight gain. It exerts an insulin-sparing and antihyperglycemic effect and may improve cardiovascular risk factors. Although these effects have been demonstrated consistently in several controlled studies, relatively few patients have been treated with insulin + metformin (with or without sulfonylurea). The combination is well tolerated, commonly used, and approved in several countries. No specific guidelines have been established for selection of patients, but obese patients with NIDDM who are receiving high doses of insulin are likely to benefit. Patients whose diabetes is poorly controlled by sulfonylurea or by combination oral therapy, not previously treated with insulin, may also be suitable candidates. Insulin administered at bedtime is a feasible approach, and a daily dose of 1.5 to 2.5 g of metformin seems adequate. Although the application may be questionable, metformin can also be added to insulin in the treatment of selected patients with IDDM.

CONCLUSION

Metformin is effective in conjunction with insulin in NIDDM. Because of its action on insulin resistance, it might be a more suitable adjunct to insulin than sulfonylurea in obese patients with NIDDM who are receiving high insulin doses, but it has been less well studied.

Combination insulin and sulfonylurea therapy in insulin-requiring type 2 diabetes mellitus

PURPOSE

To determine the effect(s) on glucose control, insulin dose, and circulating insulin levels of the addition of a sulfonylurea (glipizide) to the treatment regimen of patients with insulin-requiring type 2 diabetes mellitus.

PATIENTS AND METHODS

Thirty seven patients with type 2 diabetes mellitus taking insulin for at least 1 year prior to study and treated with > or = 40 U of insulin per day were recruited for a randomized, double-blind, placebo-controlled, crossover trial. Patients were treated with 3 months of insulin + placebo (I + P) and 3 months of insulin + glipizide (I + G), with an intermediate 1 month washout period using insulin therapy alone. Adjustments were made initially to the maximum dose of glipizide (40 mg/day), followed by insulin dose adjustments. Twenty-nine of the 37 patients demonstrated a significant C-peptide response to Ensure and were selected for analysis.

RESULTS

The fasting plasma glucose in the I + G arm was 6.8 (121.8 mg/dl) vs. 8.7 mmol/L (156.0 mg/dl) in the I + P arm, P < 0.001. Mean plasma glucose over 24 hours was 9.8 (176.9 mg/dl) for I + G vs. 11.3 mmol/L (203.8 mg/dl) for I + P, P < 0.001. Glycated hemoglobin was significantly different (9.8 I + G vs. 11.4% I + P, P < 0.008). The total daily insulin dose required was significantly lower with I + G (69.1 vs. 87.3 U, P < 0.0005). However, there were no significant differences in free insulin levels.

CONCLUSION

The addition of a sulfonylurea (glipizide) to insulin therapy in patients with insulin-requiring type 2 diabetes mellitus taking large doses of insulin results in a rapid and substantial improvement in glucose control despite a significant reduction in insulin dose. Therefore, this form of combination therapy should be considered for patients with the above characteristics whose diet and exercise programs are correct but whose response to insulin therapy is inadequate.

Evaluation of drug usage and expenditure in a hospital diabetes clinic

BACKGROUND

Diabetes mellitus is a major public health problem and often coexists with hypertension and dyslipidaemia. A prescription-based survey was conducted to examine the use of antidiabetic, antihypertensive and lipid lowering drugs in a hospital diabetes clinic. The expenditure incurred was also evaluated.

METHOD

Prescriptions issued from the diabetes clinic were collected for 4 consecutive weeks. Drugs were categorized into three main classes--antidiabetic, antihypertensive and lipid-lowering drugs. The unit cost of each drug and the total amount prescribed were used to estimate the total drug costs.

RESULTS

During the 4-week study period, 534 prescriptions were collected, of which 520 contained antidiabetic drugs. Oral hypoglycaemic agents were prescribed in 379 patients (72.9%). Sulphonylurea was used as a single agent in 119 (22.9%) patients, in combination with metformin in 219 (42%) patients and with insulin in 17 patients (3.3%). Among patients treated with sulphonylureas (n=342), glibenclamide (47.7%) and gliclazide (30.7%) were the main drugs prescribed. Metformin monotherapy was prescribed in only 31 patients (6%). Insulin treatment was prescribed in 141 (27%) patients and in combination with oral drugs in 23 patients (4.5%). Of the 534 prescriptions, 225 (42%) contained antihypertensive drugs. Calcium channel blocking agents and angiotensin converting enzyme inhibitors were the most commonly prescribed drugs in both monotherapy (n=155) and combination therapy (n=70). The antidiabetic and antihypertensive drugs accounted for 45% and 39% of the total drug expenditure, respectively. Lipid-lowering drugs were prescribed in 8% of the diabetic patients. Simvastatin and gemfibrozil were the most common drugs prescribed and accounted for 12% of the total drug expenditure.

CONCLUSION

The use of antidiabetic drugs represents a major burden on the health care system. The high proportions of patients requiring antihypertensive drugs and lipid lowering drugs further increase drug expenditure. Most of these treatments have been shown to improve clinical outcomes and quality of life, if used appropriately. The impacts of these long-term medications on health care financing require careful evaluation to assess their cost-effectiveness.

Efficacy of combination therapy in non-insulin dependent diabetes mellitus

Secondary failure of oral hypoglycaemic agents raises the dilemma of whether to institute therapy with insulin alone, or in combination. We reviewed our experience of combination therapy following secondary failure of oral hypoglycaemic therapy. Seventeen subjects were receiving combination therapy for 6 months or more. Such treatment was associated with a significant fall in HbA1C--from 10.7 +/- 0.38 per cent to 8.3 +/- 0.35 per cent (p < 0.01) after 6 months and remained significantly reduced at 12 months (8.7 +/- 0.34 per cent (p < 0.01)). Mean body weight, systolic and diastolic blood pressure were unchanged during treatment with adjuvant insulin therapy. Insulin therapy is a useful adjunct in the daily management of subjects with NIDDM who experience secondary failure of oral hypoglycaemic agents.

Can Response to Bedtime Insulin with Daytime Sulfonylurea Be Predicted in Patients with Type 2 Diabetes Mellitus?

Objective:

To determine characteristics predictive of response in patients with Type 2 diabetes mellitus (Type 2 DM) who demonstrate good or poor blood glucose control while receiving bedtime insulin with daytime sulfonylurea (BIDS) therapy.

Methods:

A retrospective chart review of patients with Type 2 DM receiving BIDS therapy was performed. The criterion for responders was the mean of two consecutively obtained glycosylated hemoglobin (Hb) concentrations being less than or equal to 10.2% (HbA1c ≤7.0%).

Setting:

A university-affiliated diabetes specialty clinic staffed consistently by a pharmacist diabetes educator, four endocrinologists, and a pharmacotherapy specialist.

Patients:

Thirty-one patients with Type 2 DM who were predominantly African-American and women who had documented regular follow-up examinations for more than 12 months while receiving BIDS therapy.

Data Collection and Measurements:

Gender, ethnicity, height, weight, calculated body mass index, age of onset of diabetes mellitus, duration of diabetes mellitus before BIDS therapy, pre-BIDS treatment regimen, dosages of NPH insulin and glyburide, glycosylated Hb concentration, fasting blood glucose concentration, and duration of BIDS therapy were recorded.

Results:

There were no differences in age of onset of diabetes mellitus, duration of diabetes mellitus before BIDS was initiated, duration of therapy with BIDS, or baseline glycosylated Hb concentration between responders (n = 15) and nonresponders (n = 16). Patients in the responder group weighed less, had a lower body mass index, required smaller dosages of both glyburide and NPH insulin, and achieved a lower fasting blood glucose concentration.

Conclusions:

In this study population, with the exception of body mass index, there was no difference in suggested clinical characteristics of response between responders and nonresponders.

Sulfonylureas

Sulfonylureas have been available for the treatment of non-insulin-dependent diabetes mellitus (NIDDM) since the 1950s. With the introduction of new oral agents, there is a tendency to discount the value of sulfonylurea therapy. Sulfonylureas have the advantage of multiple formulations, low costs, minimal side effects, and demonstrated efficacy in controlling hyperglycemia. The major disadvantage of sulfonylureas is secondary failure, which may occur with all oral agents as part of the progression of NIDDM. Sulfonylureas should continue to play an important role in the treatment of NIDDM.