Efficacy of Sulfonylureas with Insulin in Type 2 Diabetes Mellitus

A Practical Review of Diabetes Mellitus Type 2 Treatment in Primary Care

The treatment of diabetes mellitus type 2 (DM2) is becoming more complex as new medications are approved. Primary care providers must maintain their medical knowledge on emerging medications for best patient care. This review simplifies the non-insulin treatments of diabetes with an emphasis on the cardio-renal protectants, sodium-glucose cotransporter 2 (SGLT-2) inhibitors and glucagon-like peptide 1 receptor agonists (GLP-1).

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.

Dosing of U-100 insulin and associated outcomes among Medicare enrollees with type 1 or type 2 diabetes

Objective

To examine costs, resource utilization, adherence, and hypoglycemic events among various doses of U-100 insulin regimens among elderly patients (age ≥65 years) diagnosed with diabetes.

Methods

Truven Health Analytics Medicare databases from January 1, 2008 through December 31, 2011 were utilized. General linear models with a gamma distribution and log link were used to examine costs, while logistic and negative binomial regressions were used to examine resource utilization and hypoglycemic events. Analyses controlled for patient characteristics, pre-period comorbidities, general health, and use of antidiabetic medications as well as index dose of insulin.

Results

All-cause inpatient, emergency room, and outpatients costs, as well as diabetes-related inpatient costs, were highest among individuals who were treated with an index dose of 10–100 units/day followed by >300 units/day, while drug costs and total costs generally increased as index dosage increased. Resource utilization generally followed the same pattern as costs, with number of office visits increasing as the dose increased and the highest hospital length of stay, number of hospitalizations, number of emergency room visits, and number of diabetes-related hospitalizations were generally highest among those in the lowest and highest index dose cohorts. Compared to patients who initiated with an index dose of 10–100 units/day, all other patients were significantly less likely to achieve an adherence threshold of 80% based upon index dose range, and while those with an index dose of >100–150 units/day were significantly more likely to experience a hypoglycemic event.

Conclusion

These results suggest that, for elderly individuals with diabetes, there is a higher patient burden among those who receive the lowest and highest insulin doses.

Is beta-cell failure in type 2 diabetes mellitus reversible?

BACKGROUND:

In the UK Prospective Diabetes Study (UKPDS), many subjects maintained glycemic goal (HbA_1c < 7.0%) at 9 years, showing that β-cell function was preserved and that the initial decline in β-cell function recovered with sulphonylureas. Moreover, obese subjects using high daily doses of insulin for several years rarely require insulin or oral hypoglycemic agents to maintain their glycemic goal following weight loss achieved by gastric bypass surgery. Thus, declining β-cell function during the course of type 2 diabetes mellitus (T2DM) is neither universal nor permanent.

OBJECTIVE:

To assess β-cell function in morbidly obese subjects before insulin withdrawal and on attaining the glycemic goal with weight loss and oral agents.

MATERIALS AND METHODS:

Serum C-peptide (CPEP) and glucose (G) concentrations were determined up to 180 min during an oral glucose tolerance test (OGTT) with 75 glucose in 10 obese men with T2DM, before insulin withdrawal, and on achieving the glycemic goal with metformin, glimepiride, and weight loss. Ten age-matched healthy men participated as controls. Cumulative responses (CR) of CPEP and G were calculated by adding differences between the level at each time-period during OGTT and fasting (F) concentration. β-Cell function was expressed as the FCPEP as well as the insulinogenic index (CRCPEP/CRG). Insulin sensitivity was determined as FCEP × FG.

RESULTS:

FCPEP was decreased, though still present, prior to insulin withdrawal. Moreover, on attaining the glycemic goal over 6-9 months, FCPEP, CRPEP/CRG, and FCPEP × FG improved markedly (P < 0.001).

CONCLUSION:

Decline in β-cell function in morbidly obese T2DM may not be progressive and is reversible on improving insulin sensitivity and on eliminating the inhibition by exogenous insulin.

The role of glimepiride in the treatment of type 2 diabetes mellitus

IMPORTANCE OF THE FIELD

Type 2 diabetes mellitus (T2DM) is increasingly prevalent throughout the world; controlling glycemia is an important part of preventing serious complications of diabetes. Sulfonylureas have been used in the treatment of type 2 diabetes for many years.

AREAS COVERED IN THIS REVIEW

This article reviews the pharmacological and clinical aspects of glimepiride, a second-generation sulfonylurea. Literature search was conducted in PubMed, and articles selected for relevance to pharmacology or clinical efficacy data from 1994 to 2009, with older references sought as indicated.

WHAT THE READER WILL GAIN

Pharmacology of glimepiride, data regarding clinical efficacy, key comparisons to other agents and emerging concepts related to glimepiride are discussed.

TAKE HOME MESSAGE

Therapy with glimepiride improves the relative insulin secretory deficit found in T2DM, has antihyperglycemic efficacy equal to other secretagogues with reduced potential for hypoglycemia and may have additional actions contributing to glycemic control in T2DM.

Insulin therapy in type 2 diabetes: what is the evidence?

AIM

To systematically review the literature regarding insulin use in patients with type 2 diabetes mellitus

METHODS

A Medline and Embase search was performed to identify randomized controlled trials (RCT) published in English between 1 January 2000 and 1 April 2008, involving insulin therapy in adults with type 2 diabetes mellitus. The RCTs must comprise at least glycaemic control (glycosylated haemoglobin (HbA1c), postprandial plasma glucose and /or fasting blood glucose (FBG)) and hypoglycaemic events as outcome measurements.

RESULTS

The Pubmed search resulted in 943 hits; the Embase search gave 692 hits. A total of 116 RCTs were selected by title or abstract. Eventually 78 trials met the inclusion criteria. The studies were very diverse and of different quality. They comprised all possible insulin regimens with and without combination with oral medication. Continuing metformin and/or sulphonylurea after start of therapy with basal long-acting insulin results in better glycaemic control with less insulin requirements, less weight gain and less hypoglycaemic events. Long-acting insulin analogues in combination with oral medication are associated with similar glycaemic control but fewer hypoglycaemic episodes compared with NPH insulin. Most of the trials demonstrated better glycaemic control with premix insulin therapy than with a long-acting insulin once daily, but premix insulin causes more hypoglycaemic episodes. Analogue premix provides similar HbA1c, but lower postprandial glucose levels compared with human premix, without increase in hypoglycaemic events or weight gain. Drawing conclusions from the limited number of studies concerning basal-bolus regimen seems not possible. Some studies showed that rapid-acting insulin analogues frequently result in a better HbA1c or postprandial glucose without increase of hypoglycaemia than regular human insulin.

CONCLUSION

A once-daily basal insulin regimen added to oral medication is an ideal starting point. All next steps, from one to two or even more injections per day should be taken very carefully and in thorough deliberation with the patient, who has to comply with such a regimen for many years.

Comparative efficacy of glimepiride and/or metformin with insulin in type 2 diabetes

BACKGROUND AND AIMS

The data regarding comparison of efficacy of metformin with glimepiride, newest Sulfonylurea, or with the use of both drugs in combination with insulin is rare in the literature. Therefore, we assessed the daily insulin dose, hypoglycemic events and body weight on achieving desirable glycemic control after addition of insulin, to glimepiride 8 mg and/or metformin 2500 mg, in subjects with type 2 DM manifesting lapse of glycemic control.

METHODS

S.C. insulin Novolog Mix [70/30], pre-supper was initiated in 12 subjects on metformin, 14 subjects on glimepiride, and 12 subjects receiving both drugs, with HbA1C > 7.5% and eight subjects receiving placebo. Insulin dose was increased by 4 U at weekly interval until fasting blood sugar [FBS] between 6.6 and 8 mM/l was attained and then further titrated by 2 U every week to attain and maintain FBS between 4.5 and 6.7 mM/l over the next 4 months. The comparisons were conducted between these groups for HbA1C, the daily insulin dose, body weight noted at the end of this study period as well as the hypoglycemic episodes per patient during the last 4 weeks of the study period.

RESULTS

HbA1C levels were < 7.0% in all subjects at the end of the study. The daily insulin dose (units), total and per kg/BW was significantly lower [p < 0.001] with metformin (51 +/- 5, 0.51 +/- 0.10), glimepiride (40 +/- 4, 0.42 +/- 0.09) as well as with both drugs (23 +/- 7, 0.21 +/- 0.07) in comparison to placebo (82 +/- 10, 0.82 +/- 0.12). The insulin dose was also significantly lower [p < 0.05] in subjects on both drugs than subjects receiving them individually. Weight gain was less [p < 0.001] with metformin [2.5 +/- 0.74 kg], glimepiride [2.3 +/- 0.7 kg], and both drugs [2.2 +/- 0.61 kg] in comparison to placebo [5.2 +/- 1.4 kg] whereas the hypoglycemic episodes were lesser with metformin (3.8 +/- 1.2) and glimepiride (3.3 +/- 0.9) and least with both drugs (2.5 +/- 0.6) in comparison to placebo (5.2 +/- 1.0).

CONCLUSION

Glimepiride and metformin are effective individually in achieving a glycemic goal with a less daily insulin dose, weight gain, and hypoglycemic episodes in comparison to insulin monotherapy in subjects with type 2 diabetes mellitus with further marked reduction in these parameters when used concurrently.

Medications Associated with Weight Gain

OBJECTIVE

To review available literature regarding weight gain associated with commonly prescribed drugs and adjunctive therapy used to limit weight gain.

DATA SOURCES

Information was retrieved from a MEDLINE English-literature search between 1995 and July 2005, with a major subject heading of weight gain/drug effects excluding complementary alternative medicines. Other limits applied included human subjects and individuals >19 years of age. Additionally, references from retrieved articles were reviewed to identify other literature sources.

STUDY SELECTION AND DATA EXTRACTION

Changes in weight are generally reported as a primary or secondary outcome of many studies. Where possible, prospective, randomized, controlled trials were preferred; however, many studies were retrospective or open label. Meta-analyses and recent reviews, especially those providing a detailed description of the proposed mechanism involved in weight gain beyond the scope of this article, were included. Limited information was available from case reports. Studies were categorized by therapeutic area including psychiatry, neurology, diabetes, and other miscellaneous drug therapy. Medications used to intentionally stimulate appetite for weight gain, such as megesterol acetate, were not included.

DATA SYNTHESIS

Weight gain with medication is usually associated with individual agents within a class. The tendency to cause weight gain is often related to differential specificity and sensitivity of binding to receptors involved with appetite regulation.

CONCLUSIONS

Clinically significant weight gain is associated with some commonly prescribed medicines. There is wide interindividual variation in response and variation of the degree of weight gain within drug classes. Where possible, alternative therapy should be selected, especially for individuals predisposed to overweight and obesity.