Metabolic effects of mealtime insulin lispro in comparison to glibenclamide in early type 2 diabetes

WITHDRAWN: Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

The Cochrane Metabolic and Endocrine Disorders Group withdrew this review as of Issue 7, 2015 because of the involvement of one author (SS Lund) being employed in a pharmaceutical company. The authors of the review and the Cochrane Metabolic and Endocrine Disorders Group did not find that this was a breach of the rules of the Cochrane Collaboration at the time when it was published. However, after the publication of the review, the Cochrane Collaboration requested withdrawal of the review due to the employment of the author. A new protocol for a review to cover this topic will be published. This will have a new title and a markedly improved protocol fulfilling new and important developments and standards within the Cochrane Collaboration as well as an improved inclusion and search strategy making it necessary to embark on a completely new review project.

The editorial group responsible for this previously published document have withdrawn it from publication.

Cardiovascular safety of sulfonylureas: a meta-analysis of randomized clinical trials

AIM

Cardiovascular safety of sulfonylurea has been questioned by some authors. This article aims at collecting all available data on this issue from randomized trials.

METHODS

A meta-analysis was performed including all trials with a duration of at least 6 months, comparing a sulfonylurea with a non-sulfonylurea agent in type 2 diabetes. Major cardiovascular events (MACE) and mortality were retrieved and combined to calculate Mantel-Haenzel odds ratio (MH-OR).

RESULTS

Of the 115 selected trials, 62 reported information on MACE, and 30 reported at least one event. MH-OR for sulfonylurea was 1.08 [0.86-1.36], p = 0.52 (1.85 [1.20-2.87], p = 0.005, in the five trials vs. DPP4 inhibitors, no significant differences vs. other comparators). The MH-OR for myocardial infarction and stroke was 0.88 [0.75-1.04], p = 0.13 and 1.28 [1.03-1.60], p = 0.026, respectively. Mortality was significantly increased with sulfonylureas (MH-OR: 1.22 [1.01-1.49], p = 0.047).

CONCLUSIONS

In type 2 diabetes, the use of sulfonylureas is associated with increased mortality and a higher risk of stroke, whereas the overall incidence of MACE appears to be unaffected. Significant differences in cardiovascular risk could be present in direct comparisons with specific classes of glucose-lowering agents, such as DPP4 inhibitors, but this hypothesis needs to be confirmed in long-term cardiovascular outcomes trials. The results of this meta-analysis need to be interpreted with caution, mainly because of limitations in trial quality and under-reporting of information on cardiovascular events and mortality. However, the cardiovascular safety of sulfonylureas cannot be considered established unless it is evaluated in long-term cardiovascular outcomes trials.

The effect of adjusting for baseline hypoglycemia when analyzing hypoglycemia data: a systematic analysis of 15 diabetes clinical trials

BACKGROUND

Baseline hypoglycemia rates are generally not collected or included as a covariate in statistical models used for analyzing hypoglycemia data. The objective of the present study was to examine the effect of adjusting for baseline hypoglycemia on estimation efficiency and statistical power.

SUBJECTS AND METHODS

A post hoc analysis of data from 15 insulin trials, including patients with type 1 diabetes mellitus (T1DM) (n=210), previously insulin-treated type 2 diabetes mellitus (T2DM) (n=1,511), or T2DM and previously insulin-naive (n=1,075). Hypoglycemic episodes were analyzed with a negative binomial regression model.

RESULTS

Baseline nocturnal hypoglycemia rate was significantly correlated with post-baseline nocturnal hypoglycemia rate in previously insulin-treated patients with T1DM and T2DM (correlation range, 0.37-0.63; P<0.001). Adjusting for baseline hypoglycemia resulted in a reduction in the SE for negative binomial regression for previously insulin-treated patients with T1DM and T2DM (range, 2.2-11.8%) and increased statistical power. Modeling of lengthening the lead-in period increases the correlation between baseline and post-baseline hypoglycemia event rate and statistical power.

CONCLUSIONS

Baseline hypoglycemia rate is significantly correlated with post-baseline hypoglycemia rate for patients with diabetes treated with insulin prior to randomization. The length of the lead-in period can impact correlations between baseline and post-baseline data, and adjustment for baseline hypoglycemia may improve the estimation efficiency for hypoglycemia data analyses in clinical trials.

Sulphonylurea monotherapy for patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a growing health problem worldwide. Whether sulphonylureas show better, equal or worse therapeutic effects in comparison with other antidiabetic interventions for patients with T2DM remains controversial.

OBJECTIVES

To assess the effects of sulphonylurea monotherapy versus placebo, no intervention or other antidiabetic interventions for patients with T2DM.

SEARCH METHODS

We searched publications in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, LILACS and CINAHL (all until August 2011) to obtain trials fulfilling the inclusion criteria for our review.

SELECTION CRITERIA

We included clinical trials that randomised patients 18 years old or more with T2DM to sulphonylurea monotherapy with a duration of 24 weeks or more.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the risk of bias. The primary outcomes were all-cause and cardiovascular mortality. Secondary outcomes were other patient-important outcomes and metabolic variables. Where possible, we used risk ratios (RR) with 95% confidence intervals (95% CI) to analyse the treatment effect of dichotomous outcomes. We used mean differences with 95% CI to analyse the treatment effect of continuous outcomes. We evaluated the risk of bias. We conducted trial sequential analyses to assess whether firm evidence could be established for a 10% relative risk reduction (RRR) between intervention groups.

MAIN RESULTS

We included 72 randomised controlled trials (RCTs) with 22,589 participants; 9707 participants randomised to sulphonylureas versus 12,805 participants randomised to control interventions. The duration of the interventions varied from 24 weeks to 10.7 years. We judged none of the included trials as low risk of bias for all bias domains. Patient-important outcomes were seldom reported.First-generation sulphonylureas (FGS) versus placebo or insulin did not show statistical significance for all-cause mortality (versus placebo: RR 1.46, 95% CI 0.87 to 2.45; P = 0.15; 2 trials; 553 participants; high risk of bias (HRB); versus insulin: RR 1.18, 95% CI 0.88 to 1.59; P = 0.26; 2 trials; 1944 participants; HRB). FGS versus placebo showed statistical significance for cardiovascular mortality in favour of placebo (RR 2.63, 95% CI 1.32 to 5.22; P = 0.006; 2 trials; 553 participants; HRB). FGS versus insulin did not show statistical significance for cardiovascular mortality (RR 1.36, 95% CI 0.68 to 2.71; P = 0.39; 2 trials; 1944 participants; HRB). FGS versus alpha-glucosidase inhibitors showed statistical significance in favour of FGS for adverse events (RR 0.63, 95% CI 0.52 to 0.76; P = 0.01; 2 trials; 246 participants; HRB) and for drop-outs due to adverse events (RR 0.28, 95% CI 0.12 to 0.67; P = 0.004; 2 trials; 246 participants; HRB).Second-generation sulphonylureas (SGS) versus metformin (RR 0.98, 95% CI 0.61 to 1.58; P = 0.68; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 0.92, 95% CI 0.60 to 1.41; P = 0.70; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.79 to 1.18; P = 0.72; 4 trials; 1642 participants; HRB), meglitinides (RR 1.44, 95% CI 0.47 to 4.42; P = 0.52; 7 trials; 2038 participants; HRB), or incretin-based interventions (RR 1.39, 95% CI 0.52 to 3.68; P = 0.51; 2 trials; 1503 participants; HRB) showed no statistically significant effects regarding all-cause mortality in a random-effects model. SGS versus metformin (RR 1.47; 95% CI 0.54 to 4.01; P = 0.45; 6 trials; 3528 participants; HRB), thiazolidinediones (RR 1.30, 95% CI 0.55 to 3.07; P = 0.55; 7 trials; 4955 participants; HRB), insulin (RR 0.96, 95% CI 0.73 to 1.28; P = 0.80; 4 trials; 1642 participants; HRB) or meglitinide (RR 0.97, 95% CI 0.27 to 3.53; P = 0.97; 7 trials, 2038 participants, HRB) showed no statistically significant effects regarding cardiovascular mortality. Mortality data for the SGS versus placebo were sparse. SGS versus thiazolidinediones and meglitinides did not show statistically significant differences for a composite of non-fatal macrovascular outcomes. SGS versus metformin showed statistical significance in favour of SGS for a composite of non-fatal macrovascular outcomes (RR 0.67, 95% CI 0.48 to 0.93; P = 0.02; 3018 participants; 3 trials; HRB). The definition of non-fatal macrovascular outcomes varied among the trials. SGS versus metformin, thiazolidinediones and meglitinides showed no statistical significance for non-fatal myocardial infarction. No meta-analyses could be performed for microvascular outcomes. SGS versus placebo, metformin, thiazolidinediones, alpha-glucosidase inhibitors or meglitinides showed no statistical significance for adverse events. SGS versus alpha-glucosidase inhibitors showed statistical significance in favour of SGS for drop-outs due to adverse events (RR 0.48, 95% CI 0.24 to 0.96; P = 0.04; 9 trials; 870 participants; HRB). SGS versus meglitinides showed no statistical significance for the risk of severe hypoglycaemia. SGS versus metformin and thiazolidinediones showed statistical significance in favour of metformin (RR 5.64, 95% CI 1.22 to 26.00; P = 0.03; 4 trials; 3637 participants; HRB) and thiazolidinediones (RR 6.11, 95% CI 1.57 to 23.79; P = 0.009; 6 trials; 5660 participants; HRB) for severe hypoglycaemia.Third-generation sulphonylureas (TGS) could not be included in any meta-analysis of all-cause mortality, cardiovascular mortality or non-fatal macro- or microvascular outcomes. TGS versus thiazolidinediones showed statistical significance regarding adverse events in favour of TGS (RR 0.88, 95% CI 0.78 to 0.99; P = 0.03; 3 trials; 510 participants; HRB). TGS versus thiazolidinediones did not show any statistical significance for drop-outs due to adverse events. TGS versus other comparators could not be performed due to lack of data.For the comparison of SGS versus FGS no meta-analyses of all-cause mortality, cardiovascular mortality, non-fatal macro- or microvascular outcomes, or adverse events could be performed.Health-related quality of life and costs of intervention could not be meta-analysed due to lack of data.In trial sequential analysis, none of the analyses of mortality outcomes, vascular outcomes or severe hypoglycaemia met the criteria for firm evidence of a RRR of 10% between interventions.

AUTHORS' CONCLUSIONS

There is insufficient evidence from RCTs to support the decision as to whether to initiate sulphonylurea monotherapy. Data on patient-important outcomes are lacking. Therefore, large-scale and long-term randomised clinical trials with low risk of bias, focusing on patient-important outcomes are required.

Relationship of baseline HbA1c, HbA1c change and HbA1c target of < 7% with insulin analogues in type 2 diabetes: a meta-analysis of randomised controlled trials

AIM

We performed a meta-analysis of randomised controlled trials (RCTs) with insulin analogues in type 2 diabetes utilising a least-squared regression model in order to assess the relationship between baseline HbA1c, the magnitude of HbA1c decrease and attainment of HbA1c target of < 7%.

METHODS

Randomised controlled trials involving insulin regimens (basal, prandial, biphasic and basal-bolus) were identified through electronic searches (MEDLINE, EMBASE, CINAHL and The Cochrane Library) through September 2010. We included any study arm of RCTs if they were at least 12 weeks in duration; the number of patients in any arm was more than 30 and reported the baseline HbA1c and change from baseline HbA1c.

RESULTS

We found 87 studies, with a total of 135 arms, and 38,803 patients. The weighted R(2) values for the overall analysis assessing the association between baseline HbA1c and absolute change in HbA1c or the proportion of patients at target were 0.485 (p < 0.001) and 0.146 (p < 0.001), respectively. Subanalyses of insulin regimens for the association between basal HbA1c and absolute decrease of HbA1c produced weighted R(2), which were significant for all insulin regimens with the highest association for basal-bolus (R(2) = 0.719, p < 0.001).

CONCLUSIONS

The strong positive relationship between baseline HbA1c and the magnitude of HbA1c change we found in RCTs using insulin analogues in type 2 diabetes should be considered when assessing the clinical efficacy of insulin therapies.

Diabetes medications and body weight

Tight diabetes control sometimes comes with a price: weight gain and hypoglycemia. Two of the three major recent trials that looked at the relationship between intensive diabetes control and cardiovascular events reported significant weight gain among the intensively treated groups. There is a growing concern that the weight gain induced by most diabetes medications diminishes their clinical benefits. On the other hand, there is a claim that treating diabetes with medications that are weight neutral or induces weight loss or less weight gain while minimizing those that increase body weight may emerge as the future direction for treating overweight and obese patients with diabetes. This review clarifies the weight effect of each of the currently available diabetes medications, and explains the mechanism of action behind this effect. Despite the great variability among reviewed clinical trials, the currently available evidence is quite sufficient to demonstrate the change in body weight in association with most of the currently available medications. This review also provides some guidelines on using diabetes medications during weight management programs.

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.

A systematic review and meta-analysis of hypoglycemia and cardiovascular events: a comparison of glyburide with other secretagogues and with insulin

OBJECTIVE

Glyburide is the most widely used sulfonylurea but has unique pharmacodynamic properties that may increase harm. We hypothesized that glyburide causes more hypoglycemia and cardiovascular events than other secretagogues or insulin.

RESEARCH DESIGN AND METHODS

Data sources were Medline, Embase, Cochrane, and three other web-based clinical trial registers (1966-2005). Parallel, randomized, controlled trials in people with type 2 diabetes comparing glyburide monotherapy with monotherapy using secretagogues or insulin were selected. Outcomes were hypoglycemia, glycemic control, cardiovascular events, body weight, and death. Titles and abstracts of 1,806 publications were reviewed in duplicate and 21 relevant articles identified. Data on patient characteristics, interventions, outcomes, and validity were extracted in duplicate using predefined criteria.

RESULTS

Glyburide was associated with a 52% greater risk of experiencing at least one episode of hypoglycemia compared with other secretagogues (relative risk 1.52 [95% CI 1.21-1.92]) and with 83% greater risk compared with other sulfonylureas (1.83 [1.35-2.49]). Glyburide was not associated with an increased risk of cardiovascular events (0.84 [0.56-1.26]), death (0.87 [0.70-1.07]), or end-of-trial weight (weighted mean difference 1.69 kg [95% CI -0.41 to 3.80]) compared with other secretagogues. Limitations included suboptimal reporting of original trials. Loss to follow-up exceeded 20% in some studies, and major hypoglycemia was infrequently reported.

CONCLUSIONS

Glyburide caused more hypoglycemia than other secretagogues and other sulfonylureas. Glyburide was not associated with an increased risk of cardiovascular events, death, or weight gain.

Insulin Lispro

Insulin lispro, alone (Humalog) or as premixture (Humalog Mix25 or Humalog Mix50) is indicated for the treatment of hyperglycaemia in diabetes mellitus in many countries worldwide. It is a recombinant human insulin analogue and, except for the transposition of two amino acids, is identical to endogenous human insulin. Insulin lispro has a faster onset of action and shorter duration of activity than regular human insulin, and the time-action profile of insulin lispro mimics that of the physiological response of endogenous human insulin to food intake. In diabetic patients, from young children to the elderly, it has demonstrated postprandial blood glucose control similar to or better than that achieved with regular human insulin, without an increased risk of hypoglycaemia. In some trials, the risk of hypoglycaemia, including nocturnal episodes, was less in insulin lispro recipients than in regular human insulin recipients. Insulin lispro alone, or as a premixture with the longer-acting insulin neutral protamine lispro, can be administered immediately before or after meals. This convenient and flexible injection schedule may enable patients, including those with a non-routine lifestyle or unpredictable eating or exercising habits, to achieve the tight glycaemic control required to minimise long-term complications of diabetes and contributes to patient satisfaction with treatment.

The switch from sulfonylurea to preprandial short- acting insulin analog substitution has an immediate and comprehensive beta-cell protective effect in patients with type 2 diabetes mellitus

BACKGROUND

Supplementary insulin therapy provides assistance to meal-time insulin secretion in patients with type 2 diabetes and may have protective effects on beta-cell function.

METHODS

This study explored the immediate effect of supplementary insulin therapy on beta- cell function in patients with glimepiride monotherapy (five women, 15 men; 61.8 +/- 6.4 years old; body mass index, 31.1 +/- 4.4 kg/m(2); hemoglobin A1c, 7.0 +/- 1.3%). After 1 week of continued glimiperide therapy, the patients were randomized either to continue with their oral treatment or to switch to a fixed-dose supplementary insulin therapy (8 U of insulin aspart subcutaneously before each meal) for another week. Oral glucose tolerance tests (OGTTs) after drug uptake were performed at days 7 and 14, with measurement of glucose, insulin, C-peptide, intact and total proinsulin, glucagon, lactate, free fatty acids, and adiponectin.

RESULTS

Significant reductions from baseline were seen in the supplementary insulin therapy group for the fasting values of insulin (from 13.1 +/- 5.1 microU/mL to 10.6 +/- 5.2 microU/mL, P < 0.01), intact proinsulin (from 18.3 +/- 11.2 pmol/L to 10.3 +/- 4.6 pmol/L, P micro 0.05), total proinsulin (from 43.3 +/- 22.7 pmol/L to 29.7 +/- 14.5 pmol/L, P < 0.01), split proinsulin (from 24.9 +/- 13.8 pmol/L to 19.4 +/- 10.8 pmol/L, P micro 0.01), and the degree of beta-cell dysfunction (P < 0.05). Also, lower values for intact and total proinsulin and split proinsulin in the OGTT were observed in this group during the OGTT at the end point, while no changes at all occurred in the glimepiride group.

CONCLUSIONS

A fixed low-dose preprandial insulin aspart therapy resulted in an overall beta-cell protection with an improved fasting beta-cell secretion profile already within 1 week. Our study indicates that supplementary insulin therapy might be a reasonable alternative to bedtime basal insulin injections for initiation of insulin therapy in patients with type 2 diabetes.