Caterina Lamanna

Effect of metformin on cardiovascular events and mortality: a meta-analysis of randomized clinical trials

Aim: Some studies suggested that metformin could reduce cardiovascular risk to a greater extent than that determined by glucose reduction. Aim of the present meta‐analysis is to assess the effects of metformin on the incidence of cardiovascular events and mortality.

DPP-4 inhibitors and lipids: systematic review and meta-analysis.

IntroductionLipid profile is an important determinant of cardiovascular risk in type 2 diabetic patients. Available glucose-lowering agents can affect lipid levels. Dipeptidyl peptidase-4 (DPP-4) inhibitors have been reported to reduce total cholesterol, but results are inconsistent across trials. The present metaanalysis was designed to assess the effect of DPP-4 inhibitors on blood lipids, verifying possible differences across compounds of this class.MethodsAn extensive search of Medline and the Cochrane Library (any date up to December 31, 2010, restricted to randomized clinical trials, published in English) was performed for all trials containing, in any field, the words “sitagliptin,” “vildagliptin,” “saxagliptin,” “alogliptin,” “linagliptin,” and/or “dutogliptin.” Completed but unpublished trials were identified through a search of the ClinicalTrials.gov website, using the same keywords as above. Differences in the endpoint levels and absolute or percent variations of lipids were assessed. A metaregression was performed on the trials specified above to assess the effect of putative moderators on the effect of DPP-4 inhibitors on plasma lipids, considering all drugs together and each one separately.ResultsAlthough the number of trials of appropriate size and duration was high (n=53), only a small fraction of those (n=17) reported data on endpoint total, high-density lipoprotein, and low-density lipoprotein cholesterol, and triglyceride. The difference-in-means for endpoint versus baseline total cholesterol in patients on DPP-4 inhibitors treatment was significantly higher in comparison with controls, meaning that treatment with DPP-4 inhibitors is associated with a significant reduction in total cholesterol (−0.18 [−0.29; −0.06] mmol/L (−7.0 [−11.2; −2.50] mg/dL); P=0.002).ConclusionsThis meta-analysis suggests a possible beneficial effect of DPP-4 inhibitors on cholesterol, which, although small, could contribute to the reduction of cardiovascular risk.

Glucagon-Like Peptide-1 Receptor Agonists and Cardiovascular Events: A Meta-Analysis of Randomized Clinical Trials

Objective. Data from randomized clinical trials with metabolic outcomes can be used to address concerns about potential issues of cardiovascular safety for newer drugs for type 2 diabetes. This meta-analysis was designed to assess cardiovascular safety of GLP-1 receptor agonists. Design and Methods. MEDLINE, Embase, and Cochrane databases were searched for randomized trials of GLP-1 receptor agonists (versus placebo or other comparators) with a duration ≥12 weeks, performed in type 2 diabetic patients. Mantel-Haenszel odds ratio with 95% confidence interval (MH-OR) was calculated for major cardiovascular events (MACE), on an intention-to-treat basis, excluding trials with zero events. Results. Out of 36 trials, 20 reported at least one MACE. The MH-OR for all GLP-1 receptor agonists was 0.74 (0.50–1.08), P = .12 (0.85 (0.50–1.45), P = .55, and 0.69 (0.40–1.22), P = .20, for exenatide and liraglutide, resp.). Corresponding figures for placebo-controlled and active comparator studies were 0.46 (0.25–0.83), P = .009, and 1.05 (0.63–1.76), P = .84, respectively. Conclusions. To date, results of randomized trials do not suggest any detrimental effect of GLP-1 receptor agonists on cardiovascular events. Specifically designed longer-term trials are needed to verify the possibility of a beneficial effect.

DOSES OF INSULIN AND ITS ANALOGUES AND CANCER OCCURRENCE IN INSULIN-TREATED TYPE 2 DIABETIC PATIENTS

OBJECTIVE Recent epidemiological studies suggested that some insulin analogues could be associated with increased risk of cancer. The present study is aimed at assessing the long-term association of different insulin analogues with cancer incidence. RESEARCH DESIGN AND METHODS A nested case-control study dataset was generated from the cohort study dataset (n = 1,340 insulin-treated diabetic outpatients) by sampling control subjects from the risk sets. For each case subject, the control subjects (up to five) were chosen randomly from those members of the cohort who are at risk for the same follow-up time of the case subject. Five-year age classes, sex, and BMI classes (<18.5, 18.5–24.9, 25–29.9, and ≥30 kg/m2) were considered as additional categorical matching variables. RESULTS During a median follow-up of 75.9 months (interquartile range 27.4–133.7), 112 case subjects of incident cancer were compared with 370 matched control subjects. A significantly higher mean daily dose of glargine was observed in case subjects than in control subjects (0.24 IU/kg/day [0.10–0.39] versus 0.16 IU/kg/day [0.12–0.24], P = 0.036). Incident cancer was associated with a dose of glargine ≥0.3 IU/kg/day even after adjusting for Charlson comorbidity score, other types of insulin administration, and metformin exposure (odds ratio 5.43 [95% CI 2.18–13.53], P < 0.001). No association between incident cancer and insulin doses was found for human insulin or other analogues. CONCLUSIONS The possibility of association between cancer and higher glargine doses suggests that dosages should always be considered when assessing the possible association of insulin and its analogues with cancer.

Pioglitazone and cardiovascular risk. A comprehensive meta-analysis of randomized clinical trials

Aim:  The aim of this meta‐analysis of randomized clinical trials (RCT) was to assess whether pioglitazone is also associated with increased cardiovascular risk, as recently reported for rosiglitazone.

Liver enzymes and risk of diabetes and cardiovascular disease: Results of the Firenze Bagno a Ripoli (FIBAR) study

The aim of the study was to assess gamma-glutamyl transpeptidase (gamma-GT), alanine aminotransferase, and aspartate aminotransferase (AST) in the prediction of diabetes and cardiovascular disease (CVD) in subjects free from hepatic diseases other than nonalcoholic fatty liver disease. The present analysis was performed on the cohort of subjects enrolled in the Firenze Bagno a Ripoli (FIBAR) study, a screening program for diabetes performed between 1 March 2001 and 31 December 2003 in the city of Florence on 3124 subjects who underwent an oral glucose tolerance test. Incident cases of diabetes in nondiabetic subjects (n = 2662) were obtained through databases of drug prescriptions, hospital admissions, and lists of subjects eligible for reimbursement. Incident CVD in subjects free of diabetes and CVD at enrollment (n = 2617) was identified through hospital admissions and through the register of causes of death. Mean follow-up was 39.6 +/- 12.0 months and 39.8 +/- 11.4 months for diabetes and CVD, respectively. Yearly incidence of diabetes and CVD was 0.4% and 0.2%, respectively. After adjustment for age and sex, gamma-GT >40 U/L was associated with increased incidence of diabetes and CVD (hazard ratio [95% confidence interval]: 2.54 [1.26-5.11], P < .05 and 2.21 [0.98-5.43], P < .10, respectively). Risk of diabetes, but not of CVD, was increased in patients with gamma-GT in the 25- to 40-U/L range. After adjustment for confounders, AST >40 U/L predicted CVD (hazard ratio, 6.5 [95% confidence interval, 1.5-28.1]), but not diabetes. Elevated gamma-GT or AST is an independent predictor of CVD. An increase of gamma-GT levels above the reference range, or also in the upper reference range, is an independent predictor of incident diabetes.

Rosiglitazone and Risk of Cancer: A meta-analysis of randomized clinical trials

OBJECTIVE—Despite experimental data suggesting a protective effect of peroxisome proliferator–activated receptor-γ agonists with respect to malignancies, results of available epidemiological studies on the incidence of cancer in rosiglitazone-treated patients are not univocal. The aim of this meta-analysis of randomized clinical trials is to assess the effect of rosiglitazone on the incidence of cancer. RESEARCH DESIGN AND METHODS—Randomized clinical trials of rosiglitazone with duration of >24 weeks were retrieved through Medline and from the GlaxoSmithKline Web site, which reports main results of all trials sponsored by GlaxoSmithKline; incident malignancies were retrieved from the summary of serious adverse events. Proportions of outcome measures across treatment groups were compared by odds ratios (ORs) and 95% CI. Considering differences in the duration of follow-up among treatment arms in some of the trials, we also calculated the incidence of cancer in rosiglitazone and control groups. RESULTS—Eighty trials, enrolling 16,332 and 12,522 patients in the rosiglitazone and comparator groups, respectively, were retrieved. Rosiglitazone was not associated with a significant modification of the risk of cancer (OR 0.91 [95% CI 0.71–1.16], P = 0.44). The incidence of malignancies was significantly lower in rosiglitazone-treated patients than in control groups (0.23 [0.19–0.26] vs. 0.44 [0.34–0.58] cases/100 patient-years; P < 0.05). CONCLUSIONS—The use of rosiglitazone appears to be safe in terms of incidence of cancer, whereas its possible protective effect needs to be further investigated.

Are sulphonylureas all the same? A cohort study on cardiovascular and cancer‐related mortality

Aim of the present study is the comparison of all‐cause, cardiovascular and non‐cardiovascular mortality, and cardiac morbidity, between patients treated with glibenclamide and gliclazide.

Three-year mortality in diabetic patients treated with different combinations of insulin secretagogues and metformin.

Several studies have shown an increase of mortality in diabetic patients treated with combinations of sulphonylureas and biguanides. Comparisons between different insulin secretagogues in combination with metformin with respect to all‐cause mortality have not been reported so far.

Cardiac safety profile of rosiglitazone: A comprehensive meta-analysis of randomized clinical trials

BACKGROUND Some meta-analyses of randomized clinical trials suggested that rosiglitazone could be associated with increased risk for myocardial infarction (MI). Available meta-analyses, based on studies sponsored by GlaxoSmithKline (GSK), failed to include all trials performed with rosiglitazone. Aim of this analysis is the assessment of the cardiovascular risk with rosiglitazone, using a comprehensive data set. METHODS Results of 164 trials with duration >4 weeks were retrieved from http://ctr.gsk.co.uk/welcome.asp and from Medline, while unpublished studies were identified from www.clinicaltrials.gov. A total of 164 trials (42,922 and 45,483 patient years for rosiglitazone and comparators, respectively) were included in the analysis. RESULTS The OR for all-cause and cardiovascular mortality with rosiglitazone was 0.93[0.76;1.14] and 0.94[0.68;1.29], respectively; rosiglitazone-associated risk for nonfatal MI and heart failure was 1.14[0.90;1.45] and 1.69[1.21;2.36], respectively. The risk of heart failure was higher (2.20[1.28;3.78]) when rosiglitazone was administered as add-on therapy to insulin. CONCLUSIONS Figures for rosiglitazone-associated risk for myocardial infarction could be lower than those previously reported on the basis of a smaller number of clinical trials. No increase of all-cause or cardiovascular mortality were observed with rosiglitazone. Conversely, treatment with rosiglitazone is associated with a relevant increase in the risk of heart failure, particularly in insulin-treated patients.