Early combination therapy for the treatment of type 2 diabetes mellitus: systematic review and meta-analysis.

AIMS: Guidelines for type 2 diabetes recommend add-on agents when metformin alone fails to provide adequate glycaemic control. However, early combination therapy may benefit health outcomes. We conducted a systematic review and meta-analysis to investigate this question. METHODS: We searched MEDLINE and Cochrane CENTRAL (up to July 2012) without language restrictions. We sought randomized controlled trials (RCTs) evaluating initial combination therapy with metformin versus metformin monotherapy in patients with untreated type 2 diabetes. Weighted mean differences (WMDs) for changes from baseline and relative risks (RRs) [with 95% confidence intervals (CIs)] were calculated using random-effects model. RESULTS: In 15 RCTs (N = 6693), the mean age range was 48.4-62.7 years; mean baseline glycosylated haemoglobin (A1c) was 7.2-9.9% and mean diabetes duration was 1.6-4.1 years, with median follow-up of 6 months and with 13 comparisons for A1c change, 14 comparisons for A1c goal attainment of <7% and 13 comparisons for change in fasting plasma glucose (FPG). Drugs combined with metformin included thiazolidinediones (TZDs), insulin secretagogues, dipeptidyl peptidase-4 (DPP-4) inhibitors or sodium glucose transporterase (SGLT-2) inhibitors. Compared to metformin alone, combination therapy with metformin provided statistically significant reductions in A1c (WMD -0.43%, 95% CI -0.56, -0.30), increases in attainment of A1c goal of less than 7% (RR 1.40, 95% CI 1.33-1.48) and reductions in FPG (WMD -14.30 mg/dl, 95% CI -16.09, -12.51). CONCLUSIONS: These results suggest a potential benefit of initial combination therapy on glycaemic outcomes in diabetes compared to metformin monotherapy across a wide range of baseline A1c levels. Further research should explore if early combination treatment may also affect longer term health outcomes in diabetes.

Sulphonylureas and risk of cardiovascular disease: systematic review and meta-analysis.

AIMS: Sulphonylurea use has been linked with increased cardiovascular disease risk; however, previous studies have been inconsistent. Type 2 diabetes independently increases risk for cardiovascular disease, so understanding the link between longer-term use of anti-diabetic medications and cardiovascular disease has important clinical implications. METHODS: Literature search in MEDLINE and CENTRAL was conducted throughout December 2011 for clinical and observational studies that reported the association between sulphonylurea and cardiovascular disease events. Ratios (relative risk, odds ratios or hazard ratios) adjusted for potential confounders (concomitant medications, baseline cardiovascular risk, diabetes severity) were pooled using a random-effects model to yield relative risks and associated 95% confidence intervals. RESULTS: This meta-analysis included 33 studies (n = 1,325,446 patients), followed for a range of 0.46-10.4 years. In all studies, compared with other oral diabetes drugs, sulphonylurea use was associated with a significantly increased risk of cardiovascular death (relative risk 1.27, 95% confidence interval 1.18-1.34, n = 27 comparisons) and composite cardiovascular event (including myocardial infarction, stroke, cardiovascular-related hospitalization or cardiovascular death) (relative risk 1.10, 95% confidence interval 1.04-1.16, n = 43 comparisons). In studies comparing sulphonylurea vs. metformin, these relative risks were 1.26 (95% confidence interval 1.17-1.35, n = 17 comparisons) and 1.18 (95%confidence interval 1.13-1.24, n = 16 comparisons), respectively. CONCLUSIONS: Results suggest that sulphonylurea use may elevate the risk of cardiovascular disease among patients with diabetes. This meta-analysis expands the pool of studies evaluating cardiovascular mortality compared with prior observations while using adjusted estimates, and assessing an additional outcome of a composite cardiovascular event. This finding warrants consideration in clinical practice when other treatment options may be available.

Effect of long term low-fat dietary intervention on change in hemostatic factors: results from the Women's Health Initiative.

Low-fat diet may play a role in prevention of cardiovascular disease (CVD) by altering the levels of hemostatic factors. There are yet limited data on the effects of low-fat diet on the circulating levels of these factors and existing studies are limited by small sample size and short duration of follow-up. We conducted an analysis in a subset of women (active arm = 723; control arm = 1036) within the Women's Health Initiative Dietary Modification Trial to investigate the long term effect of a low-fat diet on circulating levels of fibrinogen, factor VII concentration and factor VII activity among postmenopausal women aged 50-79 years. Using linear mixed effects model with random intercept and data from three follow-up visits (years 1, 3 and 6) we evaluated the change in each factor over time. Overall, the changes in these factors were small (less than 5%) in both the arms of the trials at the end of intervention and there was no significant difference in mean change between the two arms. Our results indicate that the low-fat dietary intervention was not associated with significant changes in hemostatic factors among postmenopausal women.

Biomarkers of body iron stores and risk of developing type 2 diabetes.

AIM: Iron may contribute to the pathogenesis of type 2 diabetes mellitus (DM) by inducing oxidative stress and interfering with insulin secretion. Elevated ferritin levels are associated with increased DM risk among healthy individuals. However, it is yet unknown if ferritin predicts DM incidence among high-risk individuals with impaired glucose tolerance (IGT). Furthermore, the association between soluble transferrin receptors (sTfR), a novel marker of iron status, and DM risk has not yet been prospectively investigated in these individuals. We conducted this study to evaluate the association between baseline levels of ferritin and sTfR and the risk of developing DM among overweight and obese individuals at high risk of DM. METHODS: This nested case-control study (280 cases and 280 matched controls) was conducted within the placebo arm of the Diabetes Prevention Program, is a clinical trial conducted among overweight/obese individuals with IGT. Ferritin and sTfR levels were measured by immunoturbidimetric assays. Incident DM was ascertained by annual 75-g oral glucose tolerance test and semi-annual fasting glucose. RESULTS: Compared with controls, cases had higher sTfR levels (3.50 +/- 0.07 vs. 3.30 +/- 0.06 mg/l; p = 0.03), but ferritin levels were not statistically different. The multivariable odds ratios (OR) and 95% confidence intervals (95% CI) for DM incidence comparing highest with the lowest quartiles of sTfR was 2.26 (1.37-4.01) (p-trend: 0.008). CONCLUSIONS: Modestly elevated sTfR levels are associated with increased DM risk among overweight and obese individuals with IGT. Future studies should evaluate factors determining sTfR levels and examine if interventions that lower body iron stores reduce DM incidence.