Reducing cardiovascular disease risk in patients with type 2 diabetes and concomitant macrovascular disease: can insulin be too much of a good thing?

Improvement of Vascular Insulin Sensitivity by Ranolazine

Ranolazine (RN) is a drug used in the treatment of chronic coronary ischemia. Different clinical trials have shown that RN behaves as an anti-diabetic drug by lowering blood glucose and glycosylated hemoglobin (HbA1c) levels. However, RN has not been shown to improve insulin (IN) sensitivity. Our study investigates the possible facilitating effects of RN on the actions of IN in the rabbit aorta. IN induced vasodilation of the abdominal aorta in a concentration-dependent manner, and this dilatory effect was due to the phosphorylation of endothelial nitric oxide synthase (eNOS) and the formation of nitric oxide (NO). On the other hand, IN facilitated the vasodilator effects of acetylcholine but not the vasodilation induced by sodium nitroprusside. RN facilitated all the vasodilatory effects of IN. In addition, IN decreased the vasoconstrictor effects of adrenergic nerve stimulation and exogenous noradrenaline. Both effects were in turn facilitated by RN. The joint effect of RN with IN induced a significant increase in the ratio of p-eNOS/eNOS and pAKT/AKT. In conclusion, RN facilitated the vasodilator effects of IN, both direct and induced, on the adrenergic system. Therefore, RN increases vascular sensitivity to IN, thus decreasing tissue resistance to the hormone, a key mechanism in the development of type II diabetes.

Usefulness of Glucagon-Like Peptide-1 Receptor Agonists to Reduce Adverse Cardiovascular Disease Events in Patients with Type 2 Diabetes Mellitus

Evidence suggests glucagon-like peptide-1 receptor agonists (GLP-1 RA) reduce cardiovascular disease (CVD) events. The objective of this study was to analyze randomized controlled trials (RCT) testing GLP-1 RA's effect on CVD events among participants with type 2 diabetes (T2DM). RCTs comparing GLP-1 RA versus placebo were identified using the PubMed and Cochrane databases. The endpoints in this study included major adverse cardiovascular events (MACE; a composite of cardiovascular death, nonfatal myocardial infarction (MI), and nonfatal stroke), and the individual components of MACE. The primary analysis calculated risk ratios (RR) and 95% confidence intervals (CI) for each endpoint. Heterogeneity for each endpoint was calculated using Chi² and I² tests. For any endpoint with significant heterogeneity, a meta-regression was performed using mean baseline hemoglobin A1C (A1C) as the moderator and a R² value was calculated. Seven RCTs (N = 56,004) were identified with 174,163 patient-years of follow-up. GLP-1 RA reduced MACE [RR 0.89, 95% CI 0.83 to 0.95], cardiovascular death [RR 0.88, 95% CI 0.81 to 0.95], and nonfatal stroke [RR 0.85, 95% CI 0.77 to 0.95]. There was no statistically significant heterogeneity among these RCTs. GLP-1 RA did not reduce nonfatal MI [RR 0.91, 95% CI 0.81 to 1.02]. However, there was significant heterogeneity among these RCTs (Chi² = 12.68, p = 0.05, I² = 53%). When accounting for baseline A1C in the regression model, there was no longer significant heterogeneity for this endpoint (p = 0.23, I² = 27%). A potential linear relationship between baseline A1C and GLP-1 RA's effect on nonfatal MI (R² = 0.64) was observed. In conclusion, GLP-1 RA reduced MACE, cardiovascular death, and nonfatal stroke; GLP-1 RA did not reduce nonfatal MI, however there may be a linear association between baseline A1C and GLP-1 RA's effect on nonfatal MI.

Insulin: too much of a good thing is bad

BACKGROUND

Insulin shares a limited physiological concentration range with other endocrine hormones. Not only too low, but also too high systemic insulin levels are detrimental for body functions.

MAIN BODY

The physiological function and clinical relevance of insulin are usually seen in association with its role in maintaining glucose homeostasis. However, insulin is an anabolic hormone which stimulates a large number of cellular responses. Not only too low, but also excess insulin concentrations are detrimental to the physiological balance. Although the glucoregulatory activity of insulin is mitigated during hyperinsulinemia by dampening the efficiency of insulin signaling ("insulin resistance"), this is not the case for most other hormonal actions of insulin, including the promotion of protein synthesis, de novo lipogenesis, and cell proliferation; the inhibition of lipolysis, of autophagy-dependent cellular turnover, and of nuclear factor E2-related factor-2 (Nrf2)-dependent antioxidative; and other defense mechanisms. Hence, there is no general insulin resistance but selective impairment of insulin signaling which causes less glucose uptake from the blood and reduced activation of endothelial NO synthase (eNOS). Because of the largely unrestricted insulin signaling, hyperinsulinemia increases the risk of obesity, type 2 diabetes, and cardiovascular disease and decreases health span and life expectancy. In epidemiological studies, high-dose insulin therapy is associated with an increased risk of cardiovascular disease. Randomized controlled trials of insulin treatment did not observe any effect on disease risk, but these trials only studied low insulin doses up to 40 IU/day. Proof for a causal link between elevated insulin levels and cardiovascular disease risk comes from Mendelian randomization studies comparing individuals with genetically controlled low or high insulin production.

CONCLUSIONS

The detrimental actions of prolonged high insulin concentrations, seen also in cell culture, argue in favor of a lifestyle that limits circadian insulin levels. The health risks associated with hyperinsulinemia may have implications for treatment regimens used in type 2 diabetes.

Pathogenesis of non-alcoholic fatty liver disease and implications on cardiovascular outcomes in liver transplantation

Along with the obesity epidemic there has been a major increase in non-alcoholic fatty liver disease (NAFLD) prevalence, paralleling a steady increase in cirrhosis of the liver and hepatocellular cancer (HCC) related to NAFLD. Currently, NAFLD (related HCC and cirrhosis) is the second most common cause for liver transplantation (LT) and it is projected to take the top spot in the next 3-5 years. Patients with NAFLD cirrhosis and HCC have a unique set of comorbidities which potentially increases their risk for cardiovascular disease (CVD) and mortality. However, a review of the published data in NAFLD patients who undergo LT, does not paint a clear picture. While CVD is the most common cause of non-graft related mortality over the long-term, the short and intermediate-term survival post LT in NAFLD cirrhosis appears to be on par with other etiologies when age and comorbidities are factored. The cardiovascular complications are increased in the immediate post-transplant period but there is a shift from ischemic complications to arrhythmias and heart failure (HF). NAFLD recurs in 80-100% patients and occurs de novo in about 50% after LT, potentially impacting their long-term morbidity and mortality. This review summarizes the available data on CVD in NAFLD patients before and after LT, explains what is currently known about the epidemiology and pathogenesis of CVD in NAFLD and posits strategies to improve wait-list and post-transplant survival.

Impact of preexisting type 2 diabetes mellitus and antidiabetic drugs on all-cause and cause-specific mortality among Medicaid-insured women diagnosed with breast cancer

BACKGROUND

We investigated the influence preexisting type 2 diabetes mellitus (T2DM) and antidiabetic drugs have on all-cause and cause-specific mortality among Medicaid-insured women diagnosed with breast cancer.

METHODS

9221 women aged <64 years diagnosed with breast cancer and reported to the New York State (NYS) Cancer Registry from 2004 to 2016 were linked with Medicaid claims. Preexisting T2DM was determined by three diagnosis claims for T2DM with at least one claim prior to breast cancer diagnosis and a prescription claim for an antidiabetic drug within three months following breast cancer diagnosis. Estimated menopausal status was determined by age (premenopausal age <50; postmenopausal age ≥50). Hazard ratios (HR) and 95 % confidence intervals (95 %CI) were calculated with Cox proportional hazards regression, adjusting for confounders.

RESULTS

Women with preexisting T2DM had greater all-cause (HR = 1.40; 95 %CI 1.21, 1.63), cancer-specific (HR = 1.24; 95 %CI 1.04, 1.47), and cardiovascular-specific (HR = 2.46; 95 %CI 1.54, 3.90) mortality hazard compared to nondiabetic women. In subgroup analyses, the association between T2DM and all-cause mortality was found among non-Hispanic White (HR 1.78 95 %CI 1.38, 2.30) and postmenopausal (HR = 1.47; 95 %CI 1.23, 1.77) women, but not among other race/ethnicity groups or premenopausal women. Additionally, compared to women prescribed metformin, all-cause mortality hazard was elevated among women prescribed sulfonylurea (HR = 1.44; 95 %CI 1.06, 1.94) or insulin (HR = 1.54; 95 %CI 1.12, 2.11).

CONCLUSION

Among Medicaid-insured women with breast cancer, those with preexisting T2DM have an increased mortality hazard, especially when prescribed sulfonylurea or insulin. Further research is warranted to determine the role antidiabetic drugs have on survival among women with breast cancer.

Comparison of primary versus secondary prevention of cardiovascular disease in patients with type2 diabetes: Focus on achievement of ABC goals

BACKGROUND

Primary and secondary prevention of cardiovascular disease is of utmost importance in the management of patients with diabetes.

OBJECTIVES

We studied a group of Iranian patients with type2 diabetes to provide an overview of the current status of secondary prevention of cardiovascular disease in the Middle East.

METHODS

This is a cross-sectional study of 2029 Patients with type2 diabetes including 323 patients with coronary artery disease (CAD) were recruited. Achievement of goals in HbA1c (A), blood pressure (B) and LDL-cholesterol(C) was assessed.

RESULTS

The study showed 25.3% of CAD positive patients achieved HbA1c <7% compared to 30% in CAD negative patients. The achievement of blood pressure ≤140/90 mmHg was 53.2% and 52.8% in CAD positive and CAD negative patients respectively. There was no difference in the achievement of all three ABC goals between the two groups (p = 0.733). After logistic regression analysis, history of hypertension had the highest odds ratio for CAD.

CONCLUSION

Although ABC control has an important impact on the prevention of cardiovascular outcomes, the ideal goal needs further efforts to be achieved.

Atherosclerosis is a vascular stem cell disease caused by insulin

The present article proposes the hypothesis that when multipotent vascular stem cells are exposed to excessive insulin in a rhythmic pattern of sharply rising and falling concentrations, their differentiation is misdirected toward adipogenic and osteogenic cell lineages. This results in plaque-like accumulation of adipocytes with fat and cholesterol deposition from adipocyte debris, and osteogenic (progenitor) cells with a calcified matrix in advanced lesions. The ingrowth of capillaries and infiltration with macrophages, which upon uptake of lipids turn into foam cells, are unspecific pro-resolving reactions. Epidemiological, histopathological, pharmacological, and experimental evidence in favour of this hypothesis is summarised.

Randomized Trial of the Effects of Insulin and Metformin on Myocardial Injury and Stress in Diabetes Mellitus: A Post Hoc Exploratory Analysis

Background

Subclinical myocardial injury, as measured by high‐sensitivity cardiac troponin T (hsTnT), and myocardial stress, as measured by N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP), are related to glycemic control in patients with type 2 diabetes mellitus, and are strong predictors of adverse cardiovascular outcomes. We sought to determine whether antihyperglycemic therapy improves measures of myocardial injury and myocardial stress in patients with type 2 diabetes mellitus.

Methods and Results

We randomized, in a 2×2 factorial fashion, 438 patients with type 2 diabetes mellitus to insulin glargine, metformin, the combination, or placebo and measured changes in NT‐proBNP and hsTnT after 12 weeks of therapy. At baseline, the median (Q1–Q3) plasma concentration was 35.4 (15.7–86.3) ng/L for NT‐proBNP and 6.7 (4.6–10.1) ng/L for hsTnT. The adjusted (95% confidence interval) change in NT‐proBNP concentration was 20.7% (7.9–35.0) in the insulin arm compared with 0.13% (−10.8 to 12.5) in the no‐insulin arm (P=0.03 for comparison). These changes were not related to changes in fasting or postprandial glucose, glycated hemoglobin, weight, blood pressure, or inflammation. In the metformin arm, the adjusted change in NT‐proBNP was 7.8% (−3.7 to 20.7) compared with 13.0% (0.72–26.8) in the no‐metformin arm (P=0.58). No significant changes in hsTnT concentrations were observed for any of the treatment arms.

Conclusions

Insulin glargine was associated with a significant 20.7% increase in NT‐proBNP, a marker of myocardial stress, after 12 weeks of therapy. No change in hsTnT, a marker of myocardial injury, was observed. The changes were independent of substantial improvements in glucose control.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00366301.

Relationship between diabetes and ischaemic injury among patients with revascularized ST-elevation myocardial infarction

AIMS

Studies comparing reperfusion efficacy and myocardial damage between diabetic and non-diabetic patients with ST-elevation myocardial infarction (STEMI) are scarce and have reported conflicting results. The aim was to investigate the impact of preadmission diabetic status on myocardial salvage and damage as determined by cardiac magnetic resonance (CMR), and to evaluate its prognostic relevance.

MATERIALS AND METHODS

We enrolled 792 patients with STEMI at 8 sites. CMR core laboratory analysis was performed to determine infarct characteristics. Major adverse cardiac events (MACE), defined as a composite of all-cause death, non-fatal re-infarction and new congestive heart failure, were recorded at 12 months. Patients were categorized according to preexisting diabetes mellitus (DM), and according to insulin-treated DM (ITDM) and non-insulin-treated DM (NITDM).

RESULTS

One-hundred and sixty (20%) patients had DM and 74 (9%) were insulin-treated. There was no difference in the myocardial salvage index, infarct size, microvascular obstruction and left ventricular ejection fraction between all patient groups (all P > .05). Patients with DM were at higher risk of MACE (11% vs 6%, P = .03) than non-DM patients. After stratification according to preadmission anti-diabetic therapy, MACE rate was comparable between NITDM and non-DM (P > .05), whereas the group of ITDM patients had significantly worse outcome (P < .001).

CONCLUSIONS

Diabetic patients with STEMI, especially those having ITDM, had an increased risk of MACE. The adverse clinical outcome was, however, not explained by an impact of DM on reperfusion success or myocardial damage. Clinical trial registry number: NCT00712101.

The shifting paradigm in the treatment of type 2 diabetes mellitus-A cardiologist's perspective

In patients with diabetes mellitus, cardiovascular (CV) disease is the leading cause of morbidity and mortality. A multitude of contemporary antidiabetic agents presents different CV safety profiles. Metformin forms the cornerstone agent to reduce CV events. Newer agents, such as glucagon-like peptide-1 agonists and sodium-glucose cotransporter-2 inhibitors, have appealing CV benefits. Insulin, dipeptidyl peptidase-4 inhibitors, and sulfonylureas have neutral CV effects. Cardiologists should familiarize themselves with these agents to promote comprehensive CV care in patients with diabetes mellitus.

Increased mortality risk in diabetic patients discharged from hospital with insulin therapy after an acute myocardial infarction: Data from the FAST-MI 2005 registry

BACKGROUND

Merits of insulin use for diabetes treatment in patients with advanced atherosclerosis are debated. This observational study conducted in diabetic patients after an acute myocardial infarction aimed to assess whether insulin prescription at discharge (IPD) was related to all-cause mortality during follow-up.

METHODS

Subjects were diabetic patients admitted in intensive- or coronary-care units for acute myocardial infarction (consecutively recruited in 223 centres in France) and discharged alive from the hospital, with or without an IPD. Vital status after five years was obtained and the relationship between insulin prescription at discharge and survival was studied.

RESULTS

Overall, 1221 diabetic patients were discharged alive and 38% had an IPD. Factors independently related to IPD were female gender, hospitalization in a public hospital, duration of diabetes, HbA1c level, smoking, peripheral artery disease, history of coronary heart disease and Killip class. After adjustment, IPD was independently related to all-cause mortality after five years of follow-up (adjusted hazard ratio = 1.72 (1.42-2.09), p<0.001). This increased mortality in subjects with IPD was also observed in propensity matched analyses, when subjects actually treated or actually not treated with insulin at discharge were compared in two groups matched on their computed probability of having had insulin prescribed.

CONCLUSIONS

Insulin was preferably prescribed in seriously affected patients, regarding diabetes and cardiovascular risk. However, insulin prescription at discharge was associated with increased all-cause mortality after extensive adjustments for confounders. These results suggest possible intrinsic harmful effects of insulin in high-risk diabetic patients after myocardial infarction.

The effects of dual-therapy intensification with insulin or dipeptidylpeptidase-4 inhibitor on cardiovascular events and all-cause mortality in patients with type 2 diabetes: A retrospective cohort study

PURPOSE

To compare time to a composite endpoint of non-fatal acute myocardial infarction, non-fatal stroke or all-cause mortality in patients with type 2 diabetes mellitus who had their treatment intensified with a dipeptidylpeptidase-4 inhibitor or insulin following dual-therapy (metformin plus sulfonylurea) failure.

METHODS

A retrospective cohort study was conducted on 5238 patients newly treated with either a dipeptidylpeptidase-4 inhibitor or insulin following dual-therapy failure (2007-2014). Data were sourced from UK General Practices. The risk of the composite outcome was compared between two treatment groups: metformin + sulfonylurea + insulin ( n = 1584) and metformin + sulfonylurea + dipeptidylpeptidase-4 inhibitor ( n = 3654), while adjusting for baseline covariates. Follow-up was for up to 5 years. Propensity score matching analysis and Cox proportional hazard models were employed.

RESULTS

Overall, 123 and 171 composite outcome events occurred among patients who added insulin versus dipeptidylpeptidase-4 inhibitor, respectively (44.5 vs 14.6 events per 1000 person-years). Addition of insulin was associated with a significantly higher hazard ratio versus the addition of a dipeptidylpeptidase-4 inhibitor (adjusted hazard ratio = 2.6, 95% confidence interval: 1.9-3.4; p < 0.01), an effect that was more pronounced in obese (body mass index: 30-34.9 kg/m²) patients (corresponding adjusted hazard ratio 3.6, 95% confidence interval: 2.3-5.6; p < 0.01).

CONCLUSION

In routine clinical practice, intensification of metformin + sulfonylurea therapy by adding insulin is associated with increased risk of cardiovascular events and death compared with adding a dipeptidylpeptidase-4 inhibitor. These findings are in line with suggestions from previous studies regarding the cardiovascular safety of insulin in type 2 diabetes mellitus, but should be interpreted with caution.

Be Careful What You Ask For: Effects of Benefit Descriptions on Diabetes Patients' Benefit-Risk Tradeoff Preferences

BACKGROUND

As more studies report on patient preferences for diabetes treatment, identifying diabetes outcomes other than glycated hemoglobin (HbA_1c) to describe effectiveness is warranted to understand patient-relevant, benefit-risk tradeoffs.

OBJECTIVE

The aim of the study was to evaluate how preferences differ when effectiveness (glycemic control) is presented as long-term sequela (LTS) risk mitigation rather than an asymptomatic technical marker (HbA_1c).

METHODS

People with type 2 diabetes and using insulin (n = 3160) were randomly assigned to four self-administered, discrete-choice experiments that differed by their presentation of effectiveness. Epidemiologic reviews were conducted to ensure a close approximation of LTS risk relative to HbA_1c levels. The relative importance of treatment benefit-risk characteristics and maximum acceptable risk tradeoffs was estimated using an error-component logit model. Log-likelihood ratio tests were used to compare parameter vectors.

RESULTS

In total, 1031 people responded to the survey. Significantly more severe hypoglycemic events were accepted for a health improvement in terms of LTS mitigation versus HbA_1c improvement (0.7 events per year; 95% confidence interval [CI]: 0.4-1.0 vs. 0.2 events per year 95% CI: -0.02 to 0.5) and avoidance of treatment-related heart attack risk (1.4 severe hypoglycemic events per year; 95% CI: 0.8-1.9 vs. 1 event per year; 95% CI: 0.6-1.3). This finding is supported by a log-likelihood test that rejected at the 0.05 level that respondent preference structures are similar across the different experimental arms of the discrete-choice experiment.

CONCLUSION

We found evidence that benefit descriptions influence elicited preferences for the benefit-risk characteristics of injectable diabetes treatment. These findings argue for using carefully defined effectiveness measures to accurately take account of the patient perspective in benefit-risk assessments.

Comparison of cardiovascular and metabolic outcomes in people with type 2 diabetes on insulin versus non-insulin glucose-lowering therapies (GLTs): A systematic review and meta-analysis of clinical trials

OBJECTIVES

To compare the cardiovascular and metabolic outcomes of Insulin versus non-insulin glucose lowering therapy (GLT).

METHODS

We included randomised control trials (RCTs) which randomised patients aged >18years with Type 2 Diabetes (T2D) to insulin vs non-insulin GLT. We used risk ratios (RR), risk difference (RD) and odds ratios (OR) with 95% confidence interval (95%CI) to analyse the treatment effects of dichotomous outcomes and mean differences (with 95% CI) for continuous outcomes.

RESULTS

We included 18 RCTs with 19,300 participants. There was no significant difference in the risk of all-cause mortality and CV events between the groups (RR=1.01; 95%CI: 0.96-1.06; p=0.69). In 16 trials, insulin showed greater efficacy in glycaemic control (mean diff=-0.20; 95%CI: -0.28 to -0.11) but the proportion achieving HbA1c level of either ⩽7.0% or 7.4% (53 or 57mmol/mol) was similar in both (OR=1.55; 95%CI=0.92-2.62). The non-insulin group had a significant reduction in weight (mean diff=-3.41; 95%CI: -4.50 to -2.32) and an increase in the proportion of adverse events (54.7% vs 45.3%, p=0.044), but the insulin group showed an (RR=1.90; 95%CI: 1.44-2.51) increased risk of hypoglycaemia.

CONCLUSION

There was no difference in the risk of all-cause mortality and adverse cardiovascular (CV) events between Insulin and non-insulin GLTs. Insulin was associated with superior reduction in HbA1c; least reduction in weight and higher risk of hypoglycaemia. Both showed similar proportion of patients achieving HbA1c target. Non-insulin GLTs were associated with a higher risk in reported adverse drug events.

Efficacy and safety of insulin in type 2 diabetes: meta-analysis of randomised controlled trials

BACKGROUND

It is essential to anticipate and limit the social, economic and sanitary cost of type 2 diabetes (T2D), which is in constant progression worldwide. When blood glucose targets are not achieved with diet and lifestyle intervention, insulin is recommended whether or not the patient is already taking hypoglycaemic drugs. However, the benefit/risk balance of insulin remains controversial. Our aim was to determine the efficacy and safety of insulin vs. hypoglycaemic drugs or diet/placebo on clinically relevant endpoints.

METHODS

A systematic literature review (Pubmed, Embase, Cochrane Library) including all randomised clinical trials (RCT) analysing insulin vs. hypoglycaemic drugs or diet/placebo, published between 1950 and 2013, was performed. We included all RCTs reporting effects on all-cause mortality, cardiovascular mortality, death by cancer, cardiovascular morbidity, microvascular complications and hypoglycaemia in adults ≥ 18 years with T2D. Two authors independently assessed trial eligibility and extracted the data. Internal validity of studies was analyzed according to the Cochrane Risk of Bias tool. Risk ratios (RR) with 95 % confidence intervals (95 % CI) were calculated, using the fixed effect model in first approach. The I(2) statistic assessed heterogeneity. In case of statistical heterogeneity, subgroup and sensitivity analyses then a random effect model were performed. The alpha threshold was 0.05. Primary outcomes were all-cause mortality and cardiovascular mortality. Secondary outcomes were non-fatal cardiovascular events, hypoglycaemic events, death from cancer, and macro- or microvascular complications.

RESULTS

Twenty RCTs were included out of the 1632 initially identified studies. 18 599 patients were analysed: Insulin had no effect vs. hypoglycaemic drugs on all-cause mortality RR = 0.99 (95 % CI =0.92-1.06) and cardiovascular mortality RR = 0.99 (95 % CI =0.90-1.09), nor vs. diet/placebo RR = 0.92 (95 % CI = 0.80-1.07) and RR = 0.95 (95 % CI 0.77-1.18) respectively. No effect was found on secondary outcomes either. However, severe hypoglycaemia was more frequent with insulin compared to hypoglycaemic drugs RR = 1.70 (95 % CI = 1.51-1.91).

CONCLUSIONS

There is no significant evidence of long term efficacy of insulin on any clinical outcome in T2D. However, there is a trend to clinically harmful adverse effects such as hypoglycaemia and weight gain. The only benefit could be limited to reducing short term hyperglycemia. This needs to be confirmed with further studies.

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.

Insulin Dose and Cardiovascular Mortality in the ACCORD Trial

OBJECTIVE

In the ACCORD trial, intensive treatment of patients with type 2 diabetes and high cardiovascular (CV) risk was associated with higher all-cause and CV mortality. Post hoc analyses have failed to implicate rapid reduction of glucose, hypoglycemia, or specific drugs as the causes of this finding. We hypothesized that exposure to injected insulin was quantitatively associated with increased CV mortality.

RESEARCH DESIGN AND METHODS

We examined insulin exposure data from 10,163 participants with a mean follow-up of 5 years. Using Cox proportional hazards models, we explored associations between CV mortality and total, basal, and prandial insulin dose over time, adjusting for both baseline and on-treatment covariates including randomized intervention assignment.

RESULTS

More participants allocated to intensive treatment (79%) than standard treatment (62%) were ever prescribed insulin in ACCORD, with a higher mean updated total daily dose (0.41 vs. 0.30 units/kg) (P < 0.001). Before adjustment for covariates, higher insulin dose was associated with increased risk of CV death (hazard ratios [HRs] per 1 unit/kg/day 1.83 [1.45, 2.31], 2.29 [1.62, 3.23], and 3.36 [2.00, 5.66] for total, basal, and prandial insulin, respectively). However, after adjustment for baseline covariates, no significant association of insulin dose with CV death remained. Moreover, further adjustment for severe hypoglycemia, weight change, attained A1C, and randomized treatment assignment did not materially alter this observation.

CONCLUSIONS

These analyses provide no support for the hypothesis that insulin dose contributed to CV mortality in ACCORD.

Impact of glucose-lowering drugs on cardiovascular disease in type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by multiple pathophysiologic abnormalities. With time, multiple glucose-lowering medications are commonly required to reduce and maintain plasma glucose concentrations within the normal range. Type 2 diabetes mellitus individuals also are at a very high risk for microvascular complications and the incidence of heart attack and stroke is increased two- to three-fold compared with non-diabetic individuals. Therefore, when selecting medications to normalize glucose levels in T2DM patients, it is important that the agent not aggravate, and ideally even improve, cardiovascular risk factors (CVRFs) and reduce cardiovascular morbidity and mortality. In this review, we examine the effect of oral (metformin, sulfonylureas, meglitinides, thiazolidinediones, DPP4 inhibitors, SGLT2 inhibitors, and α-glucosidase inhibitors) and injectable (glucagon-like peptide-1 receptor agonists and insulin) glucose-lowering drugs on established CVRFs and long-term studies of cardiovascular outcomes. Firm evidence that in T2DM cardiovascular disease can be reversed or prevented by improving glycaemic control is still incomplete and must await large, long-term clinical trials in patients at low risk using modern treatment strategies, i.e., drug combinations designed to maximize HbA1c reduction while minimizing hypoglycaemia and excessive weight gain.

Comparative cardiovascular morbidity and mortality in patients taking different insulin regimens for type 2 diabetes: a systematic review

OBJECTIVES

To summarise the literature evaluating the association between different insulin regimens and the incidence of cardiovascular morbidity and mortality in adults with type 2 diabetes.

DESIGN

Systematic review.

METHODS

Multiple biomedical databases (The Cochrane Library, PubMed, EMBASE, and International Pharmaceutical Abstracts) were searched from their inception to February 2014. References of included studies were hand searched. Randomised controlled trials (RCTs), cohort studies or case-control studies examining adults (≥18 years) with type 2 diabetes taking any type, dose and/or regimen of insulin were eligible for inclusion in this review.

OUTCOME MEASURES

Primary outcomes were cardiovascular morbidity and mortality including fatal and/or non-fatal myocardial infarction, fatal and/or non-fatal stroke, major adverse cardiac events and cardiovascular death. All-cause mortality was assessed as a secondary outcome.

RESULTS

Of the 3122 studies identified, 2 RCTs and 6 cohort studies were selected. No case-control studies met the inclusion criteria. The studies examined a total of 109,910 patients. Quantitative synthesis of the results from included studies was not possible due to a large amount of clinical heterogeneity. Each study evaluated cardiovascular outcomes across different insulin-exposure contrasts. RCTs did not identify any difference in cardiovascular risks among a fixed versus variable insulin regimen, or a prandial versus basal regimen, albeit clinically important risks and benefits cannot be ruled out due to wide CIs. Findings from cohort studies were variable with an increased and decreased risk of cardiovascular events and all-cause mortality being reported.

CONCLUSIONS

This systematic review of randomised and non-randomised studies identifies a substantive gap in the literature surrounding the cardiovascular morbidity and mortality of patients using different regimens of insulin. There is a need for more consistent high-quality evidence investigating the impact of insulin use on cardiovascular outcomes in patients with type 2 diabetes.

TRIAL REGISTRATION NUMBER

PROSPERO

CRD42014007631.

Long-term mortality after primary percutaneous coronary intervention for ST-segment elevation myocardial infarction in patients with insulin-treated versus non-insulin-treated diabetes mellitus

AIMS

We investigated the impact of preadmission diabetic status on long-term outcome in patients with ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI), to improve risk stratification.

METHODS AND RESULTS

Between 1997 and 2007, 4,402 STEMI patients were admitted to our hospital and stratified as having insulin-treated diabetes mellitus (ITDM) (n=176), non-ITDM (NITDM) (n=354) and non-DM (n=3,872). Five-year mortality was significantly higher in patients with DM compared to non-DM (29% vs. 18%, p<0.01). After stratification for preadmission glucose-lowering therapy, five-year mortality was significantly higher in ITDM patients compared to NITDM (36% vs. 25%, p=0.01) and in NITDM patients compared to non-DM patients (25% vs. 18%, p<0.01). After adjustment for age and gender the mortality risk between patients with NITDM versus non-DM was comparable (HR: 1.1, 95% CI: 0.9-1.4, p=0.38), in contrast to patients with ITDM (HR: 1.9, 95% CI: 1.5-2.5, p<0.01) and ITDM versus NITDM (HR: 1.7, 95% CI: 1.2-2.4, p<0.01). After adjustment for all baseline characteristics, the results were comparable to the age and gender adjusted model.

CONCLUSIONS

ITDM was a strong predictor for long-term mortality when compared to non-DM and NITDM. The mortality between patients without DM and NITDM was comparable after adjustment for age and gender.

Is incretin-based therapy ready for the care of hospitalized patients with type 2 diabetes?: The time has come for GLP-1 receptor agonists!

Significant data suggest that overt hyperglycemia, either observed with or without a prior diagnosis of diabetes, contributes to an increase in mortality and morbidity in hospitalized patients. In this regard, goal-directed insulin therapy has remained as the standard of care for achieving and maintaining glycemic control in hospitalized patients with critical and noncritical illness. As such, protocols to assist in the management of hyperglycemia in the inpatient setting have become commonplace in hospital settings. Clearly, insulin is a known entity, has been in clinical use for almost a century, and is effective. However, there are limitations to its use. Based on the observed mechanisms of action and efficacy, there has been a great interest in using incretin-based therapy with glucagon-like peptide-1 (GLP-1) receptor agonists instead of, or complementary to, an insulin-based approach to improve glycemic control in hospitalized, severely ill diabetic patients. To provide an understanding of both sides of the argument, we provide a discussion of this topic as part of this two-part point-counterpoint narrative. In this point narrative as presented below, Drs. Schwartz and DeFronzo provide an opinion that now is the time to consider GLP-1 receptor agonists as a logical consideration for inpatient glycemic control. It is important to note the recommendations they propose under "incretin-based approach" with these agents represent their opinion for use and, as they point out, well-designed prospective studies comparing these agents with insulin will be required to establish their efficacy and safety. In the counterpoint narrative following Drs. Schwartz and DeFronzo's contribution, Drs. Umpierrez and Korytkowski provide a defense of insulin in the inpatient setting as the unquestioned gold standard for glycemic management in hospitalized settings.

Beneficial and detrimental effects of glycemic control on cardiovascular disease in type 2 diabetes

Epidemiological data demonstrates that improved regulation of blood glucose correlates with better cardiovascular (CV) outcomes. Conversely, some interventional studies have demonstrated that tight glycemic control has no benefit or can even result in worse CV outcomes. These conclusions parallel the paradox that glycemic control has proven beneficial for microvascular outcomes, while few studies have demonstrated significant macrovascular benefits. This imprecise understanding conveys the need to better comprehend the mechanisms of glycemic control and its impact on CV disease. Such variations in data also require a more comprehensive approach to diabetes and CV disease in which multiple biomarkers such as low density lipoprotein (LDL), low adiponectin, elevated C-reactive protein (CRP) and well established clinical parameters such as high blood pressure, weight, and functional status are incorporated into clinical decision making. Reliance on one parameter in isolation such as glycemic control and one biomarker such as HbA1C does not provide an accurate assessment of CV outcomes.

Insulin and atherosclerosis: how are they related?

The relationship between insulin and atherosclerosis is complex. People with type 2 diabetes are affected by three main glycaemic disorders: chronic hyperglycaemia; glycaemic variability; and iatrogenic hypoglycaemia. In addition to this triumvirate, the diabetic condition is characterized by lipid disorders, chronic low-grade inflammation and activation of oxidative stress. All these associated disorders reflect the insulin-resistant nature of type 2 diabetes and contribute to the development and progression of cardiovascular (CV) diseases. By both lowering plasma glucose and improving the lipid profile, insulin exerts beneficial effects on CV outcomes. In addition, insulin has several pleiotropic effects such as anti-inflammatory, antithrombotic and antioxidant properties. Insulin per se exerts an inhibitory effect on the activation of oxidative stress and seems able to counteract the pro-oxidant effects of ambient hyperglycaemia and glycaemic variability. However, insulin actions remain a subject of debate with respect to the risk of adverse CV events, which can increase in individuals exposed to high insulin doses. Evidence from the large-scale, long-term ORIGIN trial suggests that early implementation of insulin supplementation therapy in the course of glycaemic disorders, including type 2 diabetes, has a neutral impact on CV outcomes compared with standard management. Thus, the answer to the question "What impact does insulin have on atherosclerosis?" remains unclear, even though it is logical to deduce that insulin should be initiated as soon as possible and that small doses of insulin early on are better than higher doses later in the disease process.

Mortality and other important diabetes-related outcomes with insulin vs other antihyperglycemic therapies in type 2 diabetes

CONTEXT

The safety of insulin in the treatment of type 2 diabetes mellitus (T2DM) has recently undergone scrutiny.

OBJECTIVE

The objective of the study was to characterize the risk of adverse events associated with glucose-lowering therapies in people with T2DM.

DESIGN AND SETTING

This was a retrospective cohort study using data from the UK General Practice Research Database, 2000-2010.

PATIENTS

Patients comprised 84 622 primary care patients with T2DM treated with one of five glucose-lowering regimens: metformin monotherapy, sulfonylurea monotherapy, insulin monotherapy, metformin plus sulfonylurea combination therapy, and insulin plus metformin combination therapy. There were 105 123 exposure periods.

MAIN OUTCOME MEASURES

The risk of the first major adverse cardiac event, first cancer, or mortality was measured. Secondary outcomes included these individual constituents and microvascular complications.

RESULTS

In the same model, and using metformin monotherapy as the referent, the adjusted hazard ratio (aHR) for the primary end point was significantly increased for sulfonylurea monotherapy (1.436, 95% confidence interval [CI] 1.354-1.523), insulin monotherapy (1.808, 95% CI 1.630-2.005), and insulin plus metformin (1.309, 95% CI 1.150-1.491). In glycosylated hemoglobin/morbidity subgroups, patients treated with insulin monotherapy had aHRs for the primary outcome ranging from 1.469 (95% CI 0.978-2.206) to 2.644 (95% CI 1.896-3.687). For all secondary outcomes, insulin monotherapy had increased aHRs: myocardial infarction (1.954, 95% CI 1.479-2.583), major adverse cardiac events (1.736, 95% CI 1.441-2.092), stroke (1.432, 95% CI 1.159-1.771), renal complications (3.504, 95% CI 2.718-4.518), neuropathy (2.146, 95% CI 1.832-2.514), eye complications (1.171, 95% CI 1.057-1.298), cancer (1.437, 95% CI 1.234-1.674), or all-cause mortality (2.197, 95% CI 1.983-2.434). When compared directly, aHRs were higher for insulin monotherapy vs all other regimens for the primary end point and all-cause mortality.

CONCLUSIONS

In people with T2DM, exogenous insulin therapy was associated with an increased risk of diabetes-related complications, cancer, and all-cause mortality. Differences in baseline characteristics between treatment groups should be considered when interpreting these results.

The safety profile of exogenous insulin in people with type 2 diabetes: justification for concern

There is no doubt about the value of exogenous insulin for people with type 1 diabetes. The purpose of this commentary is to discuss emerging evidence that this may not be the case for the majority of people with type 2 diabetes.

Evaluation of the incremental cost to the National Health Service of prescribing analogue insulin

Introduction Insulin analogues have become increasingly popular despite their greater cost compared with human insulin. The aim of this study was to calculate the incremental cost to the National Health Service (NHS) of prescribing analogue insulin preparations instead of their human insulin alternatives. Methods Open-source data from the four UK prescription pricing agencies from 2000 to 2009 were analysed. Cost was adjusted for inflation and reported in UK pounds at 2010 prices. Results Over the 10-year period, the NHS spent a total of £2732 million on insulin. The total annual cost increased from £156 million to £359 million, an increase of 130%. The annual cost of analogue insulin increased from £18.2 million (12% of total insulin cost) to £305 million (85% of total insulin cost), whereas the cost of human insulin decreased from £131 million (84% of total insulin cost) to £51 million (14% of total insulin cost). If it is assumed that all patients using insulin analogues could have received human insulin instead, the overall incremental cost of analogue insulin was £625 million. Conclusion Given the high marginal cost of analogue insulin, adherence to prescribing guidelines recommending the preferential use of human insulin would have resulted in considerable financial savings over the period.