New England Journal of Medicine JULY 26, 2012

Basal Insulin and Cardiovascular and Other Outcomes in Dysglycemia

The ORIGIN Trial Investigators

Bottom Line

The ORIGIN trial demonstrated that basal insulin glargine, titrated to normalize fasting plasma glucose, did not reduce cardiovascular outcomes or mortality compared to standard care in high-risk patients with dysglycemia, although it did reduce the progression to new-onset diabetes.

Key Findings

1. Insulin glargine had a neutral effect on the first co-primary endpoint (cardiovascular death, myocardial infarction, or stroke), occurring in 26.7% of the glargine group versus 27.5% of the standard care group (hazard ratio 1.02; 95% CI 0.94–1.11; P=0.63).

2. The second co-primary endpoint (cardiovascular death, myocardial infarction, stroke, revascularization, or hospitalization for heart failure) also showed no significant difference (31.4% vs. 32.1%; hazard ratio 1.04; 95% CI 0.97–1.11; P=0.27).

3. Among patients without diabetes at baseline, insulin glargine significantly reduced the risk of new-onset diabetes compared to standard care (25% vs. 31%; hazard ratio 0.72; 95% CI 0.58–0.90; P=0.006).

4. Severe hypoglycemia was significantly more frequent with insulin glargine (1.00 per 100 person-years) compared to standard care (0.31 per 100 person-years; P<0.001).

5. Treatment with insulin glargine was associated with a modest weight gain (median 1.6 kg) compared to weight loss in the standard care group (median 0.5 kg).

Study Design

Design

RCT

Open-Label

Sample

12,537

Patients

Duration

6.2 yr

Median

Setting

40 countries

Population Patients at least 50 years of age with impaired fasting glucose, impaired glucose tolerance, or early type 2 diabetes, and established cardiovascular risk factors.

Intervention Basal insulin glargine titrated to target a fasting plasma glucose level of 95 mg/dL (5.3 mmol/L) or lower.

Comparator Standard care not utilizing basal insulin.

Outcome Co-primary endpoints were: 1) the composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke; and 2) the composite of cardiovascular death, nonfatal myocardial infarction, nonfatal stroke, revascularization, or hospitalization for heart failure.

Study Limitations

• The trial was conducted in a specific high-risk population, limiting the generalizability of these findings to lower-risk individuals with dysglycemia.

• The open-label nature of the insulin administration could potentially introduce bias, though this was mitigated by centralized, blinded endpoint adjudication.

• The relatively high background usage of other glucose-lowering medications and cardiovascular therapies may have masked potential smaller benefits of intensive insulin therapy.

Clinical Significance

The results suggest that while achieving normoglycemia with basal insulin provides excellent glycemic control and reduces the incidence of new diabetes in high-risk patients, it does not confer additional cardiovascular benefit or mortality reduction. Clinicians should weigh the glycemic improvements against the increased risk of hypoglycemia and weight gain when considering insulin initiation in this population.

Historical Context

At the time of the trial, there was significant debate regarding whether aggressive glycemic control, particularly with insulin, could reduce cardiovascular complications in patients with early dysglycemia. The ORIGIN trial was designed to formally test this hypothesis, providing high-level evidence that remains a cornerstone in modern diabetes management guidelines regarding the use of basal insulin.

Guided Discussion

High-yield insights from every perspective

Med Student

Medical Student

What is the physiological rationale behind the 'beta-cell rest' hypothesis in early dysglycemia, and how did the ORIGIN trial test this through the use of insulin glargine?

Key Response

The 'beta-cell rest' hypothesis suggests that providing exogenous insulin early in the course of dysglycemia (prediabetes or early T2DM) can reduce the secretory burden on pancreatic beta-cells, potentially preserving their function and slowing disease progression. The ORIGIN trial tested this by titrating insulin glargine to normalize fasting plasma glucose levels (target <95 mg/dL) and demonstrated a 28% reduction in the progression from prediabetes to new-onset type 2 diabetes.

Resident

A patient with pre-diabetes and high cardiovascular risk asks if starting insulin early will prevent a heart attack. Based on the ORIGIN trial, how should you counsel them regarding the cardiovascular benefits and risks of early basal insulin therapy?

Key Response

Counsel the patient that according to the ORIGIN trial, early use of insulin glargine does not reduce the risk of major adverse cardiovascular events (MI, stroke, or CV death) compared to standard care. Furthermore, insulin use is associated with a modest weight gain (mean 1.6 kg) and a significantly higher risk of hypoglycemia (severe episodes: 1.00 vs. 0.31 per 100 person-years), though the absolute risk of severe hypoglycemia remains low.

Fellow

Compare the findings of the ORIGIN trial with the results of the ACCORD trial regarding 'metabolic neutrality' and cardiovascular safety. What does ORIGIN tell us about the safety of targeting near-normoglycemia using basal insulin?

Key Response

Unlike the ACCORD trial, which showed increased mortality with an intensive glucose-lowering strategy (targeting HbA1c <6.0%), the ORIGIN trial demonstrated 'metabolic neutrality.' It proved that achieving near-normal fasting glucose levels using insulin glargine over a median follow-up of 6.2 years is cardiovascularly safe and does not increase the risk of cancer or mortality, providing reassurance for its long-term use in dysglycemic populations.

Attending

In the context of the shift toward GLP-1 RAs and SGLT2 inhibitors for cardiovascular protection, how does the ORIGIN trial's 'neutral' result for insulin glargine influence the contemporary management of high-risk patients who require add-on glycemic control?

Key Response

The ORIGIN trial establishes insulin glargine as a 'cardiovascularly safe' but not 'cardiovascularly protective' agent. In the modern era, where GLP-1 RAs and SGLT2 inhibitors are prioritized for their proven CV benefits in high-risk patients, ORIGIN indicates that glargine remains a reliable tool for achieving glycemic targets without increasing CV risk once the protective agents have been optimized, particularly in those with early dysglycemia where avoiding diabetes progression is a goal.

Scholarly Review

Critical appraisal through the lens of expert reviewers and guideline development

PhD

The ORIGIN trial employed a 2x2 factorial design evaluating insulin glargine and omega-3 fatty acids. What are the specific statistical risks of a factorial design in this context, and how might an interaction between the two interventions influence the interpretation of the primary cardiovascular endpoint?

Key Response

A 2x2 factorial design assumes 'no interaction' between interventions to maintain power. If insulin glargine's metabolic effects were modified by the anti-inflammatory or lipid-lowering effects of omega-3s, the observed effect size for the primary outcome could be diluted. Methodologically, if an interaction exists but is not statistically accounted for, the study may provide an underpowered estimate of each individual intervention’s efficacy, necessitating a formal interaction test (which, in ORIGIN, showed no significant interaction).

Journal Editor

Critically appraise the potential for 'contamination' or 'drop-in' bias in the ORIGIN trial's control group and how this might have impacted the hazard ratio for the primary composite cardiovascular outcome.

Key Response

The control group received 'standard care,' which often included metformin or sulfonylureas. As the trial progressed, many in the control group required intensification of therapy to manage glucose, narrowing the glycemic difference between the two groups (mean HbA1c difference was only 0.3%). This 'contamination' of the control arm with other glucose-lowering agents could lead to a Type II error, potentially masking a small but significant macrovascular benefit that might have been seen in a truly untreated control.

Guideline Committee

Given that ORIGIN showed a reduction in the progression to diabetes but no reduction in CV events, should basal insulin be recommended alongside metformin in the ADA Standards of Care for diabetes prevention in high-risk patients?

Key Response

Current ADA guidelines (referencing ORIGIN and the DPP) prioritize lifestyle and metformin for diabetes prevention. While ORIGIN provided Level 1 evidence that glargine reduces progression to diabetes, the lack of CV benefit combined with the costs, need for injections, and risk of hypoglycemia makes it a secondary consideration. Guidelines currently state it 'may' be considered for glycemic control but do not elevate it to a primary prevention recommendation for CV outcomes in pre-diabetes.

Clinical Landscape

Noteworthy Related Trials

2008

ACCORD Trial

n = 10,251 · NEJM

Tested

Intensive glycemic control (target HbA1c <6.0%)

Population

T2DM patients at high risk for cardiovascular disease

Comparator

Standard glycemic control (target HbA1c 7.0-7.9%)

Endpoint

Major adverse cardiovascular events

Key result: Intensive therapy failed to reduce major cardiovascular events and was associated with increased mortality.

2008

ADVANCE Trial

n = 11,140 · NEJM

Tested

Intensive glucose control (target HbA1c <6.5%)

Population

T2DM patients with at least one vascular disease or risk factor

Comparator

Standard glycemic control

Endpoint

Composite of major macrovascular and microvascular events

Key result: Intensive glucose control significantly reduced the incidence of major microvascular events but did not significantly reduce major macrovascular events or mortality.

2009

VADT

n = 1,791 · NEJM

Tested

Intensive glucose control therapy

Population

T2DM patients with poorly controlled disease and high cardiovascular risk

Comparator

Standard glucose control therapy

Endpoint

Composite of major cardiovascular events

Key result: Intensive glucose control did not significantly reduce the rate of major cardiovascular events or cardiovascular death in patients with long-standing T2DM.

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