The relation between HbA1c and cardiovascular events in patients with type 2 diabetes with and without vascular
Guido Kranenburg1, Yolanda van der Graaf2, Joep van der Leeuw1
1Department of Vascular Medicine, University Medical Centre Utrecht, Utrecht, the Netherlands.
Insights
Poor glycemic control in type 2 diabetes patients showed no significant link to cardiovascular events, regardless of existing vascular disease. This suggests that while HbA1c levels are important, their impact on vascular events may not differ based on prior vascular conditions.
Area of Science:
- Cardiology
- Endocrinology
- Diabetes Research
Background:
- Poor glycemic control, indicated by elevated Hemoglobin A1c (HbA1c) levels, is a known risk factor for vascular events in type 2 diabetes.
- The influence of pre-existing vascular disease on the relationship between glycemic control and cardiovascular outcomes remains unclear.
Purpose of the Study:
- To investigate the association between HbA1c levels and new cardiovascular events and mortality in patients with type 2 diabetes.
- To determine if the presence of vascular disease modifies the relationship between glycemic control and adverse vascular outcomes.
Main Methods:
- A cohort of 1,687 patients with type 2 diabetes from the Second Manifestations of Arterial Disease (SMART) study was analyzed.
- Cox proportional hazard analyses were used to evaluate the continuous relationship between HbA1c and cardiovascular events (myocardial infarction, stroke, vascular mortality) and all-cause mortality.
- Analyses were stratified based on the presence or absence of established vascular disease.
Main Results:
- Over a median follow-up of 6.1 years, 293 patients experienced a new cardiovascular event and 340 died.
- A 1% increase in HbA1c was associated with a 27% higher risk of cardiovascular events in patients without vascular disease (HR 1.27), but not in those with vascular disease (HR 1.03).
- A 1% increase in HbA1c was linked to a 16% higher risk of death in patients with vascular disease (HR 1.16), and a nonsignificant 13% higher risk in those without (HR 1.13).
Conclusions:
- There is a modest, non-statistically significant association between HbA1c levels and cardiovascular events in type 2 diabetes patients.
- The relationship between HbA1c and cardiovascular events did not significantly differ between patients with and without clinical manifestation of vascular disease.
Objective:
Poor glycemic control is related to vascular events in patients with type 2 diabetes, but the presence of vascular disease might influence this relation. We evaluated the relation between glycemic control (HbA1c level) and new cardiovascular events and mortality in patients with type 2 diabetes, with and without vascular disease.
Research Design And Methods:
In a cohort of 1,687 patients with type 2 diabetes enrolled in the Second Manifestations of Arterial Disease (SMART) study, the continuous relation between HbA1c and cardiovascular events (composite of myocardial infarction, stroke, and vascular mortality) and all-cause mortality was evaluated with Cox proportional hazard analyses stratified for the presence of vascular disease.
Results:
During a median follow-up time of 6.1 years (interquartile range 3.1-9.5 years), a new cardiovascular event developed in 293 patients and 340 patients died. In all patients, the hazard ratio (HR) of the relation between HbA1c level and cardiovascular events was 1.06 (95% CI 0.97-1.17). A 1 percentage point higher HbA1c level was related to a 27% higher risk of a cardiovascular event in patients with type 2 diabetes without vascular disease (HR 1.27 [95% CI 1.06-1.51]), but not in patients with vascular disease (HR 1.03 [95% CI 0.93-1.15], P for interaction = 0.195). A 1 percentage point higher HbA1c level was related to a 16% higher risk of death (HR 1.16 [95% CI 1.06-1.28]) in patients with vascular disease and a nonsignificant 13% higher risk of all-cause mortality (HR 1.13 [95% CI 0.97-1.31]) in patients without vascular disease.
Conclusions:
In patients with type 2 diabetes, there is a modest, but not statistically significant, relation between HbA1c level and cardiovascular events, and, as there was no statistically significant interaction, this relation was not different for patients with or without clinical manifestation of vascular disease.
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