Recent HbA1c values and mortality risk in type 2 diabetes. population-based case-control study
Jennifer Nicholas1, Judith Charlton, Alex Dregan
1London School of Hygiene and Tropical Medicine, Department of Medical Statistics, London, United Kingdom.
Plos One
|July 18, 2013
Summary
Extreme HbA1c levels (<6.5% or >9.0%) in type 2 diabetes are linked to higher one-year mortality risk. This risk is notably greater for younger patients with type 2 diabetes.
Area of Science:
- Endocrinology
- Diabetes Mellitus Research
- Clinical Epidemiology
Background:
- Type 2 diabetes mellitus (T2DM) management often involves glycemic control targets.
- Hemoglobin A1c (HbA1c) is a key marker for long-term glycemic control.
- The mortality risk associated with extreme HbA1c values in T2DM requires further investigation.
Purpose of the Study:
- To evaluate the association between HbA1c levels below 6.5% or above 9.0% and 365-day mortality in patients with T2DM.
- To assess how this association varies with age.
Main Methods:
- A matched nested case-control study design was employed within a large cohort of T2DM patients (2000-2008).
- Conditional logistic regression was used to calculate adjusted odds ratios (AOR) for mortality.
- Comorbidity and drug utilization were adjusted for in the analysis.
Main Results:
- Both HbA1c <6.5% (AOR 1.20) and HbA1c >9.0% (AOR 1.29) were associated with increased 1-year mortality after multiple imputation.
- The association between HbA1c <6.5% and mortality was age-dependent, with higher risk in younger individuals (AOR 1.53 for age <55).
- The risk diminished with increasing age, becoming non-significant in older age groups (AOR 1.04 for age 85+).
Conclusions:
- In clinical T2DM, HbA1c values outside the target range (<6.5% or >9.0%) may be linked to elevated short-term mortality.
- The increased mortality risk associated with very low HbA1c levels appears more pronounced in younger T2DM patients.
- These findings highlight the potential risks of both hyperglycemia and hypoglycemia in T2DM management.
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