High HbA1c levels: dangerous even in old age

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An HbA1c value above eight percent is often tolerated in older patients - especially if they are in poor health. But new data shows that this is causing mortality rates to skyrocket.

The measured value HbA1c is a particularly sensitive long-term indicator for diabetes - much more meaningful than a direct blood sugar measurement. It allows conclusions to be drawn about the blood sugar concentrations of the last eight to twelve weeks. The more often and longer the blood sugar was increased, the higher the HbA1c value.

Hemoglobin plus sugar

The red blood pigment hemoglobin, to which a glucose molecule is attached, is hidden behind the name HbA1c. In healthy people, the HbA1c value is around 30mmol / mol (millimoles per mole) or, in other words, around five percent. The official guidelines recommend that type 2 diabetics keep an HbA1c value of 6.5 to 7.5 percent.

In the case of older patients, especially those with poor health, this value is often no longer taken so precisely. Priya Palta and her colleagues from the John Hopkins Bloomberg School of Public Health in Baltimore have now examined to what extent this has a negative effect on the survival rate.

The risk of dying increases

For their study, they analyzed the data of over 7,300 participants over 65 years of age, including around 1,300 diabetics. Over half of the test subjects died during the study period of almost nine years.

The result: Diabetics with an HbA1c value of over 8 to 8.9 percent had a 60 percent higher risk of dying within the nine years compared to those with a value below 6.5. Patients with values ​​of over nine percent even by 80 percent.

Also not endangered by diabetics

However, it was not only among participants with diagnosed diabetes that an increased HbA1c value drove up mortality: test subjects in whom diabetes had not yet been diagnosed, with an HbA1c value of over 6.5 percent, had an increased HbA1c value of at least 30 percent Risk of dying during the observation period compared to people without diabetes with values ​​of 5.0 to 5.6 percent.

"Our results support the notion that better glycemic control is important in reducing mortality," write Palta and colleagues.

Mechanisms unclear

What mechanisms are behind this is still unclear. "One possible explanation is that a higher HbA1c level exacerbates cardiovascular complications and subsequently increases the risk of death," the researchers said. In addition, a higher HbA1c value could be a marker for suboptimal self-management and this could lead to a higher risk of diabetes-related complications such as diseases of the kidneys and capillaries.

Source: Priya Palta et al .: Hemoglobin A1c and Mortality in Older Adults With and Without Diabetes: Results From the National Health and Nutrition Examination Surveys (1988-2011). Diabetes Care. Doi: https://doi.org/10.2337/dci16-0042

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