The “Perfect” HbA1c

Not necessarily.

A low HbA1c can look excellent on a laboratory report. But HbA1c represents an average blood glucose level over approximately two to three months.

It does not tell us whether a person's glucose is dropping dangerously low during the night.

Why Hypoglycemia Matters More With Age

As we grow older, hypoglycemia can become particularly dangerous. A low glucose level during sleep may go unnoticed until it causes significant symptoms.

Possible warning signs include:

• Night sweats or unusual nightmares
• Morning headaches
• Confusion after waking
• Dizziness or weakness
• Unexplained falls
• Shaking or sweating
• Loss of consciousness in severe cases

For an older adult living alone, a severe nighttime low can become a medical emergency.

HbA1c Does Not Tell the Whole Story

Imagine two people who both have an HbA1c of 7%.

One person stays between 90 and 170 mg/dL most of the time. Another person swings between 50 and 250 mg/dL.

Their HbA1c may look similar, but their glucose patterns are completely different.

What Is Time in Range?

Time in Range (TIR) is the percentage of time glucose remains within a predefined target range.

For many people using continuous glucose monitoring (CGM), the commonly used range is:

CGM can also show how much time a person spends below or above the target range.

However, these targets are not identical for every older adult. Age, frailty, other medical conditions, medications, cognitive status, and hypoglycemia risk all need to be considered.

Why “Lower Is Always Better” Can Backfire

In younger, healthier people, intensive glucose control may provide important long-term benefits.

But in an older adult with multiple health problems, the balance between benefit and risk can be different.

• The benefits of intensive control may take years to appear.
• The consequences of severe hypoglycemia can occur immediately.
• A nighttime low can cause dizziness or a fall.
• A fall can result in fractures, hospitalization, and loss of independence.

Who Should Pay Particular Attention?

CGM-based glucose patterns can be especially useful for older adults who:

• Use insulin.
• Take sulfonylurea medicines.
• Have experienced previous hypoglycemia.
• Have unexplained falls.
• Have nighttime sweating or nightmares.
• Have difficulty recognizing low blood sugar.
• Live alone.
• Have multiple medical conditions or frailty.

Ask for an Individualized Target

There is no single HbA1c target that is appropriate for every person over 60.

A healthy older adult may have a different target from someone who is frail, has cognitive impairment, or has several chronic medical conditions.