Your HbA1c (A1c) is one part of your toolkit as a person with type 1 diabetes (T1D). This number cannot tell you everything about your diabetes health, but it can offer a general idea of where your blood sugar levels have been over the previous three months.

Recent research from the T1D Exchange Quality Improvement Collaborative (T1DX-QI) pinpoints which factors have the most impact on reaching A1c goals in adults and children/adolescents with T1D.

First: What is A1c, and why does it matter?

Your A1c level is essentially a measurement of how much glucose (sugar) is attached to the red blood cells throughout your body. Red blood cells have a lifespan of about three months which is why this measurement is often performed every three months at your T1D health care provider’s office.

The higher your blood sugar levels have been during the three months, the more glucose will be attached to your red blood cells. Higher A1c levels are associated with a higher risk of developing diabetes-related complications, including vision loss (retinopathy), numbness or amputation in your legs, feet, and toes (neuropathy), and kidney failure (nephropathy).

A1c levels at or below 7.0 percent are recommended to reduce your risk of diabetes-related complications. A1c goals should be personalized with your healthcare team’s support based on your needs as a person with diabetes.

What thousands of study participants tell us about reaching A1c targets

Both studies — adult and pediatric — used the following factors to assess what factors matter most in a person’s ability to reach A1c targets:

  • Sociodemographic (age, gender, relationship status, parental status, employment status, etc.)
  • Self-reported depression symptoms
  • Episodes of diabetic ketoacidosis (DKA)
  • Episodes of severe hypoglycemia
  • Diabetes device use (continuous glucose monitor [CGM], insulin pump, etc.)
  • Insurance type
  • Weight and body mass index (BMI)

After an extensive review of the collected data, researchers were able to pinpoint significant differences between different A1c levels. Let’s take a closer look at this data.

Study results: Which factors impact a child or teen’s A1c most?

The T1DX-QI study involved 16 clinics across the country with a total of 25,383 children and adolescents up to 18 years old living with T1D.

The breakdown of A1c levels among pediatric participants was:

  • Below 7%: 18% of participants
  • Between 7-9%: 44% of participants
  • Above 9%: 38% of participants

While there were no differences in A1c levels based on gender, other factors were significant.

Participants with A1c levels below 7% were:

  • Significantly more likely to be using a CGM and/or insulin pump
  • More likely to have private insurance
  • Less likely to have a depression or anxiety diagnosis
  • Less likely to experience acute complications, including DKA or severe hypoglycemia
  • More likely to be non-Hispanic white

Participants with A1c levels above 9% were:

  • Significantly less likely to be using a CGM and/or insulin pump
  • Less likely to have private insurance
  • More likely to have a depression or anxiety diagnosis
  • More likely to experience acute complications, including DKA or severe hypoglycemia
  • More likely to be a person of color
  • More likely to have lower social/economic status

“This study highlights social disparities in reaching glycemic targets and supports previous findings that CGM use is beneficial in effective management of blood glucose levels,” explained the report.

Study results: Which factors impact an adult’s A1c most?

The T1DX-QI study involved 15 clinics across the country with 12,035 participants 18 years or older with type 1 diabetes.

The breakdown of A1c levels among adult participants was:

  • Below 7%: 23% of participants
  • Between 7-9%: 44.5% of participants
  • Above 9%: 32.5% of participants

A1c levels based on age:

  • All age groups: most participants had A1cs between 7-9%
  • 19-25 years old: 17.4% had A1cs below 7%
  • 26-49 years old: 31.5% had A1cs below 7%
  • 50 years and older: 28.2% had A1cs below 7%
  • Younger adults had the highest percentage of A1cs above 9%

Participants with A1cs below 7% were:

  • More likely to use a CGM and/or insulin pump
  • More likely to have private insurance
  • Less likely to have depressive symptoms

Participants with A1cs above 9% were generally:

  • Young
  • Non-Hispanic Black
  • Experiencing more DKA episodes
  • Experiencing more severe hypoglycemia episodes
  • More likely to experience depressive symptoms
  • Less likely to have private health insurance
  • Less likely to use a CGM and/or insulin pump
  • More likely to have lower BMIs

A1c levels based on race/ethnicity:

  • 47.5% of non-Hispanic whites had an A1c between 7-9%
  • 74.6% of non-Hispanic whites do not attain an A1c below 7%
  • 43.6% of Hispanics had an A1c between 7-9%
  • 83.4% of Hispanics do not attain an A1c below 7%
  • 61.7% of non-Hispanic Blacks had an A1c above 9%
  • 90.2% of non-Hispanic Blacks do not attain an A1c below 7%
  • Reflections on both adult and pediatric studies

This research confirms a variety of theories and research concerning the critical impact of health equity, access to diabetes technology, and adequate health insurance.

“Previous studies have shown that patients with public health insurance were more likely to be hospitalized with DKA,” explains the study. “Health insurance coverage for diabetes technology, medications, and supplies varies among both public and private plans. High copayments, high-deductible plans, and limited formularies may act as barriers to the adoption and use of CGM and insulin pump therapy.”

Similar to research from T1D Exchange, there is a strong association between lower A1c levels and CGM use.

Despite an increased prevalence of type 1 diabetes among people of color, access to CGM technology is lower — demonstrating persistent healthcare inequality. The study emphasized a need for diabetes education programs that are also tailored to different cultural beliefs and experiences.

“Our work, and that of others, support the notion that there is a need to enroll more people from racial/ethnic minority groups in diabetes technology clinical trials. Most importantly, CGM and hybrid closed-loop insulin delivery systems should be made accessible to everyone in routine diabetes care.”

The study also highlighted the significance of depression screening and depression symptoms in relation to attaining an A1c below 7%.

“The prevalence of depression among people with type 1 diabetes is two to three times higher than in the general population,” explains the study. “Studies have shown that adults with comorbid depression and type 1 diabetes are less likely to achieve and maintain glycemic targets, have less interest in diabetes self-management, and are at increased risk for diabetes-related complications.”

Researchers emphasized how critical it is to screen all people with diabetes for depression — then provide immediate and adequate treatment.

Overall, the study highlights persistent issues of unequal healthcare based on race and ethnicity.

“Greater proportions of people from racial/ethnic minority groups did not reach glycemic targets than among non-Hispanic Whites. Having private health insurance and using advanced diabetes technology correlated with achieving an A1c <7%.”

This research continues the call for interventions that decrease racial/ethnic inequities in diabetes care among people with type 1 diabetes.