Relationship Between Time-in-Range and Hemoglobin A1c in Patients with Diabetes in Pregnancy
Poster #: 096
Session/Time: A
Author:
Jillian Wakefield Jetmore, BS
Mentor:
Marwan Ma'ayeh, MD
Research Type: Clinical Research
Abstract
INTRODUCTION:
This study evaluates the relationship between blood glucose time-in-range (TIR) and Hemoglobin A1c (HbA1c) in pregnant individuals with Type 2 Diabetes (T2DM) or Gestational Diabetes (GDM).
METHODS:
Retrospective study of pregnant individuals with T2DM or GDM who were monitored with a continuous glucose monitor (CGM). CGM data was analyzed from the 4 weeks preceding a scheduled HbA1c measurement. TIR was defined as the percentage of time with a blood glucose in the 60-140mg/dL range. Univariable and multivariable analyses were used to evaluate the association between TIR and HbA1c of <6.5%. Receiver operating characteristic (ROC) analysis was performed to evaluate the performance of TIR alone versus a model including both TIR and diabetes type in predicting the subsequent HbA1c <6.5%.
RESULTS:
156 individuals were included: 129 with T2DM and 27 with GDM. There was a negative correlation between HbA1c and the TIR value in the preceding 4 weeks (r = -0.67, p<0.001). In the multivariable logistic regression, both a higher TIR (aOR 2.61, 95% CI 1.19-6.00; p=0.018) and a diagnosis of T2DM (aOR 0.22, 95% CI 0.05-0.74; p=0.023) were independently associated with a HbA1c <6.5%. The area under the curve (AUC) for TIR alone in predicting HbA1c <6.5% was 0.793 (95% CI: 0.723-0.864). The addition of diabetes type to the model resulted in a marginal, non-significant improvement in the AUC to 0.803 (95% CI: 0.736-0.870), which may be due to relatively lower number of GDM pregnancies in the cohort where TIR is better at predicting normal HbA1c. TIR >70% had a sensitivity of 86.4% and a specificity of 100% in GDM and a sensitivity of 69.7% and a specificity of 71.4% in T2DM for predicting a subsequent HbA1c <6.5%.
CONCLUSION:
In pregnant individuals with T2DM or GDM, HbA1c is strongly correlated with TIR values in the prior 4 weeks. Our results confirm that TIR is as appropriate measure of glycemic control and that a 70% threshold is a valid target. TIR is also an independent predictor of achieving glycemic control as measured by HbA1c and may be obviate the need for HbA1c assessment.
This study evaluates the relationship between blood glucose time-in-range (TIR) and Hemoglobin A1c (HbA1c) in pregnant individuals with Type 2 Diabetes (T2DM) or Gestational Diabetes (GDM).
METHODS:
Retrospective study of pregnant individuals with T2DM or GDM who were monitored with a continuous glucose monitor (CGM). CGM data was analyzed from the 4 weeks preceding a scheduled HbA1c measurement. TIR was defined as the percentage of time with a blood glucose in the 60-140mg/dL range. Univariable and multivariable analyses were used to evaluate the association between TIR and HbA1c of <6.5%. Receiver operating characteristic (ROC) analysis was performed to evaluate the performance of TIR alone versus a model including both TIR and diabetes type in predicting the subsequent HbA1c <6.5%.
RESULTS:
156 individuals were included: 129 with T2DM and 27 with GDM. There was a negative correlation between HbA1c and the TIR value in the preceding 4 weeks (r = -0.67, p<0.001). In the multivariable logistic regression, both a higher TIR (aOR 2.61, 95% CI 1.19-6.00; p=0.018) and a diagnosis of T2DM (aOR 0.22, 95% CI 0.05-0.74; p=0.023) were independently associated with a HbA1c <6.5%. The area under the curve (AUC) for TIR alone in predicting HbA1c <6.5% was 0.793 (95% CI: 0.723-0.864). The addition of diabetes type to the model resulted in a marginal, non-significant improvement in the AUC to 0.803 (95% CI: 0.736-0.870), which may be due to relatively lower number of GDM pregnancies in the cohort where TIR is better at predicting normal HbA1c. TIR >70% had a sensitivity of 86.4% and a specificity of 100% in GDM and a sensitivity of 69.7% and a specificity of 71.4% in T2DM for predicting a subsequent HbA1c <6.5%.
CONCLUSION:
In pregnant individuals with T2DM or GDM, HbA1c is strongly correlated with TIR values in the prior 4 weeks. Our results confirm that TIR is as appropriate measure of glycemic control and that a 70% threshold is a valid target. TIR is also an independent predictor of achieving glycemic control as measured by HbA1c and may be obviate the need for HbA1c assessment.