Limitations of Reporting Time Below Range as a Percentage.

Area of Science:

• Endocrinology
• Metabolic Diseases
• Medical Informatics

Background:

• Continuous glucose monitoring (CGM) provides key metrics like time in range (TIR) and time below range (TBR) for diabetes management.
• These metrics, alongside glycated hemoglobin (A1c), are crucial for optimizing patient care and are well-accepted by patients and providers.
• Time below range (TBR) quantifies glucose levels below specific thresholds (e.g., <70 mg/dL, <54 mg/dL) as a percentage.

Purpose of the Study:

• To identify and discuss limitations associated with expressing time below range (TBR) as an integer percentage.
• To highlight potential misinterpretations arising from the rounding of TBR values in ambulatory glucose profiles and automated insulin delivery system reports.
• To stimulate discussion on improved TBR reporting for enhanced clinical impact in diabetes management and hypoglycemia prediction.

Main Methods:

• Analysis of current practices in reporting time below range (TBR) from continuous glucose monitoring (CGM) data.
• Review of ambulatory glucose profile reports and automated insulin delivery system outputs.
• Identification of issues related to numerical rounding and integer percentage representation of TBR.

Main Results:

• Expressing time below range (TBR) as an integer percentage can obscure clinically significant variations in glucose control.
• Rounding of TBR values may lead to inaccurate assessments of hypoglycemia risk.
• Current reporting methods may not adequately stratify individuals at risk for severe hypoglycemic events.

Conclusions:

• Re-evaluation of how time below range (TBR) is reported is necessary for accurate diabetes management.
• Standardized and precise reporting of TBR is essential for effective clinical decision-making.
• Improved reporting can aid healthcare providers, patients, regulatory agencies, and payers in better stratifying and predicting severe hypoglycemia.