# Validation of a predictive calculator for optimal glycemic control and time-in-tight-range following CGM sensor placement in type 1 diabetes and pancreatic diabetes: a prospective study

## TL;DR

This study tested a tool that predicts how well people with diabetes will manage their blood sugar using a glucose monitoring device.

## Contribution

The study prospectively validated a predictive calculator for glycemic control outcomes after CGM initiation in real-world settings.

## Key findings

- The calculator showed moderate discrimination with an AUC of 0.639 for predicting optimal glycemic control.
- It correlated significantly with time in range and time in tight range metrics.
- Smoking was associated with non-completion of the study follow-up.

## Abstract

Continuous glucose monitoring (CGM) has improved diabetes management, yet not all patients benefit equally. We previously developed a predictive calculator using clinical and socioeconomic variables to estimate the likelihood of achieving optimal control after CGM initiation. This study prospectively validated the calculator in a real-world cohort.

A single-center prospective study included 102 adults with type 1 or pancreatic diabetes using multiple daily insulin injections, followed for three months. Optimal control was defined as time in range (TIR, 70–180 mg/dL) > 70% and time below range (TBR, <70 mg/dL) < 4%. Model performance was assessed using ROC analysis and correlation tests.

Of 102 participants, 85 completed follow-up (median age: 53.6 years; 48% women; median diabetes duration: 12.9 years; baseline HbA1c: 7.6%). Thirty-three (38.8%) achieved optimal control. The calculator showed moderate discrimination (AUC = 0.639) and significant correlations with TIR (p = 0.230, p = 0.023) and time in tight range (TITR, 70–140 mg/dL) (p = 0.271, p = 0.019). Overall accuracy was 61.9%, lower than in the original cohort. Smoking predicted non-completion (p = 0.038).

The calculator shows moderate accuracy in predicting glycemic control and TITR after CGM initiation. CGM adherence remains a challenge, warranting further study in publicly funded healthcare settings.