Introduction and Objective: Continuous Glucose Monitoring (CGM) generates complex time-series data often reduced to summaries (e.g., Time-in-Range). These metrics fail to capture the distributional shape of glycemic dynamics. This study applied Topological Data Analysis (TDA) and Wasserstein distances to identify intrinsic phenotypes of glycemic magnitude and evaluated their clinical relevance. Methods: We analyzed Dexcom G6 CGM data from 1,049 participants in the AI-READI dataset. We computed the pairwise Wasserstein Distance (mg/dL) between the glucose probability distributions of all participants. Hierarchical clustering was applied to the distance matrix to identify distinct subgroups. Clinical characteristics (HbA1c) and standard variability metrics (Coefficient of Variation) were compared across clusters using Kruskal-Wallis tests. Results: Topological clustering identified four distinct phenotypes with highly significant differences in clinical control (HbA1c p0.0001). Cluster 1 (Mean Glucose: 342.4 ± 20.3 mg/dL) represented a saturated phenotype with the highest HbA1c (10.0% ± 3.4%) but low variability (CV: 16.4% ± 5.0%), reflecting sustained hyperglycemia near the sensor limit. In contrast, Cluster 2 (Mean: 260.6 ± 16.6 mg/dL; HbA1c: 9.3% ± 1.4%) represented an erratic phenotype with the cohort's highest variability (CV: 23.6% ± 4.6%), distinct from the saturated group. Cluster 3 identified a moderate-variable phenotype (HbA1c: 6.7% ± 1.1%; CV: 22.8% ± 6.0%), while Cluster 4 represented tight control (HbA1c: 5.6% ± 0.7%; TIR: 96.0% ± 7.4%). Conclusion: Topological phenotyping effectively disentangles glucose level severity from instability. Specifically, it distinguishes patients with saturated, unvarying hyperglycemia from those with chaotic, high-amplitude fluctuations; distinct clinical states that standard HbA1c metrics often conflate. This approach offers a precise framework for stratifying type 2 diabetes phenotypes beyond averages. Disclosure B. Panny: None. Funding National Institutes of Health (1OT2OD032644)
Benjamin Panny (Fri,) studied this question.