Cardiovascular

Machine learning predictors of cardiovascular autonomic neuropathy in type 2 diabetes: insights from a prospectively collected single-center registry.

TL;DR

CARTs remained essential for accurate CAN classification and staging; routinely available clinical variables provided complementary phenotypic information but were insufficient to robustly distinguish CAN categories without CART data, particularly CAN0 and CAN1.

Key Findings

Almost all patients with T2DM in the registry had at least one borderline or abnormal cardiovascular autonomic reflex test result.

  • Among 693 patients with T2DM, 19 (2.7%) had completely normal autonomic function.
  • 674 (97.3%) exhibited at least one borderline or abnormal CART result.
  • Data came from a prospective single-center registry using standardized CARTs based on Ewing's protocol.

Greater CAN severity was associated with older age, longer diabetes duration, higher systolic blood pressure, and poorer renal function.

  • Patients were classified as CAN0 (no or borderline CAN), CAN1 (early CAN), or CAN2 (definite or severe CAN).
  • Demographic, anthropometric, clinical, laboratory, and medication data were analyzed.

The CART-inclusive XGBoost model achieved perfect discrimination of CAN categories in its best iteration, with all five CARTs among the leading predictors.

  • Weighted AUC was 1.00 and accuracy 100% in the best iteration.
  • All five CARTs ranked among the leading predictors by SHAP values.
  • Because CAN categories are defined by CART results, this model essentially reflects the classification criteria.

Excluding CART variables sharply reduced model performance in patients with T2DM only.

  • Weighted AUC fell to 0.64.
  • Class-specific AUCs were 0.59 for CAN0, 0.59 for CAN1, and 0.68 for CAN2.

Adding non-diabetic controls without abnormal CART results to the CART-excluded model improved performance, most for CAN0.

  • Weighted AUC improved to 0.78.
  • Class-specific AUCs were 0.85 for CAN0, 0.78 for CAN2, and 0.70 for CAN1.
  • CAN1 remained the most difficult category to discriminate.

Age, diabetes duration, and renal function markers were recurrent non-CART predictors, while other feature groups contributed in category- and model-specific ways.

  • Anthropometric, hematological, metabolic, and treatment-related features showed category- and model-specific contributions.
  • Feature contributions were interpreted using SHapley Additive exPlanations (SHAP) values.

UMAP showed substantial overlap among CAN categories, particularly for CAN1.

  • This is consistent with the limited ability of non-CART clinical variables to separate categories.
  • Early CAN (CAN1) was least separable.

ML may support multidimensional phenotyping and hypothesis generation but cannot replace standardized autonomic testing.

  • Routinely available clinical variables were insufficient to robustly distinguish CAN categories without CART data, particularly CAN0 and CAN1.
  • CARTs remained essential for accurate CAN classification and staging.

What This Means

This study used machine learning on data from 693 people with type 2 diabetes who had standardized heart-related autonomic nerve tests, to see which routine clinical features predict cardiac autonomic neuropathy (CAN), a nerve complication that raises cardiovascular risk. Nearly everyone (97.3%) had at least one borderline or abnormal test result. More severe CAN was linked to older age, longer diabetes duration, higher systolic blood pressure, and worse kidney function. When the autonomic test results themselves were given to the model, it sorted patients into categories almost perfectly, but this is expected since those tests define the categories. When the tests were removed and only routine clinical information (age, lab values, medications and so on) was used, accuracy fell substantially (weighted AUC 0.64). Adding non-diabetic control participants improved performance (0.78), mainly for identifying people without CAN. Early CAN was hardest to identify in every analysis, and visual mapping showed the categories overlapped heavily. This research suggests that routine clinical data carry some information about CAN, but not enough to replace formal autonomic testing, especially for spotting early disease. Machine learning may help researchers explore patterns and generate hypotheses. The study came from a single center, so the findings may not apply to all populations.

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Citation

Farkas K, Vedelek V, Vámos M, Csajbók &, Baczkó I, Zádori J, et al.. (2026). Machine learning predictors of cardiovascular autonomic neuropathy in type 2 diabetes: insights from a prospectively collected single-center registry.. Frontiers in endocrinology. https://doi.org/10.3389/fendo.2026.1965013