Reframing Diabetes Mellitus as a Multiaxial Disease Continuum: The Diabetes Severity Classification (DSC) Framework

Diabetes mellitus (DM) is increasingly recognised as a heterogeneous and dynamic disorder that extends beyond a simple dichotomy between type 1 and type 2 diabetes. While the traditional classification remains anchored in dominant pathogenetic mechanisms, it provides limited insight into disease severity, progression and complication risk, and offers little guidance for individualised prevention and treatment. Growing evidence of overlapping phenotypes, variable trajectories and divergent risks underscores the need for a complementary framework capable of integrating biological mechanisms with clinical evolution. We propose the Diabetes Severity Classification (DSC) as a multiaxial, stage-based framework that conceptualises DM as a dynamic continuum. The DSC integrates four interrelated axes-β-cell functional reserve, insulin resistance and metabolic flexibility, glycaemic control and complication burden-and organises disease evolution into five stages, ranging from predisposition to complication-dominant disease. Rather than replacing existing aetiological classifications, the DSC operates orthogonally-that is, independently but in parallel-to them, providing a structured approach to describe disease state, severity and trajectory across all forms of DM. By explicitly incorporating cardiovascular risk, metabolic heterogeneity and evolving complication burden, the DSC aims to improve clinical interpretability and risk stratification, particularly at earlier stages when preventive interventions may have the greatest impact. Conceptually aligned with established staging systems in other chronic diseases, such as the cardiovascular-kidney-metabolic framework, the DSC offers a standardised language to bridge pathophysiology and clinical decision-making, supporting a more individualised and prevention-oriented approach to diabetes care.