Beta-cell Insufficiency.

'Beta-cell failure' is a frequently used term to describe the structural and functional inability of the cells to fulfil their metabolic responsibility. This editorial reviews the anatomy and physiology of the beta cell, and describes factors which regulate this. The authors focus on semantics, comparing the phrases 'beta-cell failure', 'functional mass', and 'beta-cell insufficiency'. They suggest the use of 'beta-cell insufficiency', with descriptors such as 'partial' and 'complete', or 'reversible' and 'irreversible', to convey betacell dysfunction in type 2 diabetes. A three-phase taxonomic structure: beta-cell sufficiency, partial/reversible beta-cell insufficiency and complete/irreversible beta-cell insufficiency, is proposed as a tool to understand pathophysiology and facilitate therapeutic decision-making.