Une étude scandinave propose de démembrer les deux grands types de diabète de l'adulte en cinq catégories : même les Scandinaves peuvent perdre le Nord !

The current classification of diabetes states into two categories (type 1 and type 2) suffers from well-recognized drawbacks and the characterization of subtypes remains somewhat difficult. This is due to the fact that diabetes, especially type 2, is a con-tinuum across individuals ranging from those who progress towards insulin-requiring diabetes to others (a majority of them) who never need insulin throughout their lifetime. In order to decipher this conundrum, Scandinavian investigators have attempted to distinguish different categories (clusters) of diabetes using six variables: Glutamic Acid Decarboxylase (GAD) antibodies, age at diagnosis, BMI, HbA1c, and homeostasis model assessment (HOMA) of insulin-secretion and resistance. The proposed clusters were a priori selected on the main patients' characteristics and a posteriori confirmed using the six aforementioned variables. As these variables have the same meaning as the criteria used for selecting the clusters, this procedure is a perfect example of “tautol-ogy”, a redundant approach that consists to validate a proposal with a tool, which has no chance to refute the initial propositional formulation. In addition, the Scandinavian authors seem to have forgotten that the HOMA is poorly relevant at an individual level except when it is longitudinally used in the same person. Consequently, the HOMA has never been proposed for guiding the therapeutic choices in diabetes, even though the Scandinavian authors suggest that their “novel” classification is the first step towards “precision medicine”. Finally, it is a statement of the obvious to say that the times to chronic kidney disease, to retinopathy, and to sustained insulin use, are shorter in the clusters of patients who were found to be the most insulin-resistant and/or insulin-deficient, respectively. At the end, we are left with the mixed impression of a study conducted with a poor methodology, and of a classification that has a small probability to be applicable to other countries and ethnic groups.