Late onset type 1 diabetesBMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e2827 (Published 30 April 2012) Cite this as: BMJ 2012;344:e2827
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In "Easily missed? Late onset type 1 diabetes", the authors do not discuss an alternative cause for ketoacidosis in an adult patient without a previous diagnosis of diabetes, namely ketosis-prone type 2 diabetes. This pathophysiological entity, first recognised in 1987, may occur in those either carrying a diagnosis of type 2 diabetes or having risk factors (such as obesity or a strong family history). Although the exact mechanism is as yet unclear, there is biochemical evidence of both marked insulin resistance and insulin hyposecretion. Ketosis-prone type 2 diabetes is increasingly recognised as a cause for unexplained diabetic ketoacidosis, particularly in certain ethnic populations.
If a patient with DKA is thought to have underlying type 2 diabetes and thus ketosis-prone type 2 diabetes, absence of islet cell autoantibodies at follow-up may support a decision to cease insulin and introduce dietary measures and oral hypoglycaemics. A significant proportion remains off insulin many years later.
In addition to ketosis-prone type 2 diabetes, there have recently been reports of "double diabetes", in which obese patients below 25 years of age exhibit islet cell autoimmunity but otherwise behave like type 2 diabetes. The recognition of LADA, ketosis-prone type 2 diabetes and double diabetes supports the authors' assertion that the distinction between type 1 and type 2 diabetes can sometimes be artificial.
 Lasserson D, Fox R, Farmer A. Late onset type 1 diabetes. BMJ 2012;344:e2827.
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Competing interests: No competing interests