Reply to comment on: Høi-Hansen T, Pedersen-Bjergaard U, Thorsteinsson B (2005) The Somogyi phenomenon revisited using continuous glucose monitoring in daily life. Diabetologia 48:2437–2438

Excerpt

To the Editor: Thank you for giving us the opportunity to respond to the letter from Iseda et al. [1]. We certainly acknowledge the extensive scientific contribution made by Dr Somogyi [2]. He concluded, amongst other things, after studying five patients that ‘excessive glycosuria (hyperglycemia) is an aftermath of hypoglycemia’ [3]. With the years, this phrase has been interpreted as nocturnal hypoglycaemia inducing high morning blood glucose values [4]. In our letter we rejected this clinical statement by showing that if patients have a nocturnal hypoglycaemic episode during the night there was a high probability that blood glucose the following morning was low [5]. This finding suggests that hormonal counter-regulation alone is not capable of inducing hyperglycaemic excursions in type 1 diabetic patients. Iseda et al. now raise the question of whether hyperglycaemia occurs later on in the day after a nocturnal hypoglycaemic episode. In this context it should be noted that the glycaemic response during the day after a night with hypoglycaemia is a complex result of carbohydrate intake (sometimes increased by the hypoglycaemic episode), insulin dosage (possibly reduced if morning glucose is low), prolonged action of counter-regulatory hormones (primarily cortisol and growth hormone), physical activity and other factors. This means that a hyperglycaemic excursion after an episode of nocturnal hypoglycaemia may be caused by reasons other than pure counter-regulatory insulin resistance. Nevertheless, we consider the question to be of clinical importance and have looked further into our data by studying hourly glucose values determined by a continuous glucose monitoring system (CGMS) for 4 h post-breakfast (Fig. 1) and the maximum value during the day.

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