Diabetes prevalence in patients with takotsubo syndrome in a Polish cohort: the meaning of ‘controls’

I read with great interest the report by Zalewska-Adamiec et al. [1] about the 95 patients (89% female) from the northern-eastern part of Poland who were hospitalised with takotsubo syndrome (TTS) in the years 2008–2012. The authors have contrasted the TTS cohort with 101 female patients with an anterior ST-segment elevation acute myocardial infarction (STEMI), and found that TTS is not a benign condition; it has an in-hospital phase characterised by serious complications, but long-term outcomes at followup are better than in patients with STEMI. Similar to the ones with STEMI, the TTS patients had a past medical history of hypertension (63.2% vs. 68.3%), but a lower prevalence of diabetes mellitus (DM) (12.6% vs. 29.7%), and hyperlipidaemia (36.8% vs. 64.4%) [1]. It has recently been reported that the prevalence of DM is low in patients with TTS [2], and it has been postulated that this may have pathophysiological connotations. Accordingly, the underlying DM-mediated peripheral neuropathy, with its attendant autonomic nervous system peripheral neuropathy, exerts a halting/ameliorating influence on the autonomic sympathetic nervous system, whose unbridled surge is thought to trigger TTS. Indeed, even if blood-borne catecholamines are at the roots of TTS, instead of a surge of the autonomic sympathetic nervous system, DM is characterised by at-