Low prevalence of diabetes mellitus in patients with Takotsubo syndrome: A plausible "protective' effect with pathophysiologic connotations

Aims: The pathophysiology of Takotsubo syndrome is still elusive; coronary vasospasm, microvascular dysfunction, or catecholamine-mediated injury to the cardiomyocytes, effected by local release from the autonomic nerves and/or blood-borne catecholamines, are considered as tentative cause(s). Diabetes mellitus-induced autonomic neuropathy leads to a brain-heart disconnection, and it can conceivably ameliorate/block the effect of an unbridled adrenergic storm to the heart, and the emergence of Takotsubo syndrome. This study sought to evaluate the prevalence of diabetes mellitus in patients with Takotsubo syndrome. Methods and results: All the papers accessed in PubMed were reviewed, to evaluate the prevalence of diabetes mellitus and hypertension in Takotsubo syndrome patients, employing the rate of the latter as an index of how representative of the general population were the study patients, and the rate of the former as the focus of this investigation. Out of the 1932 papers, 959 were suitable for analysis, reporting on 33,894 patients (88.9% women) with Takotsubo syndrome. In five subanalyses, of all patients, patients reported individually, patients reported collectively in case series, patients 60 years old reported individually, and patients 65 years old reported individually, the prevalence of hypertension was 57.4%, 42.8%, 57.9%, 50.4%, and 52.2%, correspondingly, and comparable to the 65.4% shown by the National Health and Nutrition Examination Survey (NHANES). The prevalence of diabetes mellitus in the five subgroups was 16.8%, 10.2%, 17.0%, 11.9%, and 12.5%, correspondingly, and lower than the 26.9% found by the NHANES. Conclusion: The prevalence of diabetes mellitus in patients with Takotsubo syndrome is low. This insight may be useful for the diagnosis, pathophysiology unraveling, and employment of autonomic adrenergic blocking agents in the management of patients with Takotsubo syndrome.