May the In-Hospital Mortality Gap between STEMI Patients with and without Diabetes Mellitus Be Reduced? The Cardio-Renal Hypothesis

Abstract Background and Aims Diabetes mellitus (DM) is a frequent comorbidity in ST-elevation-myocardial infarction (STEMI) patients and carries a higher risk of in-hospital mortality. We recently demonstrated that the higher in-hospital mortality of STEMI patients with DM, when compared to that of patients without DM, is mainly associated with their more frequent cardiac and renal dysfunction. These exploratory results prompted us to hypothesize that this higher risk in DM patients is mediated by their lower cardio-renal functional reserve. Methods and Results We included 5,152 STEMI patients treated with primary angioplasty. By using an advanced statistical methodology (path analysis), able to clarify the putative causal paths between variables of interest, we reported that the higher in-hospital mortality of STEMI patients with DM is possibly caused by its adverse impact on cardio-renal function. Conclusion This statistical approach allows to reinforce the well-known notion that DM is associated with an increased in-hospital mortality risk in STEMI and sheds lights on the causal relationship among DM, cardio-renal dysfunction, and higher in-hospital mortality. Whether the mortality gap between DM and non-DM patients with STEMI can be reduced by pharmacological strategies combining cardio-renal protective effects is an intriguing question that deserves an answer in the future.