Effect of Severe Hypoglycemia on Myocardial Cardiac Function in Type 1 Diabetes

Objective: Associations between severe hypoglycemia (SH) and cardiovascular disease (CVD) have been reported in epidemiological studies. Mechanisms for the relationship between SH and CVD are not well understood. While associations of HbA1c and traditional CVD risk factors with myocardial function in subjects with type 1 diabetes in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study have been reported, it is unknown whether an association of SH with myocardial function exists. Methods: We evaluated cardiac magnetic resonance (CMR) data of 1017 subjects. Associations of SH with CMR parameters using generalized linear models were examined. At time of CMR, subjects had been followed over ~ 22 years. SH was defined as SH requiring assistance of another party. A subset was defined as SH accompanied by coma and/or seizure (SHCS). Results: At time of CMR, 660 subjects had a SH history (407 subjects with coma and/or seizures). Median age [interquartile range] was 50 [44, 54] years, 48% were females, and median diabetes duration was 26.6 [23.5, 31.4] years. SH was positively associated with end diastolic volume (EDV) by +4 ml, p<0.01 and end systolic volume (ESV) by +2.7 ml, p<0.01, left ventricular mass (LVM) by +2.8 mg, p<0.05, and negatively correlated with ejection fraction by -0.8%, p<0.05. Its SHCS subset was positively associated with EDV by +3.4 ml, p<0.01, LVM by 2.6 mg, p<0.05, stroke volume by +1.9 ml, p<0.05, and cardiac output by +0.15 L/min, p<0.05. Sensitivity analyses were consistent with results. Conclusion: The effect of SH on cardiac function might be one of the mechanisms to explain the association between SH and CVD. It needs to be examined whether SH is associated with myocardial scars. Further studies are required to investigate whether the magnitude of SH effect on myocardial function increases with older age and leads to a clinically relevant CV event, especially in diabetic subjects with established coronary heart disease. Disclosure E. R. Fahrmann: None. L. J. Adkins: None. R. Lamichhane: None. H. Driscoll: None.