Severe iatrogenic hypoglycaemia requiring medical assistance is associated with concurrent prolongation of the QTc interval

Abstract

Aims: Hypoglycaemia has been shown to exert arrhythmogenic effects. Herein, we explore the association between severe hypoglycaemia requiring medical assistance and the length of the QT interval in patients with diabetes.

Methods: Data from a prospective study, conducted in eight tertiary hospitals, which recorded cases of hypoglycaemia from patients with diabetes seeking treatment at emergency departments (ED) were analyzed. The patients' electrocardiograms (ECGs), were compared to those of non-hypoglycaemic diabetic individuals, matched for age, gender and duration of diabetes, obtained during their scheduled follow-up visits. The corrected QT intervals (QTc) were calculated blindly by two cardiologists.

Results: ECGs from 154 patients presenting with hypoglycaemia were analyzed and compared to 95 matched controls. The mean QTc interval was significantly longer in patients with hypoglycaemia than in controls (441.9 ± 48.2 vs. 401.0 ± 29.6 ms, p < 0.001) A significantly higher proportion of hypoglycaemic patients had an abnormally prolonged QTc (≥440 ms) compared to controls (49.4% vs. 11.6%, p < 0.001). Among patients with hypoglycaemia, there was a statistically significant but rather weak negative correlation between QTc interval and plasma glucose at presentation (r: -0.183, p = 0.02).

Conclusions: In diabetic patients, hypoglycemia requiring medical assistance is associated with a significant prolongation of the QTc interval. The degree of this prolongation is associated with hypoglycaemia severity.