Endocrine Abstracts

Objective: Diabetes is an independent risk factor for sudden cardiac death. Prolongation of the QT interval on the ECG increases the risk of arrhytmias and sudden death, and the increased prevalance of QT prolongation is an independent risk factor for cardiovascular death in diabetic patients. Low vitamin D levels are also associated with cardiovascular mortality. The aim of this study was to investigte the relationship between QT interval and vitamin D levels in type 2 diabetic patients.

Materials and method: One hundred and thirty type 2 diabetic patients (62 females and 68 males, mean age: 62.17±7.15 S.D. years) and fourty five age matched healthy volunteers (23 females, and 22 males, mean age: 60.97±5.67 S.D. years), for control group included in this study. Diabetic patients were classified in two groups according to HbA1c levels. Group 1 (HbA1c<6.5) Group 2 (HbA1c<6.5). In the ECG recordings, QT duration, corrected QT duration (QTc) and corected QT dispersions (QTd) were measured. 25 hydroxyvitamin D levels, calcium, phosphors, and blood glucose levels determined in all groups.

Results: Diabetic patients had significantly longer QTc than the control group (P=0.02). QTd was similar in diabetic and control group. However in diabetic cohort QTd was longer in group 1 patients (P=0.04). Diabetic patients with low vitamin D levels have longer QTc time (P=0.07). Fasting glucose levels and HbA1c levels were inversely corralated with vitamin D levels (P=0.03, r=−0.16 and P=0.03, r=−0.18 respectively). vitamin D levels were also inversely corralated with QTc (P=0.02, r=−0.17).

Conclusion: QTd prolonges in diabetic patients. Low levels of vitamin D increases this prolongation.