Effect of Vitamin D status on QTc interval in type 2 diabetes mellitus

Objectives Diabetes mellitus (DM) is associated with autonomic neuropathy and metabolic abnormalities. These predispose the patients to prolongation of QTc and risk of arrhythmias and sudden cardiac death. Vitamin D may also cause QTc prolongation. We hypothesized that concomitant Vitamin D deficiency and Type 2 DM may act in synergy to prolong QTc interval. Methods Newly diagnosed Type 2 DM patients were recruited from Department of Endocrinology. Lead II ECG was acquired for 5 min during supine rest using a digital data acquisition system. QTc interval extraction was performed using software. 25-hydroxy Vitamin D estimation was done using Chemiluminescence method. Patients were divided into two groups- Vitamin D deficient and insufficient (VDD/I) and optimal (VDO) as per standard criteria. QTc intervals were compared between the two groups. Results Sixty-five patients participated in the study. Age was comparable between the groups (p=0.67, Unpaired t-test). There was no significant difference amongst QTc intervals between the groups (p=0.19, Mann Whitney test). Also, there was no significant correlation between Vitamin D levels and QTc intervals assessed using Spearman's correlation coefficient. Conclusions While it seems plausible, coexisting Vitamin D deficiency and Type 2 DM probably do not act in synergy to prolong QTc interval. These findings merit future research on larger cohorts to investigate the relationship between Vitamin D status and newly diagnosed Type 2 DM on QTc intervals.