The relationship between serum triglyceride level and heart rate variability in type 2 diabetes mellitus patients of North Karnataka

Abstract

Context: Diabetes mellitus is associated with an increased risk of mortality and morbidity from cardiovascular disease (CVD), which is mainly because of dyslipidemias. Several researchers have suggested that increased serum lipid fractions such as low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) were linked to decreased heart rate variability (HRV). Until now no papers have studied the association between serum triglyceride (TG) values and HRV. Aims: The objective of this study was to evaluate the relationship between serum TG levels and HRV in patients with type 2 diabetes mellitus. Materials and Methods: The study included 120 patients with type 2 diabetes mellitus (both male and female) of the age group 35–65 years, who visited Belgaum Diabetes Centre. They were selected by simple random sampling and recruited into the study. The patients were divided into three groups depending on the duration of diabetes. The study duration was 6 months. One-minute HRV was analyzed during deep breathing and defined as the difference between the shortest and the longest heart rate interval measured by Lead II electrocardiographic recording during six cycles of deep breathing using an electrocardiograph (BPL Cardiart 6208 BPL Medical Technologies Pvt Ltd, Bannerghatta Road, Bangalore, India). Kubios HRV Standard (version 3.0, Department of Applied Physics, University of Eastern Finland, Kuopio, Finland) software tool was used to analyze HRV. Fasting serum TG of all the patients (5mL of venous blood) was analyzed using semiautomatic analyzer (Transasia Erba Chem –5 Plu, Transasia Bio-Medicals, Andheri east, Mumbai, Maharashtra, India). Data were analyzed by using Statistical Package for the Social Sciences (SPSS 20.0 version, IBM Bangalore, Karnataka, India) software program, version 20.0. One-way analysis of variance (ANOVA) followed by Tukey’s multiple post hoc tests was used for comparison and Karl Pearson’s correlation coefficient was used to test the correlation between serum TG values and HRV in the three groups. The statistical significance was set at 5% level (P 0.05) between the three groups of patients with type 2 diabetes mellitus. The TG levels were significant and negative correlation was observed with HRV (r = 0.6141, P = <0.001) at 5% level of significance in all the three groups. Conclusion: From this study, we conclude that the hypertriglyceridemia in patients with type 2 diabetes mellitus could affect HRV. Further studies are needed to prospectively validate the impact of this novel finding.