Heart rate variability can be affected by gender, blood pressure, and insulin resistance--author's reply.

To the Editor,

We recently demonstrated decreased heart rate variability (HRV) values in patients with irritable bowel disease (IBS) in our study entitled “The effect of irritable bowel syndrome on carotid intima-media thickness, pulse wave velocity, and heart rate variability” published in the September issue of The Anatolian Journal of Cardiology 2014; 14: 525-30 (1). We read the letter entitled “Heart rate variability can be affected by gender, blood pressure, and insulin resistance” with great interest. As the authors kindly mentioned, HRV is a valuable tool for assessing autonomic dysfunction. Decreased HRV is associated with coronary artery disease, myocardial infarction, and cardiovascular mortality in patients with diabetes (2). Interestingly, insulin resistance and obesity, the prerequisites of diabetes mellitus, are also related to autonomic dysfunction (3). Our study included 30 women with IBS and 30 healthy control subjects. Although numeric differences existed in the prevalence of hypertension and diabetes mellitus compared with the control subjects, these were not statistically significant. Moreover, body mass index, fasting plasma glucose, and blood pressure values were not different between groups. Therefore, we do not believe that an important difference is present, which would have influenced our results with, regard to insulin resistance and obesity between the control and patient groups.