CKD has already been a major public health problem around the world. And it affects 10.8% of Chinese adult population and imposes substantial morbidity and cost [1]. It's reported by large-scale epidemiological studies have demonstrated that patients with CKD have an increased risk of cardiovascular events including death, congestive heart failure, myocardial infarction, and stroke [2]. And up to 45% of pre-dialysis CKD patients may die before reaching end stage renal disease (ESRD), which makes cardiovascular disease (CVD) the leading cause of death in CKD [3]. The reasons for this high cardiovascular (CV) mortality are not fully understood. HRV, a non-invasive and simple technique based on the electrocardiogram, has been used as markers of autonomic modulation of the heart [4]. HRV could also be used to detect CAD [5]. Reduced HRV has been proved to be a significant independent risk factor for mortality and cardiac death in CVD [6], CKD [7] and even healthy populations [8].

The EZSCAN system (Impeto Medical, Paris, France), with reverse iontophoresis technology, is a noninvasive and accurate method to assess sudomotor function [9]. Patients with type 2 diabetes, for poor glucose control, have injured autonomic nerve fibers, which cause sudomotor dysfunction [10]. And the EZSCAN system has been tested as a tool for detecting diabetes and its complication of autonomic dysfunction [9,11].

Therefore, in a cross-sectional study, we investigated the association of ESC of EZSCAN results with HRV in non-dialysis CKD patients.