Cardiac Function Transition in Patients with Chronic Kidney Disease Undergoing Maintenance Hemodialysis in a High-Altitude Multi-Ethnic Region: A Comparative Study Between Yi and Non-Yi Ethnic Groups

Background: Cardiovascular disease is the leading cause of mortality in patients with chronic kidney disease (CKD), particularly among those undergoing maintenance hemodialysis (MHD). High-altitude exposure may further aggravate cardiovascular stress through chronic hypoxia. However, longitudinal data in multi-ethnic high-altitude dialysis populations remain limited. Objective: To evaluate changes in cardiac function in CKD stage 5/end-stage renal disease patients receiving MHD at high altitude and to compare findings between Yi and non-Yi ethnic groups. Methods: This retrospective study included 161 patients (103 Yi, 58 non-Yi) undergoing MHD in Ninglang Yi Autonomous County (mean altitude >2800 m). Clinical characteristics, laboratory parameters-including homocysteine (HCY)-and echocardiographic indices were assessed at baseline, 3 months, and 12 months. Longitudinal trends and ethnic differences were analyzed. Results: In the overall cohort, pulmonary artery systolic pressure (PASP) increased significantly over time (P=0.049), while the E/A ratio declined, indicating progressive diastolic impairment. Left ventricular ejection fraction (LVEF) remained stable At 12 months, Yi patients had higher HCY levels (P=0.034), lower albumin (P=0.010) and apolipoprotein A levels (P=0.044), and a higher incidence of aortic regurgitation (AR) (P=0.012). Baseline E/A ratio was higher in Yi patients (P=0.032). Conclusion: CKD patients undergoing MHD at high altitude exhibit dynamic changes in cardiac function, predominantly involving pulmonary pressure and diastolic parameters. Ethnic differences in selected biochemical and echocardiographic indices suggest the need for tailored cardiovascular monitoring in high-altitude multi-ethnic dialysis populations.