Diaphragmatic Dysfunction Contributes to Dyspnoea, Fatigue, and Snoring in Haemodialysis Patients

Background: Muscle wasting is associated with increased mortality and morbidity in chronic kidney disease (CKD) patients, especially in the haemodialysis (HD) population. Little is known regarding diaphragmatic dysfunction under CKD conditions. Methods: We conducted a cross-sectional study at the Institute of Nephrology, Southeast University, involving 103 HD patients and 103 healthy volunteers as normal control. Ultrasonography was used to evaluate diaphragmatic function, including diaphragm thickness and excursion. We further examined the prevalence of diaphragmatic dysfunction and its influence factor and relationship with debilitating symptoms (dyspnoea, hiccups, and fatigue) in HD patients.   Results: HD patients showed lower end-inspiration thickness of the diaphragm at total lung capacity and thickening fraction compared to controls. The velocity and excursion of the diaphragm were significantly lower in the HD patients during deep breathing. Changes in diaphragm displacement from quiet breathing to deep breathing (△m) were lower in HD patients than in controls. After multivariate adjustment, hemoglobin level may have effects on diaphragmatic functions such as diaphragm excursion at total lung capacity (DMTLC) and △m. Diaphragm thickness during deep breathing was positively correlated with weight and was greater in males than in females. We also found that the incidence of dyspnoea and snoring and the fatigue scores, all of which were related to diaphragmatic dysfunction, were significantly higher in HD patients than in controls (all p < 0.01). In addition, diaphragmatic dysfunction was confirmed in a CKD mouse model. Conclusions: Improving diaphragm function through targeted therapies may positively impact clinical outcomes in HD patients. Trial Registration Information: Chinese Clinical Trials Registry, 2018ZDKYSB167. Retrospectively registered on May 18, 2018. Funding Statement: This work was supported by grants from the National Natural Science Foundation of China (81700618), the Natural Science Foundation of Jiangsu Province (BK20181487), the China Young Nephrologist Research Project, and a Southeast University High Level Thesis Project to Bin Wang. It was supported by additional grants from the National Natural Science Foundation of China (81720108007, 81470922, 31671194, 81720108007, and 81670696), the National Key Research Programme (2018YFC130046, 2018YFC1314000) and the Clinic Research Center of Jiangsu Province (BL2014080) to Bi-cheng Liu. Declaration of Interests: None of the authors has any conflict of interest to declare. Ethics Approval Statement: The study protocol was approved by the Ethics Committee of Zhongda Hospital affiliated to Southeast University. The details of the study were explained to each patient; if he or she agreed to participate, a written informed consent was signed.