Comparative Study Between Hemodialysis and Hemodiafiltration Regarding Effect on Cognitive Function

Abstract

Objective: Cognitive impairment (CI) is very common in chronic kidney disease (CKD) and is strongly associated with increased mortality. Hemodiafiltration (HDF) is a dialysis modality that is thought to offer better clearance of middle molecules, more stability of intradialytic blood pressure and better cognitive state of end stage renal disease (ESRD) patients. So, we aim to compare cognitive function in hemodialysis (HD) versus HDF patients.Materials and Methods: In a cross sectional study, 100 patients were divided as: 50 patients maintained on HD 3 regular sessions per week, 50 patients maintained on 3 regular sessions of HDF per week. Patients with dementia or delirium, Patients with psychosis or bipolar disorder, Patients who are under the influence of a substance or alcohol, Patients with previous history of cerebrovascular stroke were excluded. History including demographic data, etiology of ESRD and comorbidities was taken. Cognitive assessment was done using Mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA). Blood samples were taken to measure kidney function tests, metabolic profile, complete blood count, thyroid and parathyroid function tests.Results: Cognitive assessment using MoCA showed that in HD group: 12 patients were found to have CI and 38 patients were normal, while in HDF group only 4 patients were found to have CI and the other 46 patients had normal cognitive function.Conclusions: Our study shows that the MoCA test is a valid screening test for CI in both HD patients and HDF patients. It demonstrated higher sensitivity for screening patients with mild CI than MMSE. CI is often under-diagnosed due to the patients’ unawareness of their cognitive deficits. Therefore, screening tests would be more appropriate for these patients. The MoCA test which is sensitive to executive dysfunction seems to be more adaptable to assess CI in both groups of this study; HD patients and HDF patients; HDF is a modality of dialysis with better outcome regarding cognitive function in ESRD patients.