Comparison of the extent and pattern of cognitive impairment among predialysis, dialysis and transplant patients: a cross sectional study from Australia

Aim: The aim of this study was to compare the extent of cognitive impairment and the types of cognitive deficits in an Australian cohort of four patient groups with end stage kidney disease. Characteristics predicting the presence of cognitive impairment were also evaluated. Methods: Observational cross sectional study of one hundred and fifty five patients with end stage kidney disease recruited from a regional Australian renal unit. Eligible participants included those whose estimated Glomerular Filtration Rate was < 30 ml/min per 1.73m2; were undertaking peritoneal or hemodialysis, or had received a kidney transplant. The Montreal Cognitive Assessment tool was used to screen the study participants for cognitive impairment and evaluate cognitive deficits. Cognitive impairment was defined as a total Montreal Cognitive Assessment tool score ≤24/30. Results: The extent of cognitive impairment varied between the four groups with end stage kidney disease. Factors predicting the presence of cognitive impairment included undertaking dialysis, age ≥65, male gender, and the presence of diabetes or cerebrovascular disease. Deficits in executive function, attention, language, visuospatial skills, memory and orientation were common amongst the study participants, and these deficits varied according to which end stage kidney disease group the participants were in. Limitations to the study included the cross sectional design and that the presence of confounders like depression were not recorded. Conclusion: The impact of disparities in the cognitive capabilities identified in this study are likely to be far reaching. Tailoring of education and self management programs to the cognitive deficits of individuals is required.