“…The design of 15 studies was a prospective cohort design, and these studies sought to evaluate changes in cognitive function over time in patients with CKD [12,25,34,36,39,41,46,47,49,50,54,[59][60][61][62]66]. The comparative crosssectional studies compared patients with CKD with another patient group, and this method was utilized in 15 studies [33,35,37,40,[42][43][44]48,[51][52][53]55,56,63,64]. Of these studies, 12 utilized patients with a GFR greater than 60ml/min/1.73m 2 as a comparison group [33,35,40,43,44,48,[51][52][53]55,63,64], one study utilized patients on hemodialysis (HD) as a comparison group [56], and one study utilized both patients with a GFR greater than 60ml/min/1.73m 2 and patients on renal replacement therapy (HD, peritoneal dialysis, and transplant) as a comparison group…”