Relationship between the cognitive performances and the renal functions in diabetic patients

Written by Gál Réka, Juhos Beáta-Mária, Kéri Johanna, Szabó Mónika, Mirela Gliga, Szatmári Szabolcs

Although the negative impact of diabetes on cognitive functions has been proved, and the role of cerebrovascular impairment is certain, the pathophysiological process which leads to cognitive deterioration remains still unknown. Our aim was to establish the connection between cognitive performance and renal functions in diabetic patients. We used MMSE, clock drawing, word fluency, Trail Making, Ranschburg–Ziehen tests and Beck-scale to evaluate diabetic patients from Diabetology and Nephrology Clinics from Târgu Mureș. We took into consideration the eGFR, hemoglobine level, potassium level and proteinuria. We examined 164 diabetic patients between 1 January 2013 and 1 March 2014. Cognitive deterioration was present in 39% of the nephropathic patients while in 41% of those who did not have renal impairment. A minor decrease of the GFR has already led to low cognitive results. The presence of cognitive deterioration was more significant at patients with low hemoglobin level. Results of Trail Making tests proved to be significantly weaker in the presence of proteinuria. Macroalbuminuria resulted in lower cognitive performance than microalbuminuria, and there was a difference in the appearance of depression between these two groups also. The cognitive performance of diabetic patients with renal impairment was worse as renal impairment reached a higher level, but it was not significantly different from patients with normal renal functions. The presence of proteinuria, which could refer to generalized small vessel impairment, resulted mainly in the destruction of the executive functions.


Keywords: diabetes, cognitive functions, proteinuria