Assessment of the Cognitive State in Hemodialysis Patients – Relation to the Potential Risk Factors for Abnormalities

Background. A risk for cognitive impairment is suggested in long term maintenance haemodialysis (HD). The aim of the study was to analyze and compare the cognitive state of HD patients at baseline and after two years, considering the potential risk factors. Methods. The sample consisted of 7 females and 14 males, mean age 53.7 ± 9.9 years, range 32-69, with mean HD duration of 90.7 months. They were non-diabetics, free of intercurrent complications, with normal hepatic function, without vascular disease and history of psychiatric disorders. The cognitive state was assessed at baseline and after two years via Mini-Mental State Examination (MMSE). Following potential risk factors were observed: hypertension, dyslipidemia, common carotid arteries intima media thickness, anemia, erythropoietin (EPO) therapy, smoking, adequacy of HD and education. Results. Prevalence of scores suggesting cognitive impairment was found in 9.5% of patients at baseline (none at re-test). During two year interval change in MMSE score did not indicate cognitive deterioration. Performance was significantly better at the re-test (28.7 ± 1.6 vs. 27.7 ± 1.7; p=0.004) followed by significant increase in hematocrit (Hct) (33.5 ± 4.3 vs. 26.6 ± 4.3; p 0.01) and hemoglobin (Hb) concentration (10.8 ± 1.3 vs. 9.4 ± 1.6; p 0.01). Hb concentration of <10 g/dl significantly correlated to lower baseline MMSE score. Correction of anemia was especially beneficial to patients aged > 55 years and to subjects with the University level education. Other risk factors were not significantly associated to the cognitive function. Conclusions. MMSE represents a practical test to track the changes in patient’s cognitive state. Anemia proved to be an important factor in cognitive functioning of HD patients (especially in those aged over 55 years). This population should be routinely screened for a cognitive impairment in the future.