engleski

INFLUENCE OF ERYTROPOIETIN ON COGNITIVE FUNCTION IN MAINENTANCE HEMODIALYSIS PATIENTS

Introduction and Aims: Cognitive impairment is common among maintenance hemodialysis (HD) patients. Anemia has been identified as a risk factor for cognitive impairment in HD patients, but little is known about influence of erythropoietin on cognitive functions before and after HD session. In this study, Symbol Digit Modalities Test (SDMT), Trail Making Test, form A (TMT A) and Complex Reactiometer Drenovac (CRD series), a battery of computer generated psychological tests were used to assess possible relationship between erythropoietin treatment and cognitive function in maintenance HD patients. Methods: A selected population of 50 (aged 61.40±10.84 years) adult patient on maintenance HD (3.80±2.82 years) were investigated. Data of EPO administration usage per week (EPO_week IU/week) and EPO administration usage per week per kg of body weight (EPO_week_kg) were assessed from patient’s records 3 weeks retrospectively before cognitive testing. Assessment of cognitive functions was performed one hour before HD and one hour after HD treatment by CRD series tests to measure simple visual discrimination of signal location, short-term memory, simple convergent visual orientation and convergent thinking test. Results of CRD-series tests were given as total time of test solving (TT) and minimum time of test item solving (MT). Higher CRD-series tests scores (TT and MT measured in seconds) indicate poorer cognitive performance. Also, SDMT was used to measure oculomotor abilities and hand- eye coordination. Higher SDMT score indicated better cognitive performance. Furthermore, TMT A measure attention, visual scanning, motor speed and planning ability. Lower scores indicating better cognitive function. Results: In this group of HD patients we found statistically significant negative correlations between total EPO_weekly dose and cognitive test scores. Also, statistically significant negative correlations between EPO_weekly_/kg dose and cognitive test scores were found as presented in Table 1. Those HD patients with higher EPO_weekly and EPO_weekly_kg dose performed better on cognitive testing (needed less time to perform CRD series tests and TMT test and reached higher test score on SDMT). In order to test possible independent influence of total EPO_weekly and EPO_weekly_kg dose on cognitive performance, a partial correlation with hemoglobin as control variable was done. The results showed a statistically significant positive correlation between total EPO_weekly dose and SDMT score before HD (r=0.284, p=0.044). Conclusions: These results demonstrated that higher EPO dose is correlated with better cognitive performance and also showed possible independent effect of supplementation with EPO on cognitive functions. It still remains unknown whether this is solely due to an improvement in the blood count or an independent effect of supplementation with EPO. Future research, with larger number of participants in a prospective research model, should continue to examine which cognitive domains are particularly related to EPO treatment in HD patients.

ERYTROPOIETIN, COGNITIVE FUNCTION

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