Pathogenesis of cognitive complaints in patients on hemodialysis.

Memory-concentration complaints are a common symptom among end-stage renal disease patients receiving hemodialysis. However, assuming an organic basis for these complaints might lead to unnecessary and expensive testing. To further explore the etiology of cognitive complaints, this study examined the contribution of demographic, neuropsychological, medical, affective, and personality variables to memory-concentration complaints in 426 hemodialysis patients. Following stepwise multiple regression to identify the best predictor variables within each domain, hierarchical multiple-regression analysis determined the significant predictors of memory-concentration complaints. Education, digit symbol score, and hemoglobin jointly accounted for approximately 7% of the variance. Cognitive (psychological) symptoms of depression explained an additional 9% of variance. Somatic symptoms of depression did not significantly contribute, whereas state anxiety did. Finally, personality variables collectively accounted for another 9% of variance. Overall, the model accounted for 28% of explained variance in memory-concentration complaints. These findings demonstrate that affect and personality factors are more predictive of memory-concentration complaints in hemodialysis patients than are neuropsychological or medical factors. The clinical implication is that the initial response to memory-concentration complaints in these patients should be evaluations of psychological condition.