Clinical predictors of individual cognitive fluctuations in patients undergoing hemodialysis

Ana S. Costa, Frances E. Tiffin-Richards, Bernhard Holschbach, Rolf D. Frank, Athina Vassiliadou, Thilo Krüger, Frank Eitner, Theresa Gross, Nadim J. Shah, Jörg B. Schulz, Jürgen Floege, Kathrin Reetz

Research output: Contribution to journalArticleResearchpeer-review

38 Citations (Scopus)


Background Cognitive impairment in hemodialysis (HD) patients is frequent and mediated by several factors. It is unclear which patients are more susceptible to cognitive variations around the dialysis cycle and which clinical factors may play a mediator role. We aimed to answer these issues by investigating intraindividual changes within the dialysis cycle. Study Design Cross-sectional observational study with repeated measures. Setting & Participants 47 HD patients and 40 controls without kidney disease, both without history of neurologic disease. Predictors Dialysis vintage, disease duration, vascular risk factors, comorbidity index score, intradialytic weight change, frequency of hypotensive episodes, and biochemical levels (hemoglobin, leukocytes, urea, creatinine, sodium, and potassium). Covariates included demographics (age, education, and sex). Outcomes & Measurements Significant individual deterioration in attention and executive functions (phasic and intrinsic alertness, Stroop test, and Trail Making Test) after dialysis, as measured by a regression-based reliable change method. Regression models were used to identify clinical predictors of individual cognitive decline after dialysis. Results After dialysis, patients primarily showed prolonged reaction times and psychomotor slowing. However, individual-based analyses revealed that fluctuations in attention and executive functions were present in only a minority of patients. Significant individual fluctuations on particular attention and executive tasks were associated moderately with intradialytic hypotensive episodes, as well as with psychoactive medication, and were predicted weakly by blood leukocyte count, sodium level, dialysis vintage, and volume. Limitations Small sample size; patient group younger and healthier than the overall HD population, limiting generalizability. Conclusions Only a minority of patients exhibit significant individual cognitive fluctuations, predominantly showing deterioration after dialysis in attention and executive functions. Susceptibility to such fluctuations was predicted in part by both HD-dependent and -independent factors.

Original languageEnglish
Pages (from-to)434-442
Number of pages9
JournalAmerican Journal of Kidney Diseases
Issue number3
Publication statusPublished - Sep 2014
Externally publishedYes


  • attention
  • Chronic kidney disease
  • cognition
  • cognitive impairment
  • executive function
  • fluctuations
  • hemodialysis
  • neuropsychological assessment
  • psychomotor speed
  • reliable change
  • variations in cognitive function

Cite this