March 05, 2020
2 min read

Study names best-performing cognitive impairment screening test for patients on dialysis

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An analysis of screening tests designed to assess cognitive function determined the Montreal Cognitive Assessment had the highest predictive ability for detecting severe impairment in patients receiving maintenance hemodialysis.

“There is currently no recommended screening test for cognitive impairment in patients on hemodialysis, despite recognition by the ESKD Functional Status Technical Expert Panel in 2014 that ‘cognition is an important aspect of functional status and determinant of the patient’s ability to manage his/her disease, live independently, and participate in care decisions,’” David A. Drew, MD, MS, of Tufts Medical Center in Boston, and colleagues wrote.

Adding that “comprehensive neurocognitive testing to diagnose cognitive impairment requires the use of multiple cognitive tests and a significant time commitment,” the researchers suggested dialysis facilities could benefit from an easy-to-administer and readily available screening test. However, they argued, cognitive tests used in the general population may not perform well in patients with kidney disease.

Drew and colleagues examined the predictive ability of six common screening tests (Mini Mental State Examination, the Modified Mini Mental State Examination, the Montreal Cognitive Assessment, the Trail Making Test Part B, the Mini-Cog test and the Digit Symbol Substitution Test) after first performing a set of comprehensive neurocognitive tests on 150 patients. The tests looked at memory, attention and executive function. Based on these tests, patients were classified as having normal cognitive function (21%) or cognitive impairment (mild, 17%; moderate, 33%; severe, 29%).

Reference: Drew DA, et al. J Am Soc Nephrol. 2020;doi:10.1681/ASN.2019100988.

Researchers found that the though Trail B and Digital Symbol performed “reasonably well” (area under the curve of 0.73 and 0.78, respectively), the Montreal Cognitive Assessment had the highest overall predictive ability for severe cognitive impairment (AUC, 0.81), while also demonstrating high sensitivity (86%). They hypothesized these tests may have performed better than the others because of their ability to assess executive function which, the researchers explained, is “a cognitive domain involved in planning and carrying out tasks.” Furthermore, they wrote, “because patients with kidney disease are more likely to display deficits in executive function, these tests may better capture cognitive deficits when compared with tests that do not include a significant executive-function component.”

Due to the results of this study, coupled with its wide availability (translated into > 50 languages), low cost (free, though there is a fee for administrator-training certification) and ease of use, the researchers recommend dialysis facilities use the Montreal Cognitive Assessment when conducting cognitive function assessments. – by Melissa J. Webb

Disclosures: Drew reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.