Abstract and Introduction
Background: Acute kidney injury (AKI) is associated with long-term morbidity and mortality. The effects of AKI on neurocognitive functioning remain unknown. Our objective was to quantify neurocognitive impairment after an episode of AKI.
Methods: Survivors of AKI were compared with age-matched controls, as well as a convenience sample of patients matched for cardiovascular risk factors with normal kidney function (active control group). Patients with AKI completed two assessments, while the active control group completed one assessment. The assessment included a standardized test: the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS), and a robotic assessment: Kinarm.
Results: The cohort consisted of 21 patients with AKI, 16 of whom completed both assessments, and 21 active control patients. The majority of patients with AKI had Kidney Disease: Improving Global Outcomes Stage 3 AKI (86%), 57% received dialysis and 43% recovered to ≤25% of their baseline serum creatinine by their first assessment. Compared with the RBANS, which detected little impairment, the Kinarm categorized patients as impaired in visuomotor (10/21, 48%), attention (10/20, 50%) and executive tasks (11/21, 52%) compared with healthy controls. Additionally, patients with AKI performed significantly worse in attention and visuomotor domains when compared with the active controls. Neurocognitive performance was generally not impacted by the need for dialysis or whether kidney function recovered.
Conclusions: Robotic technology identified quantifiable neurocognitive impairment in survivors of AKI. Deficits were noted particularly in attention, visuomotor and executive domains. Further investigation into the downstream health consequences of these neurocognitive impairments is warranted.
Acute kidney injury (AKI) defined by the Kidney Disease: Improving Global Outcomes (KDIGO) criteria affects one in five hospitalized adults. AKI is particularly prevalent in patients who undergo cardiovascular surgery, or who are critically ill. Regardless of the cause of AKI, patients who experience an episode of AKI have an increased risk of morbidity and mortality.[2–4]
AKI often occurs in the context of multi-organ dysfunction, either due to the inciting injury affecting multiple organs simultaneously, or as an indirect result of kidney dysfunction. The brain may be particularly vulnerable to dysfunction in the context of AKI. It has been hypothesized that inflammation, uremia, cytotoxicity, osmolality disturbances and alterations in blood–brain barrier permeability are possible mechanisms underlying cerebral dysfunction in patients with AKI. These pathophysiological processes may lead to impaired neurocognitive performance in individuals with AKI.
The neurocognitive outcomes for survivors of AKI have not been extensively studied. Using administrative data, two retrospective studies have demonstrated that a diagnosis of AKI was an independent risk factor for dementia.[7,8] More recently, AKI has been shown to be associated with long-term neurocognitive impairment in children with severe malaria. In patients with chronic kidney disease (CKD), the high burden of neurocognitive impairment is well-described, and affects the domains of attention, memory and executive function. We also recently demonstrated that robotic technology can precisely quantify impairments in visuomotor function in patients with CKD. In contrast, there are no prospective data on adult neurocognitive impairment after AKI.
The objective of this prospective observational study was to use robotic technology (Kinarm) to quantify neurocognitive impairment in patients who recently experienced an episode of AKI. In this study, neurocognitive performance was compared with both healthy controls, as well as an active control group: patients matched for cardiovascular risk factors (but without any history of kidney disease). We hypothesize that Kinarm will be able to identify impairments in patients with AKI that are not detected using a traditional clinical assessment tool, and that patients with AKI will perform worse than patients without kidney disease.
Nephrol Dial Transplant. 2022;37(2):285-297. © 2022 Oxford University Press