Utility of continuous performance test (MOXO-CPT) in children with pre-dialysis chronic kidney disease, dialysis and kidney transplantation

Background: Children with chronic kidney disease and on kidney replacement therapy may have neurocognitive and psychosocial disorders. Although kidney transplantation improves quality of life, psychological problems may exist in children who undergo kidney transplantation. Herein, we aimed to investigate attention-deficit hyperactivity disorder-like symptoms with MOXO-continuous performance test in children with pre-dialysis chronic kidney disease, dialysis and kidney transplantation.

Methods: The MOXO-continuous performance test measures four domains of attention-deficit hyperactivity disorder-like symptoms, including attention, timeliness, hyperactivity and impulsivity. Patients with at least three scores < - 1.5 standard deviations were considered as positive to MOXO-continuous performance test. Test scores of the pre-dialysis chronic kidney disease, dialysis (divided into peritoneal dialysis and hemodialysis subgroups) and kidney transplantation groups were compared. Correlations of test scores with the patient's clinical and laboratory characteristics and effects of hospitalizations and schooling were assessed.

Results: Seventy-two patients aged 13.3 ± 3.4 years (23 with kidney transplantation, 23 on dialysis and 26 with pre-dialysis chronic kidney disease) were evaluated. Overall MOXO-continuous performance test positivity was 29%. No differences were detected between the three groups concerning total or z scores. Attention and timeliness z scores were significantly higher in females (p = 0.004 and p = 0.008, respectively). Age was positively correlated to attention and timeliness total scores (p = 0.000, r = 0.445 and p = 0.004, r = 0.243, respectively), and inversely correlated to hyperactivity total scores (p = 0.000, r = - 0.415).

Conclusions: Prevalence of attention-deficit hyperactivity disorder-like symptoms in the study population was much higher than that of pediatric attention-deficit hyperactivity disorder. We believe that the MOXO-continuous performance test is a valid supportive measure for evaluation of attention-deficit hyperactivity disorder diagnosis in children with various stages of chronic kidney disease or on kidney replacement therapy.