Frail kidney transplant (KT) recipients experience cognitive improvement soon after transplant surgery, but their cognitive performance slips over the next few years.
In a study of 665 KT recipients (mean age 52 years), 15% were frail based on the Fried physical frailty phenotype. Before transplantation, frail patients scored lower than their nonfrail counterparts on cognitive performance (89.0 vs 90.8 points) on the Modified Mini-Mental State Examination testing orientation, attention, language, and memory.
By 3 months post-transplant, cognitive performance had improved for both frail and nonfrail recipients, Nadia M. Chu, MD, of Johns Hopkins School of Medicine in Baltimore, and colleagues reported in the Journal of the American Society of Nephrology. From 1 to 4 years after transplantation, these improvements held steady in nonfrail recipients but declined by an average of 1.6 points per year in frail recipients. By 4 years, cognitive scores were 5.8 points lower for frail recipients than nonfrail recipients. Age, sex, race, education, and pre-transplant cognitive impairment did not explain the decline.
“This effect of being frail is approximately equivalent in our data to being 26.0 years older at time of KT,” Dr Chu and the team stated. They suggested that immunosuppressive medications act as a chronic physiologic stressor from which frail recipients struggle to recover. They also acknowledged that understudied post-transplant complications, such as infection, acute rejection, and metabolic derangements, might influence cognitive function.
“Clinicians may consider regularly monitoring cognitive function and mitigating cognitive decline among frail recipients as part of clinical practice for KT candidates to prevent cognitive impairment and dementia—a state of chronic and severe cognitive impairment more common among KT recipients aged 55+ years old than older adults generally,” Dr Chu and her collaborators said.
Potential interventions include cognitive training, exercise, and blood pressure management. “Additionally, transplant centers may consider targeting frailty among candidates before KT with interventions, such as exercise and resistance training, nutrition, geriatric assessment/management, and prehabilitation, to optimize recovery from surgical stressors.”
Chu NM, Gross AL, Shaffer AA, et al. Frailty and changes in cognitive function after kidney transplantation. J Am Soc Nephrol. 30. DOI:10.1681/ASN.2018070726