Reviewed by Dr. Stephanie Chiao
McAdams-DeMarco, Mara A., et al. Journal of the American Society of Nephrology (2016): ASN-2016080816

As access to kidney transplantation has improved for older patients and patients are living longer with multiple medical problems prior to KT, KT recipients are becoming increasingly at risk for age-related conditions, such as dementia. This study was therefore performed to examine the rates of post-KT dementia as well as the effects of dementia on transplant outcomes.

The study examined data from Medicare claims on 40,918 KT recipients aged ≥55 years. It found that the 10-year risk of post-KT dementia was 5.1% for KT patients aged 55-60, 7.2% for those 60-65, 11.0% for those 65-70, 15.6% for those 70-75, and 17% for those 75 and older. For those who developed dementia, the 10-year risk of mortality was 86.7% and death-censored graft loss was 43.1%. This translates to a 1.5 fold increased risk of graft loss and a 2.4 fold increased risk of mortality compared to KT recipients who did not develop dementia. Predictors of dementia included older age, female sex, black race, fewer years of education, and diabetes at the time of transplantation. Participants were less likely to develop dementia if they had a calcineurin inhibitor-free maintenance immunosuppression regimen.

For a reference, the Framingham study found an incidence of dementia of 1-1.5% in adults aged 65, 7.4-7.6% in adults aged 75. KT recipients, therefore, are at a significantly increased risk of dementia compared to the general older adult population. This may be related to the significant burden of vascular pathology often found in ESRD patients in combination with the neurotoxic side effects of immunosuppression post-KT. KT recipients who develop dementia have significantly worse outcomes in terms of mortality and graft loss, which may be related to the debilitating effects of dementia. Impaired self-care, medication management, nutrition, and ability to communicate can lead to increased post-KT complications, such as infection or rejection, facilitating the process of graft loss and mortality. When considering kidney transplantation, the risks of dementia must be weighed against the burden of continuing dialysis, and once transplantation has occurred, providers must be vigilant about screening for cognitive impairment and assessing ADLs in order to optimize patient survival and quality of life.