Association of Postoperative Delirium with Incident Dementia and Graft Outcomes among Kidney Transplant Recipients

Background. Kidney transplant (KT) recipients have numerous risk factors for delirium, including those shared with the general surgical population (eg, age and major surgery) and transplant-specific factors (eg, neurotoxic immunosuppression medications). Evidence has linked delirium to long-term dementia risk in older adults undergoing major surgery. We sought to characterize dementia risk associated with post-KT delirium. Methods. Using the United States Renal Data System datasets, we identified 35 800 adult first-time KT recipients ≥55 y. We evaluated risk factors for delirium using logistic regression. We evaluated the association between delirium and incident dementia (overall and by subtype: Alzheimer's, vascular, and other/mixed-type), graft loss, and death using Fine and Gray's subhazards models and Cox regression. Results. During the KT hospitalization, 0.9% of recipients were diagnosed with delirium. Delirium risk factors included age (OR = 1.40, 95% CI, 1.28-1.52) and diabetes (OR = 1.38, 95% CI, 1.10-1.73). Delirium was associated with higher risk of death-censored graft loss (aHR = 1.52, 95% CI, 1.12-2.05) and all-cause mortality (aHR = 1.53, 95% CI, 1.25-1.89) at 5 y post-KT. Delirium was also associated with higher risk of dementia (adjusted subhazard ratio [aSHR] = 4.59, 95% CI, 3.48-6.06), particularly vascular dementia (aSHR = 2.51, 95% CI, 1.01-6.25) and other/mixed-type dementia (aSHR = 5.58, 95% CI, 4.24-7.62) subtypes. The risk of all-type dementia associated with delirium was higher for younger recipients aged between 55 and 64 y (Pinteraction= 0.01). Conclusions. Delirium is a strong risk factor for subsequent diagnosis of dementia among KT recipients, particularly those aged between 55 and 64 y at the time of transplant. Patients experiencing posttransplant delirium might benefit from early interventions to enhance cognitive health and surveillance for cognitive impairment to enable early referral for dementia care.