Supplementary Material for: Association between Acute Kidney Injury and Dementia: A Multi-database Cohort Study

Background: With the aging of population, dementia has emerged as a major public health concern, imposing a heavy society burden. However, the relationship between acute kidney injury (AKI) and the risk of dementia remains uncertain.
Methods: A total of 1,256,756 participants from the China Renal Data System (CRDS) database and 492,250 individuals from the UK biobank (UKB) dataset were included in the study. The study investigated the associations between acute kidney injury and and the onset of dementia. The exposure of interest was AKI. The outcome in both the CRDS and UKB cohorts was dementia.
Results: The CRDS cohort identified 7,878 patients with new-onset dementia, while the UK Biobank (UKB) recorded 9,926 dementia cases during follow-up. AKI showed a significant association with the risk of dementia in both the CRDS (adjusted HR: 1.22; 95%CI: 1.13-1.30, P < 0.001) and UKB cohorts (adjusted HR: 1.64; 95%CI 1.29-1.98, P = 0.005). In the CRDS cohort, patients with more severe AKI (stage 2-3 AKI) (aHR: 1.25; 95%CI 1.09-1.42, P = 0.008) exhibited a higher adjusted HR for dementia compared to those at AKI stage 1 (aHR: 1.21; 95%CI 1.11-1.30, P < 0.001). The association between AKI and dementia remained consistent across different subgroups in both cohorts.
Conclusion: Our findings demonstrated that AKI was associated with an elevated risk of all-cause dementia. Consequently, patients with history of AKI episodes necessitate vigilant monitoring for prevention of dementia.