#876 Albuminuria and the risk of dementia and different dementia subtypes: the Stockholm Creatinine Measurements (SCREAM) project

Abstract Background and Aims Studies investigating the association of chronic kidney disease and dementia predominantly focused on estimated glomerular filtration rate (eGFR) rather than albuminuria. The few studies focusing on albuminuria reported conflicting results, probably due to a lack of power, not taking into account the different dementia subtypes, not adjusting for eGFR, and the use of different albuminuria measurement techniques. This study therefore investigated the eGFR-independent risk of all-cause and type-specific dementia associated with albuminuria, quantified as urine albumin-creatinine ratio (ACR) and by dipstick, in a large population. Method We included subjects from the Stockholm Creatinine Measurements (SCREAM) project without a history of dementia and with age ≥65 years. The main analyses involved 138 688 subjects with at least one ACR test, and for sensitivity analyses, we involved 170 572 subjects with at least one dipstick proteinuria test. Albuminuria was quantified as KDIGO albuminuria A1-A3 stages. The primary outcome was incidence of all-cause dementia, and the key secondary outcomes were incidence of type-specific dementia. Dementia incidence was ascertained by record linkage with the national dementia registry (SveDem). ICD-10 coding was also used to classify subtypes only when there were no available dementia records in SveDem. Multivariable Cox regression models were used to calculate hazard ratios (HRs, 95% CIs) crude, and adjusted for confounders including baseline eGFR. Results During a median follow-up of 3.9 (IQR, 1.8-7.2) years, 9 970 subjects developed de novo dementia. After multivariable adjustment including baseline eGFR, subjects with an ACR of 30-299 mg/g or ≥300 mg/g had a 26% (HR, 1.26; 95% CI, 1.20-1.32) and 36% (HR, 1.36; 95% CI, 1.24-1.50) higher risk of developing all-cause dementia, respectively, when compared to subjects with an ACR <30 mg/g. Subjects with an ACR of 30-299 mg/g also presented a higher risk of developing several type-specific dementia, including Alzheimer's dementia (HR, 1.09, 95% CI, 1.01-1.17), vascular dementia (HR, 1.35, 95% CI, 1.22-1.48), and unspecified dementia (HR, 1.54, 95% CI, 1.41-1.69). No significant associations between albuminuria and the incidence of Lewy body dementia and Parkinson's Disease with dementia, frontotemporal dementia, as well as other types of dementia were observed. These results were generally robust in several sensitivity analyses, including replicating our main analyses in subjects with a dipstick proteinuria test instead of an ACR. Conclusion Increased albuminuria is associated with a higher risk of all-cause, Alzheimer's, and vascular dementia, independent of baseline eGFR and different albuminuria measurement techniques.