Implementation of KDIGO CKD Screening and Its Prognostic Implications in Community-Dwelling Adults Aged 75 Years or...

Background: Chronic kidney disease (CKD) is highly prevalent in older adults, yet distinguishing pathological CKD from age-related decline in kidney function remains challenging. KDIGO guidelines recommend combined assessment of estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (uACR), but implementation in primary care is uncertain. We evaluated CKD screening patterns, KDIGO risk categories, and the prognostic value of eGFR and albuminuria for all-cause mortality in adults aged ≥75 years. Methods: We conducted a retrospective population-based cohort study of 587,603 community-dwelling adults aged ≥75 years using Primary Care electronic records. Complete CKD screening was defined as at least two eGFR and two uACR measurements ≥ 3 months apart during 2015-2019. CKD prevalence, KDIGO risk categories, and 40-month all-cause mortality were assessed. Multivariable Cox regression models evaluated the independent and joint associations of eGFR and albuminuria with mortality. Results: Only 19.0% of participants underwent complete KDIGO-recommended screening, mainly because of limited albuminuria testing. Among screened individuals, CKD prevalence was 25.7%, with over half classified as high or very high KDIGO risk. Mortality increased progressively with declining eGFR, increasing albuminuria, and worsening KDIGO risk. Macroalbuminuria (HR 1.87, 95% CI 1.75-2.00) and eGFR < 30 mL/min/1.73 m² (HR 1.91, 95% CI 1.79-2.04) were independently associated with mortality. Conclusions: Complete KDIGO-recommended screening was performed in only one in five adults aged ≥75 years, identifying a major implementation gap in primary care. Albuminuria provided prognostic information beyond eGFR, improving identification of older adults at highest risk of death. These findings support systematic combined eGFR-uACR assessment to improve risk stratification, guide kidney-protective management, and inform healthcare planning for ageing populations.