Identification of Rapid Decline of Kidney Function in Older Adults with Different Types of Aging

Background: This study aims to assess the role of glomerular filtration rate (GFR) combined with urine albumin-creatinine ratio (ACR) in predicting rapid kidney function decline (>30% decline in GFR within 2 years) across older adults with three types of aging (healthy aging, aging with comorbidities, aging with nephropathy). Methods: Categorical analyses were conducted using data from the Rugao Longevity and Aging Study (RLAS) cohort in China (470 older adults with healthy aging and 505 with comorbidities) and healthcare data from Huashan Hospital of Fudan University (315 older adults with nephropathy) between 2011 and 2022. Corrected (age) absolute risk probabilities (aAR) were calculated for different GFR and ACR intervals, stratified by aging category. Finally, the importance of different categories of GFR and ACR in different aging populations for determining rapid decline in kidney function was identified based on random forest (RF) models. Results: Compared to the healthy group, the risk of rapid decline of kidney function was generally higher in the comorbidity group and highest in the nephropathy group across all GFR combined with ACR categories. The risk thresholds varied among the three populations: for the healthy group, ACR >30 mg/g combined with GFR <75 ml/min/1.73 m2 (moderate risk); for the comorbidity group, ACR >30 mg/g (moderate risk), particularly with GFR <60 ml/min/1.73 m2 (high risk); and for the nephropathy group, at all stages (moderate risk), particularly ACR >30 mg/g combined with GFR <75 ml/min/1.73 m2(high risk). Besides, GFR is of the most importance in distinguishing rapid decline in kidney function, but the discrimination of GFR decreases with the occurrence of comorbidities and kidney diseases, while the discrimination of ACR increases in this two populations. Conclusion: The thresholds for GFR and ACR to predict rapid decline in kidney function in the elderly population need to be established according to different types of aging. Funding: Government Support – Non-U.S.