Abstract Type : Oral presentation
Abstract Submission No.: A-0432
Abstract Topic : Renal Conservative Care + Geriatric Nephrology + Sarcopenia

Association of Estimated Glomerular Filtration Rate-Adjusted Proteinuria with Kidney Failure in Older Patients with Moderate-to-Severe CKD

Sungmi Kim¹, Sojung Youn², Young Youl Hyun³, Sungjin Chung⁴, Soon Hyo Kwon⁵, Sung Joon Shin⁶, Gang-Jee Ko⁷, Jae Won Yang⁸, Suk Young Kim⁹, Yu Ah Hong⁹
¹Department of Internal Medicine-Nephrology, The Catholic University of Korea Eunpyeong St. Mary's Hospital, Korea, Republic of
²Department of Internal Medicine-Nephrology, The Catholic University of Korea Bucheon St. Mary's Hospital , Korea, Republic of
³Department of Internal Medicine-Nephrology, Kangbuk Samsung Medical Center, Korea, Republic of
⁴Department of Internal Medicine-Nephrology, The Catholic University of Korea Yeouido St. Mary's Hospital , Korea, Republic of
⁵Department of Internal Medicine-Nephrology, Soonchunhyang University Seoul Hospital, Korea, Republic of
⁶Department of Internal Medicine-Nephrology, Dongguk University Ilsan Hospital, Korea, Republic of
⁷Department of Internal Medicine-Nephrology, Korea University Guro Hospital, Korea, Republic of
⁸Department of Internal Medicine-Nephrology, Wonju Severance Christian Hospital, Korea, Republic of
⁹Department of Internal Medicine-Nephrology, The Catholic University of Korea Daejeon St. Mary's Hospital , Korea, Republic of

Objectives : In older patients, age-related glomerulosclerosis reduces functional filtration surface, potentially increasing the protein burden per functioning nephron despite similar levels of total proteinuria. However, the prognostic significance of estimated glomerular filtration rate (eGFR)-adjusted proteinuria remains unclear in older patients with chronic kidney disease (CKD).
Methods : Among 1,220 patients aged ≥70 years with CKD stage ≥3 enrolled between 2021 and 2022 in a Korean multicenter prospective cohort, 791 were included in the final analysis. Patients were categorized into four groups based on the predetermined thresholds for the urine protein-to-creatinine ratio (UPCR) adjusted for eGFR (<1.0, 1–5, 5–10, and ≥10). Kidney failure was analyzed using Fine and Gray competing-risk models accounting for death.
Results : During a median follow-up of 27 months (IQR 6–44), 156 patients (19.7%) progressed to kidney failure and 81 (10.2%) died. Patients with higher eGFR-adjusted for UPCR had a greater prevalence of diabetes, higher systolic blood pressure, and lower hemoglobin and albumin levels. In multivariable competing-risk analyses, increasing categories of eGFR-adjusted for UPCR showed a graded association with the risk of kidney failure. Compared with <1.0, adjusted hazard ratios (HRs) were 3.26 (95% confidence interval (CI) 1.80–5.89) for 1–5, 5.15 (2.64–10.04) for 5–10, and 11.27 (5.68–22.36) for ≥10 (all P<0.01). Notably, 89 (32.5) patients with modest proteinuria (0.15–0.5 g/g) were reclassified into higher eGFR-adjusted for UPCR category of 1–5 with the rest corresponding to that of <1.0. Among patients with marked proteinuria (>1.0 g/g), 55 (28.1%), 56 (28.6) and 85 (43.4) patients were evenly reclassified into eGFR-adjusted for UPCR of 1–5, 5–10, and >10, respectively.
Conclusions : In older patients with moderate-to-severe CKD, eGFR-adjusted proteinuria was independently associated with kidney failure, supporting its potential utility for risk stratification.