#2415 Estimated glomerular filtration rate thresholds associated with poor long-term outcomes in older patients with diabetes

Abstract Background and Aims Considering the natural decline of GFR with renal senescence, an age-adjusted estimated glomerular filtration rate (eGFR)-based chronic kidney disease (CKD) definition was recently proposed, which has been supported by that mortality risks start to increase at GFR <45 mL/min/1.73 m2 in older adults (≥65 years). However, the eGFR threshold for mortality and kidney outcomes in older patients with diabetes was less understood. We aimed to evaluate eGFR levels that raise the risk of mortality or end-stage kidney disease (ESKD) in older patients with diabetes. Method Older adult patients (≥65 years) with type 2 diabetes who visited our outpatient diabetes center during 2009 were retrospectively identified and followed up until 2017. Patients were categorized into four groups per their CKD-EPI equation-based eGFR: ≥60, 45–59, 30–44, and 15–29 mL/min/1.73 m2. Cox proportional hazard analysis for all-cause mortality and competing-risk analysis for ESKD (with a competing event of pre-ESKD death) were performed. Results Among 3,065 patients, 19%, 8%, and 2% of patients had eGFR 45–59, 30–44, and 15–29 mL/min/1.73 m2 at baseline, respectively. After adjusting various clinical covariates, including blood pressure, diabetes duration, urine albumin/creatinine ratio, HbA1c, serum cholesterol levels, and major comorbidities, patients with eGFR 30–44 and 15–29 mL/min/1.73 m2 had 1.51-fold (95% confidence interval [CI] 1.17–1.95, P < 0.001) and 2.66-fold (95% CI 1.87–3.79, P < 0.001) higher risks of mortality, respectively, whereas patients with eGFR 45–59 mL/min/1.73 m2 had a comparable risk (1.18, 95% CI 0.96–1.45, P = 0.127) to those with eGFR ≥60 mL/min/1.73 m2. Substitution hazard ratios for ESKD were 2.29 (95% CI 1.41–3.71, P = 0.001), 5.25 (95% CI 3.27–8.41, P < 0.001), and 16.74 (95% CI 9.73–28.80, P < 0.001) in patients with eGFR 45–59, 30–44, 15–29 mL/min/1.73 m2, respectively. In a subgroup of patients 75 or older (n = 800), patients with eGFR 45–59 mL/min/1.73 m2 exhibited comparable risks for both ESKD and mortality. Conclusion Reduced eGFR < 60 mL/min/1.73 m2 predicted an increased risk of ESKD in older patients with diabetes, suggesting that the current traditional eGFR threshold appears feasible. Thus, some high-risk individuals may be missed if age-adapted eGFR criteria with a lower eGFR threshold than 60 mL/min/1.73 m2 are universally applied for older adults ≥65 years.