Comparison of annual eGFR decline among primary kidney diseases in patients with CKD G3b-5: results from a REACH-J CKD cohort study

Background Disease-specific trajectories of renal function in advanced chronic kidney disease (CKD) are not well defined. Here, we compared these trajectories in the estimated glomerular filtration rate (eGFR) by CKD stages. Methods Patients with multiple eGFR measurements during the 5-year preregistration period of the REACH-J study were enrolled. Mean annual eGFR declines were calculated from linear mixed effect models with the adjustment variables of baseline CKD stage, age, sex and the current CKD stage and the level of proteinuria (CKDA1-3). Results Among 1,969 eligible patients with CKDG3b-5, the adjusted eGFR decline (ml/min/1.73 m 2 /year) was significantly faster in diabetic kidney disease (DKD) patients and polycystic kidney disease (PKD) patients than in patients with other kidney diseases (DKD, − 2.96 ± 0.13; PKD, − 2.82 ± 0.17; and others, − 1.95 ± 0.05, p < 0.01). The declines were faster with higher CKD stages. In DKD patients, the eGFR decline was significantly faster in CKDG5 than CKDG4 (− 4.10 ± 0.18 vs − 2.76 ± 0.20, p < 0.01), while these declines in PKD patients were similar. The eGFR declines in PKD patients were significantly faster than DKD patients in CKDG4 (− 2.92 ± 0.23 vs − 2.76 ± 0.20, p < 0.01) and in CKDA2 (− 3.36 ± 0.35 vs − 1.40 ± 0.26, p < 0.01). Conclusion Our study revealed the disease-specific annual eGFR declines by CKD stages and the level of proteinuria. Comparing to the other kidney diseases, the declines in PKD patients were getting faster from early stages of CKD. These results suggest the importance of CKD managements in PKD patients from the early stages.