Factors associated with loss of renal function in patients with polycystic kidney disease: a nationwide real-world data analysis

Factors associated with kidney failure in advanced autosomal dominant polycystic kidney disease (ADPKD) patients have not been fully examined. This study investigated the factors associated with kidney failure in these patients. Using national registry data from 2015 to 2021, we analyzed the decrease in the estimated glomerular filtration rate (eGFR) and related factors in 3562 ADPKD patients who met the intractable disease criteria in Japan and were followed for more than 3 years (mean age, 50 years; 51% males). The primary outcome was a ≥ 30% decrease in the eGFR, and factors associated with the decrease in the eGFR were analyzed. To identify risk factors, a Cox proportional hazards model and classification and regression tree (CART) analysis were performed. The estimated eGFR decline was - 3.17 (- 3.25, - 3.09) mL/min/1.73 m²/year, and the decline was greater in patients with higher proteinuria categories. Advanced CKD stage and proteinuria were strongly associated with the risk of a ≥ 30% decrease in eGFR. According to the Cox analyses, CKD stages G3a, G3b, and G4 had hazard ratios (HRs) for poor renal outcomes of 1.89 (1.40-2.56), 3.84 (2.92-5.04), and 7.23 (5.51-9.50), respectively, and proteinuria categories A2 and A3 had HRs of 1.66 (1.43-1.93) and 2.02 (1.71-2.40), respectively. The CART analysis suggested that CKD G4 patients aged < 60 years, those aged 60-68 years with proteinuria, and CKD G3b patients aged < 54 years with proteinuria had higher risks of ≥ 30% eGFR decline. In conclusion, our study suggested the utility of a CKD heatmap and the importance of controlling the levels of proteinuria in ADPKD patients.