Association of Anemia (Hemoglobin <13 g/dL in Men and <12 g/dL in Women) with Long-Term Kidney Prognosis in Patients with ADPKD: Insights from Time Series Analyses

Background: Hemoglobin (Hb) levels are generally higher in autosomal dominant polycystic kidney disease (ADPKD) compared to other kidney diseases, but the prognostic role of anemia in ADPKD is not well understood. Prognostic factors for kidney outcomes can vary with the length of follow-up periods, making it crucial to understand the time-series changes and integrals of pseudo-R2 values for kidney risk factors. Methods: We enrolled 553 ADPKD patients. Renal outcome was defined as a 50% reduction in estimated glomerular filtration rate or initiation of renal replacement therapy. Survival analyses and logistic regression analyses for generating time-series pseudo-R2 values were conducted. The integrated values of the pseudo-R2 values from the 1st year to the 17th year (1Y–17Y Integrals) were calculated to determine the optimal Hb cut-off points for long-term renal prognosis. Results: Multivariable Cox analyses indicated that anemia (Hb 1 g/L decrease, P=0.0004) was associated with kidney disease progression. To determine the anemia cut-off for kidney prognosis, pseudo-R2 values for Hb <12 g/dL showed the highest 1Y–17Y integrals of 1.88 among all anemia cut-offs. These values peaked at 0.2401 two years after baseline and had the highest end value of 0.0721 at 17 years. Therefore, Hb <12 g/dL was identified as a key indicator of long-term kidney prognosis in ADPKD patients. Similar sex-specific analyses revealed different anemia cut-offs: Hb <13 g/dL in men and Hb <12 g/dL in women. Conclusion: The 1Y–17Y Integrals of the pseudo-R2 values for kidney prognosis contributed to determining the cut-off points of the anemia according to the sex difference. Funding: Government Support – Non-U.S.