Distinct Hemoglobin Trajectories and Their Prognostic Implications in Chronic Kidney Disease: Findings from the KNOW-CKD Cohort

Objectives : Anemia is a common comorbidity in patients with chronic kidney disease (CKD) and has been associated with adverse kidney and cardiovascular outcomes. However, longitudinal patterns of hemoglobin (Hb) change and their prognostic implications remain unclear. We aimed to identify distinct Hb trajectories and evaluate their associations with clinical outcomes in CKD.
Methods : We analyzed 1,940 adults with CKD from a prospective cohort, applying group-based trajectory modeling (GBTM) to repeated Hb measurements. The primary endpoint was a composite kidney outcome (≥50% decline in eGFR, doubling of serum creatinine, initiation of dialysis, or kidney transplantation). Secondary endpoints were cardiovascular events and all-cause mortality.
Results : GBTM identified four distinct Hb trajectories: high, moderately high, intermediate, and low. Compared with the intermediate trajectory, the high group showed substantially lower risk of the composite kidney outcome (hazard ratio [HR] 0.210, 95% confidence interval [CI] 0.125–0.353), the moderately high group showed comparable risk (HR 0.766, 95% CI 0.555–1.058), and the low group had higher risk (HR 1.595, 95% CI 1.186–2.145). No significant associations were observed with cardiovascular events or all-cause mortality after full adjustment.
Conclusions : Distinct Hb trajectories were strongly associated with kidney outcomes in CKD. Sustained higher Hb trajectories conferred favorable renal prognosis, whereas persistently low trajectories predicted adverse outcomes. Beyond static Hb values, trajectory-based assessment may provide a novel framework for individualized risk stratification and anemia management in CKD.