Objective : To explore the optimal cut-off values of systemic immune-inflammation index (SII) and hypersensitive C-reactive protein to albumin ratio (HCAR) in predicting the poor prognosis of chronic kidney disease (CKD) in different age groups. Methods : A retrospective analysis of 80 patients with CKD admitted to our hospital from January 2024 to December 2024 was divided into a good prognosis group and a poor prognosis group. The patients with poor prognosis were divided into < 60 years old group and ≧ 60 years old group. The changes of SII and HCAR in patients were observed, and the predictive value of SII combined with HCAR on the poor prognosis of CKD in different age groups was evaluated.Results : The levels of SII and HCAR in the poor prognosis group were higher than those in the good prognosis group (P< 0.05). The patients with poor prognosis in the ≥ 60 years old group were higher than those in the < 60 years old group (P< 0.05). Elevated SII and HCAR levels were risk factors for poor prognosis of CKD in different age groups (P< 0.05). The area under the curve of SII and HCAR levels in predicting the poor prognosis of CKD in different age groups was 0.661 and 0.649, respectively, and the AUC of combined prediction was 0.773. The difference in the area under the curve was statistically significant (P< 0.05). The Youden index was 0.325 and 0.350, respectively. Conclusion : SII combined with HCAR can predict the poor prognosis of CKD in different age groups, and the level is increased in CKD with poor prognosis in older age.