Objectives. Lower respiratory tract infection (LRTI) in the octogenarian population is a highly prevalent disorder associated with increased mortality rates. Anemia is a common disorder in older adults and is often left untreated. We investigated whether anemia was a risk factor for LRTI-caused readmission and death in octogenarian patients. Design. A retrospective cohort study was designed. Participants. Old patients (age: >= 80 years) hospitalized at the Department of Geriatrics to undergo treatment for LRTIs were included. A total of 215 patients (mean age: 88.73 years; 77.2% men) were studied. The patients were divided into two groups (anemia and non-anemia) based on the hemoglobin level. They were followed up for 1 year after discharge or until mortality event. The primary follow-up outcome was LRTI-caused readmission and/or death. Results. The risk of readmission due to LTRI within 1 year of discharge was 2.308 times higher in the anemia group than the risk for the non-anemia group. The number of patients experiencing >= 2 readmissions in the anemia group was significantly higher than that in the non-anemia group (35 (23.5%) vs. 2 (3%), P < 0.001). To prevent readmission of one case, only 2.65 cases with anemia needed to be treated. Furthermore, the risk of LRTI-related deaths was 6.644 times higher in the anemia group than the risk for the non-anemia group. To prevent death of one case, only 3.9 cases with anemia needed to be treated. Statistic results revealed that hemoglobin was an independent protective factor for LRTI-caused readmission (logistic regression method, OR, 0.969; 95% CI, 0.950-0.989) and deaths (Cox regression method, beta -0.037, HR, 0.964; 95% CI, 0.934-0.994). Conclusions. Anemia is a widely prevalent and relevant risk factor associated with LRTI-caused readmission and death within 1 year of discharge in octogenarian patients. Trial Registration. This trial is registered with NCT05355324.