This study aims to explore the connections between risk factors and clinical outcomes in octogenarian patients diagnosed with adult degenerative scoliosis (ADS). A total of 394 patients participated in this study, with 206 individuals in the younger group and 188 in the octogenarian group. We meticulously gathered patient demographics, including basic information, comorbidities, radiographic data, clinical scoring systems, and details on medical and surgical complications as well as revision surgeries. Univariable linear regression analysis revealed positive correlations between age and several postoperative outcomes: Sagittal vertical axis (SVA) (B = -0.572, P = 0.001), Oswestry Disability Index (ODI) (B = 0.145, P < 0.001), and Japanese Orthopaedic Association (JOA) score (B = 0.035, P < 0.001). Additionally, a positive relationship was observed between age and both proximal junctional kyphosis (PJK) (B = 0.055, P = 0.039) and internal fixation loosening (B = 0.253, P < 0.001). Receiver operator characteristic (ROC) curve analysis indicated that the age threshold values for predicting PJK and internal fixation loosening were 71.5 and 79.5, respectively. In octogenarian patients with ADS, the cost associated with spinal deformity surgery is accompanied by a greater incidence of surgical complications. Compared to younger patients, surgical intervention tends to be more effective at enhancing objective motor functions while having a lesser impact on the subjective experiences of octogenarian patients.