Older people are prone to multiple chronic diseases and, as a result, require multiple medications. At present, there is no study to verify whether the use of high-risk perioperative medications (HRPOMs) will adversely affect postoperative outcomes in the relatively old patient. In this study, we aimed to analyze the risks of HRPOMs for prolonged length of hospital stay (LOS) in advanced-aged (≥ 75 years) patients undergoing spinal surgery.Medical records of advanced-aged patients who underwent spinal surgeries were retrospectively reviewed. Patients were divided into those who had prolonged LOS (≥ eight days) versus those who did not (< eight days). The demographics, medical comorbidities, and perioperative medications were analyzed. Univariate and multivariate regression were used to determine perioperative risk factors for prolonged LOS.A total of 268 patients were included with a median age of 79 years (interquartile range [IQR]=76, 82) and 127 (47.4%) patients had a prolonged LOS. In multivariate logistic analysis, higher body mass index (odds ratio [OR] = 1.116; 95% CI, 1.031-1.209), operation time (OR) = 1.009; 95% CI, 1.005-1.012), and number of postoperative HRPOMs (OR= 1.910; 95% CI, 1.464-2.492) were identified as independent predictors for prolonged LOS. The use of metformin was associated with lower likelihood of prolonged LOS in diabetic patients (OR = 0.365; 95% CI, 0.157-0.846).Our results indicate that the higher number of postoperative HRPOMs, rather than a specific HRPOMs type, is a risk factor for prolonged LOS. The continued preoperative use of metformin in patients with diabetes has a positive impact on the postoperative outcomes.© 2024 Author(s).