Incidence, Causes, and Risk Factors of Unplanned Readmissions in Elderly Patients Undergoing Hip Fracture Surgery: An Observational Study

Aim: The purpose of this study was to examine the incidence and cause of unplanned readmission after Surgically Treated Hip Fractures in Elderly Patients and identify the associated risk factors. Methods: This study retrospectively collected the data on elderly patients who underwent hip fracture surgery at two institutions from January 2020 to December 2021, and identified those who were readmitted within 12 months postoperatively. Based on the presence or not of postoperative readmission, they were divided into readmission and non-readmission groups. Demographics, surgery-related variables, and laboratory parameters were compared between groups. The specific causes for documented readmission were collected and summarized. Multivariate logistic regression analysis was performed to identify the associated risk factors. Results: There were 930 patients including 76 (8.2%) patients who were readmitted within 12 months postoperatively. Overall, cardiac and respiratory complications and new-onset fractures were the first three common causes of readmission, taking an overwhelming proportion of 53.9% (41/76). Over 60% (61.8%, 47/76) of readmissions occurred within 30 days after surgery, with medical complications taking a predominance (89.4%, 42/47). New-onset fractures accounted for a proportion of 18.4% (14/76), occurring at different time points; especially, at 90-365 days, it accounted for 44.4% (8/18). Multivariate analysis revealed that age >= 80 years (OR, 1.0, 95% CI, 1.0 to 1.1; P=0.032), preoperative albumin level <= 21.5 g/L (OR, 1.1, 95% CI, 1.0 to 1.2; P=0.009), the postoperative occurrence of DVT (OR, 4.2, 95% CI, 2.5 to 7.2; P=0.001), and local anesthesia (OR, 2.1, 95% CI, 1.1 to 4.0; P=0.029) were independent risk factors for unplanned readmissions. Conclusion: This study identified several risk factors for unplanned readmissions after elderly hip fractures, and provided detailed information about unplanned readmissions.