Association between dementia and postoperative complications after hip fracture surgery in the elderly: analysis of 87,654 patients using a national administrative database

Introduction: Mortality following hip fracture surgery is higher in patients with dementia than those without; however, few large-scale studies have investigated postoperative in-hospital complications in such patients. The aim of this study was to elucidate the complications that occur after hip fracture surgery in patients with and without dementia using a large national database. Materials and methods: We retrospectively identified patients aged ≥70 years who underwent hemiarthroplasty, osteosynthesis for femoral neck fracture or osteosynthesis for intertrochanteric fracture, and compared the occurrence of postoperative complications between patients with and without dementia. Multivariate logistic regression analysis was performed to adjust for patient characteristics and hospital factors. Results: A total of 87,654 patients were included in this study, including 9419 with dementia. Compared with the non-dementia group, the dementia group showed a higher incidence of overall postoperative complications [odds ratio (OR) 1.45; p < 0.001), surgical site infection (OR 1.58; p = 0.004), urinary tract infection (OR 1.87; p < 0.001) and respiratory complications (OR 1.49; p < 0.001). The rate of postoperative complications was higher for all types of hip fracture surgery. The occurrence of a postoperative complication was significantly higher in patients aged ≥80 years (OR 1.37; p < 0.001) and those with dementia (OR 1.45; p < 0.001), any type of malignancy (OR 1.42; p < 0.001), a history of cardiovascular disease (OR 1.33; p < 0.001), a history of cerebrovascular disease (OR 1.15; p = 0.029), chronic renal failure (OR 1.36; p < 0.001), liver cirrhosis (OR 1.41; p < 0.001) or blood transfusion after surgery (OR 1.49; p < 0.001). Conclusions: Our results highlight the need to pay particular attention to surgical site infection, urinary tract infection and respiratory complications in patients with preoperative dementia after hip fracture surgery. These results provide additional useful evidence to inform the management of these patients.