The association between preoperative modified frailty index and postoperative complications in Chinese elderly patients with hip fractures

OBJECTIVES: To investigate the role of a preoperative modified frailty index (mFI) based on data from medical records in predicting postoperative complications among older Chinese patients with hip fractures. METHODS: This retrospective cohort study included consecutive older patients with hip fracture admitted to the Department of Orthopaedics, West China Hospital, Sichuan University, from December 2010 to June 2017 who underwent surgical repair. We selected 33 variables, including characteristics of hip fracture, to construct a mFI. Each variable was coded with a value of 0 when a deficit was absent or 1 when it was present. We calculated the mFI as the proportion of positive items and defined frailty as mFI value greater than or equal to 0.21 according to threshold proposed by Hoover et al. We examined the relationship between mFI and severity of postoperative complications and the occurrence of in-hospital pneumonia including statistical adjustment for several demographics (e.g. age, gender, and marital status) and habits (smoking and alcohol intake), time from fracture to surgery in the multivariable model. RESULTS: We included 965 patients (34% male; mean age: 76.77 years; range: 60 to 100 years) with a prevalence of frailty of 13.06%. The presence of frailty was associated with a higher severity of complications (OR: 2.07; 95% CI: 1.40 to 3.05). Frail patients were more likely to develop in-hospital pneumonia than non-frail patients (OR: 2.08; 95% CI: 1.28 to 3.39). CONCLUSION: The preoperative modified frailty index based on data from medical records proved significantly associated with postoperative complications among older patients with hip fractures undergoing hip surgery. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12877-021-02330-7.