Time to surgery and 30-day mortality after hip fracture: An observational study of 29,695 patients reported to the Spanish National Hip Fracture Registry (SNHFR)

Introduction: The aim of this study was to investigate the effect of time to surgery (TTS) on 30-day mortality in a cohort of patients from the Spanish National Hip Fracture Registry (SNHFR). Methods: Retrospective study of a prospective database of hip fracture patients >= 75 years old between 2017 and 2019. Exclusion criterion was nonsurgical treatment. Association between TTS and 30-day mortality was assessed with a univariate analysis. Effect size was calculated using the probability of superiority. Regression analysis was performed to analyze the relationship between TTS and 30-day vital status. The ROC curve was used to evaluate the discrimination of mortality based on TTS. Results: A total of 29,695 patients met the inclusion criteria. The median TTS was 53.8 h. Surgery within 48 h was performed in 51.8 % of cases. Patients with delay of surgery more than 2 days rather than within 2 days were more likely to present an ASA score above 2 (58.9 % vs. 41.1 %, p < 0.001), less likely to achieve postoperative mobilization within 24 h (63 % vs. 67.4%, p < 0.001), more likely to develop pressure ulcers (10.7% vs. 6.9%, p < 0.001), and had longer length of stay (10.7 days vs. 6.9 days, p < 0.001). The overall 30-day mortality rate was 7.8 %. Median TTS was significantly higher in decedents (66 h) than in survivors (56.5 h). There were higher statistically significant differences in 30-day mortality between patients who underwent surgery after 2 days (7.5 %) and those who underwent surgery within 2 days (5.4 %). The 30-day mortality was 5.2 % in patients operated within 24 h and 9.2 % in patients operated more than 120 h. Probability of superiority value was 0.44. Area under the curve reached a value of 0.55. Conclusions: The associations between TTS and 30-day mortality were weak. Hip fracture surgery performed within 2 days was significantly associated with remobilization on the day after the hip fracture, with fewer postoperative pressure ulcers and shorter hospital stays. Despite the weakness of the TTS and 30-day mortality association, there are benefits to consider if surgery is performed within 2 days. Our results suggest that patients should be fit for surgery as soon as possible.