Re-exploration of the optimal threshold for restrictive transfusion after hip fracture: a multicenter prospective Cohort.

Background: Restrictive transfusion is recommended in patients undergoing hip fracture surgery. However, the evidence regarding the optimal threshold for transfusion remained uncertain.

Methods: In this multicenter prospective cohort, we enrolled participants who received surgical treatment of a hip fracture and were aged 65 years or older from 2017 to 2023. The restrictive transfusion of red blood cells (RBCs) with a threshold at hemoglobin level <8 g/dl was the standard of care during the study period. When periodic shortage of blood existed, the threshold was adjusted to <7 g/dl as a priori-defined coping strategy. The primary outcome was all-cause mortality within one year after surgery.

Results: In this study, 3516 and 732 patients received standard care (threshold at hemoglobin level <8 g/dl) and alternative care (threshold at hemoglobin level <7 g/dl), respectively. Patients in alternative care group had a similar incidence of death within one year compared with patients in standard care group (157 [17.6%] patients versus 575 [17.1%] patients), with an adjusted hazard ratio (HR) of 1.01 (95% confidence interval [CI] 0.85 to 1.21, P = 0 · 885). For subgroup analysis of patients with cardiovascular disease (CVD) at baseline, death occurred in 53 (27.5%) patients of alternative care group and 182 (19.9%) of standard care group, with an adjusted HR of 1.45 (95% CI 1.05 to 1.99, P = 0.023).

Conclusion: In patients without baseline CVD, adjusting the threshold for transfusion from the standard level (hemoglobin level <8 g/dl) to an alternative level (<7 g/dl) might be a safe practice in coping periodic blood shortage. In patients with baseline CVD, standard threshold remained recommended. Future randomized clinical trials were warranted by the current study.