BACKGROUND Preoperative anaemia and red blood cell (RBC) transfusions are associated with poorer clinical outcomes. It is unknown whether perioperative RBC transfusions mediate the relationship between preoperative haemoglobin levels and postoperative outcomes. METHODS This was a prospective observational study among patients aged ≥50 yr undergoing elective major noncardiac surgery from four Swedish hospitals. The co-primary outcomes were 1-yr major adverse cardiovascular and cerebrovascular events (MACCEs) and all-cause mortality. The secondary outcome was a composite of 30-day mortality, MACCEs, acute kidney injury (AKI), pulmonary embolism, anastomotic leak, and postoperative infection. Mediation analyses were conducted with preoperative haemoglobin as the exposure and RBC transfusion as a mediator. RESULTS Among 1060 patients (mean age 70 [SD 9] yr; 472 [45%] women), 171 patients (16.1%) developed 1-yr MACCEs, and 105 patients (9.9%) died within 1 yr. Preoperative haemoglobin levels were significantly associated with both 1-yr MACCEs (b=-0.015, P=0.041) and all-cause mortality (b=-0.028, P<0.001). Volume of RBC transfusion was not directly associated with the outcomes and did not mediate the relationship between preoperative haemoglobin levels and 1-yr MACCEs (b=-0.001, P=0.451) or all-cause mortality (b=-0.002, P=0.293). For the secondary outcome, RBC transfusions had a significant mediating effect between preoperative haemoglobin and the composite 30-day outcome; however, no direct association was observed (b=0.006, P=0.554). CONCLUSIONS Preoperative haemoglobin levels were significantly associated with 1-yr MACCEs and all-cause mortality. This effect was not mediated by perioperative RBC transfusions. Further research is needed to confirm these findings.

中文翻译：

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围手术期输血对术前血红蛋白水平的影响是非心脏大手术患者长期结局的危险因素：一项前瞻性多中心观察研究。


背景 术前贫血和红细胞 （RBC） 输注与较差的临床结局相关。目前尚不清楚围手术期红细胞输注是否介导术前血红蛋白水平与术后结局之间的关系。方法 这是一项前瞻性观察研究，对象为来自 4 家瑞典医院的 ≥50 岁接受择期非心脏手术的患者。共同主要结局是 1 年主要不良心脑血管事件 （MACCEs） 和全因死亡率。次要结局是 30 天死亡率、 MACCEs 、急性肾损伤 （AKI） 、肺栓塞、吻合口瘘和术后感染的复合结局。以术前血红蛋白暴露，红细胞输注为介质进行中介分析。结果 在 1060 例患者 （平均年龄 70 [SD 9] 岁;472 例 [45%] 女性） 中，171 例患者 （16.1%） 发生 1 年 MACCEs，105 例患者 （9.9%） 在 1 年内死亡。术前血红蛋白水平与 1 年 MACCE （b=-0.015，P=0.041） 和全因死亡率 （b=-0.028，P<0.001） 显著相关。红细胞输注量与结局没有直接关系，也不介导术前血红蛋白水平与 1 年 MACCE （b=-0.001，P=0.451） 或全因死亡率 （b=-0.002，P=0.293） 之间的关系。对于次要结局，红细胞输注在术前血红蛋白和复合 30 天结局之间具有显着的中介作用;然而，未观察到直接关联 （b=0.006，P=0.554）。结论 术前血红蛋白水平与 1 年 MACCEs 和全因死亡率显著相关。这种影响不是由围手术期 RBC 输注介导的。需要进一步的研究来证实这些发现。