SummaryBackgroundAnaemia following major surgery may be associated with unplanned readmission to hospital. However, the severity‐response relationship between the degree of anaemia at discharge and the risk of unplanned readmission is poorly defined. We aimed to describe the severity‐response relationship between haemoglobin concentration at the time of discharge and the risk of unplanned readmission in a cohort of patients undergoing different types of major surgery.MethodsWe performed a retrospective cohort study in a single tertiary health service, including all patients who underwent major surgery (orthopaedic, abdominal, cardiac or thoracic) between 1 May 2011 and 1 February 2022. The primary outcome was unplanned readmission to hospital in the 90 days following discharge after the index surgical procedure. These complex, non‐linear relationships were modelled with restricted cubic splines.ResultsWe identified 22,134 patients and included 14,635 in the primary analysis, of whom 1804 (12%) experienced at least one unplanned readmission. The odds of unplanned readmission rose when the discharge haemoglobin concentration was < 100 g.l‐1 (p < 0.001). On subgroup analysis, the haemoglobin threshold below which odds of readmission began to increase appeared to be higher in patients undergoing emergency surgery (110 g.l‐1; p < 0.001) compared with elective surgery. Declining discharge haemoglobin concentration was associated with increased odds ratios (95%CI) of unplanned readmission in patients undergoing orthopaedic (1.08 (1.01–1.15), p = 0.03), abdominal (1.13 (1.07–1.19), p < 0.001) and thoracic (1.12 (1.01–1.24), p = 0.03) procedures, but not cardiac surgery (1.09 (0.99–1.19), p = 0.07).ConclusionsOur findings suggest that a haemoglobin concentration < 100 g.l‐1 following elective procedures and < 110 g.l‐1 following emergency procedures, at the time of hospital discharge after major surgery, was associated with unplanned readmission. Future interventional trials that aim to treat postoperative anaemia and reduce unplanned readmission should include patients with discharge haemoglobin below these thresholds.

中文翻译：

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术后贫血与大手术后意外再入院之间的关联：一项回顾性队列研究†

摘要背景大手术后贫血可能与意外再次入院有关。然而，出院时贫血程度与计划外再入院风险之间的严重程度-反应关系尚不清楚。我们的目的是描述接受不同类型大手术的患者队列中出院时血红蛋白浓度与计划外再入院风险之间的严重程度-反应关系。方法我们在一个三级卫生服务机构中进行了一项回顾性队列研究，包括所有2011年5月1日至2022年2月1日期间接受过大手术（骨科、腹部、心脏或胸部）的患者。主要结局是在指数外科手术后出院后90天内意外再次入院。这些复杂的非线性关系使用受限三次样条进行建模。结果我们确定了 22,134 名患者，并在初步分析中纳入了 14,635 名患者，其中 1804 名患者 (12%) 经历了至少一次意外再入院。当出院血红蛋白浓度<100g时，非计划再入院的几率增加‐1（p < 0.001）。在亚组分析中，接受紧急手术的患者的血红蛋白阈值似乎更高（低于该阈值，再入院的几率开始增加）（110g‐1; p < 0.001）与择期手术相比。出院血红蛋白浓度下降与接受骨科手术 (1.08 (1.01–1.15), p = 0.03)、腹部手术 (1.13 (1.07–1.19), p < 0.001) 和胸部手术的患者意外再入院的比值比 (95%CI) 增加相关(1.12 (1.01–1.24), p = 0.03) 手术，但不是心脏手术 (1.09 (0.99–1.19), p = 0.07)。结论我们的研究结果表明血红蛋白浓度 < 100 g‐1遵循选择性程序且 < 110 升‐1紧急手术后、大手术后出院时的情况与计划外的再入院有关。未来旨在治疗术后贫血和减少计划外再入院的干预试验应包括出院血红蛋白低于这些阈值的患者。