The Sequential Organ Failure Assessment (SOFA) score was developed to describe the morbidity of patients who are critically ill [1] and is still used widely. However, some of the original score constituents no longer align with contemporary critical care clinical practice. Proposals to update the score including the addition and/or update of SOFA score constituents are yet to be evaluated [2]. The aim of our study was to evaluate the impact of potential updates on the predictive accuracy of a modified SOFA (mSOFA) score.

This single-centre retrospective cohort study was conducted at Jichi Medical University Saitama Medical Center. This study was approved by the institutional review board. Patients aged ≥ 18 y who were admitted to the ICU and stayed for ≥ 24 h between August 2017 and July 2023 were included. Data on patient characteristics, clinical data to inform mSOFA calculations and survival outcomes were extracted from electronic medical records.

The additional mSOFA score constituents included: the use of high-flow nasal oxygenation (HFNO), non-invasive ventilation (NIV) and veno-venous extracorporeal membrane oxygenation (VV-ECMO) to the respiratory component; platelet transfusion to the coagulation component; vasopressin and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) to the cardiovascular component; renal replacement therapy (RRT) to the renal component; and lactate levels to a new, seventh, component.

The scoring for the new items was as follows: VV-ECMO, 4 points; NIV, minimum of 3 points assigned with 4 points if the ratio of partial pressure of oxygen in arterial blood to the fraction of inspiratory oxygen concentration (P/F) during use was < 100; HFNC, minimum of 2 points assigned, with 3 points if the P/F ratio was < 200 and 4 points if it was < 100; platelet transfusion, 4 points; vasopressin use, 4 points; VA-ECMO, 4 points; and RRT (in patients not on maintenance dialysis), 4 points. Lactate levels were scored as: < 2 mmol.l^-1, 0 points; 2–4 mmol.l^-1, 1 points; 4–6 mmol.l^-1, 2 points; 6–8 mmol.l^-1, 3 points; and ≥ 8 mmol.l^-1, 4 points. Scores were assigned to the new items based on their mortality rates and compared with the mortality rates of the original SOFA score items. The outcome was the area under the receiver operating characteristic curve (AUROC) for hospital mortality. The highest scores within 24 h of admission were defined as ‘admission SOFA’, and the highest scores during the ICU stay were defined as ‘max SOFA’ [3]. Analysis was performed using R (version 4.3.3, R Foundation, Vienna, Austria), and the DeLong test was used to compare the AUROCs. A two-sided test with a significance level of 5% was used.

Of the 9629 patients admitted, 6167 were included in the analysis (online Supporting Information Figure S1). Patient demographics are shown in Table 1. The distribution and mortality rates of each SOFA score component are shown in the online Supporting Information Figure S2. A comparison of the AUROCs between the original SOFA and mSOFA scores revealed statistically significant but clinically minimal differences for admission SOFA, and there was no difference for max SOFA. (Fig. 1 and online Supporting Information Table S1).

In this study, we have added widely used organ support measures, platelet transfusion, vasopressin and lactate levels to the original SOFA score but did not observe any meaningful improvement in predictive power for in-hospital mortality. This may be because many of the new items lacked fidelity due to a score assignment of 4 points, which is the maximum possible score for each organ score. Almost all patients who qualified for these new items were already receiving the highest score of 4 points in the original SOFA score (online Supporting Information Table S2), consequently leading to no additional improvement in predictive accuracy by the modification. These values were selected by the study team; further research is required to evaluate the relative importance of each variable in larger datasets. When updating the SOFA score, it seems important to adjust the clinical thresholds, such as the criteria based on vasopressor dosage, to align with the current clinical practices rather than simply adding new items. There have been several reports on modifying single components, which show improved predictive power primarily focused on the cardiovascular component, suggesting its critical role in the SOFA score update [4, 5]. These reports also indicate that adjusting clinical thresholds, rather than merely adding new items, can lead to more accurate predictions. Despite being a single-centre study and limitations due to its retrospective nature, the strengths of this study include its large sample size (n > 6000) with minimal missing data and its evaluation of new components following the SOFA score update proposal.

In conclusion, updating the SOFA score to include organ support, platelet transfusion and lactate levels did not significantly improve the predictive power for mortality using the current threshold settings.

序贯器官衰竭评估 （SOFA） 评分用于描述危重症患者的发病率 [1] ，至今仍被广泛使用。然而，一些原始评分成分不再与当代重症监护临床实践保持一致。更新评分的建议（包括增加和/或更新 SOFA 评分成分）尚未进行评估 [2]。我们研究的目的是评估潜在更新对改良 SOFA （mSOFA） 评分预测准确性的影响。

这项单中心回顾性队列研究在自治医科大学埼玉医学中心进行。这项研究得到了机构审查委员会的批准。纳入 2017 年 8 月至 2023 年 7 月期间入住 ICU 并住院 ≥ 24 h 的 ≥ 18 岁患者。从电子病历中提取有关患者特征、为 mSOFA 计算提供信息的临床数据和生存结果的数据。

其他 mSOFA 评分成分包括：对呼吸成分使用高流量鼻氧合 （HFNO）、无创通气 （NIV） 和静脉-静脉体外膜肺氧合 （VV-ECMO）;血小板输注到凝血成分;血管加压素和静脉动脉体外膜肺氧合 （VA-ECMO） 作用于心血管成分;肾脏成分的肾脏替代疗法 （RRT）;和乳酸水平达到新的第七个组成部分。

新项目的评分如下： VV-ECMO，4 分;NIV，如果动脉血氧分压与使用过程中吸气氧浓度 （P/F） 分数的比值为 < 100，则至少分配 3 分，分配 4 分;HFNC，至少分配 2 分，如果 P/F 比率为 < 200，则为 3 分，如果为 < 100，则为 4 分;血小板输注 4 分;使用加压素，4 分;VA-ECMO，4 分;和 RRT （未接受维持透析的患者），4 分。乳酸水平评分为： < 2 ^mmol.l-1,0 分;2–4 ^mmol.l-1,1 分;4–6 ^mmol.l-1,2 分;6–8 ^mmol.l-1,3 分;≥ 8 ^mmol.l-1,4 分。根据新项目的死亡率分配分数，并与原始 SOFA 评分项目的死亡率进行比较。结局是医院死亡率的受试者工作特征曲线下面积 （AUROC）。入院后 24 小时内的最高分数被定义为“入院 SOFA”，ICU 住院期间的最高分数被定义为“最大 SOFA”[3]。使用 R （Version 4.3.3， R Foundation， Vienna， Austria） 进行分析，并使用 DeLong 检验比较 AUROCs。使用显著性水平为 5% 的双侧检验。

在收治的 9629 名患者中，包括 6167 名被纳入分析（在线支持信息图 S1）。患者人口统计数据如表 1 所示。每个 SOFA 评分组成部分的分布和死亡率显示在在线支持信息图 S2 中。原始 SOFA 和 mSOFA 评分之间的 AUROCs 比较显示，入院 SOFA 差异有统计学意义，但临床差异最小，最大 SOFA 没有差异。（图 1 和在线支持信息表 S1）。

在这项研究中，我们在原始 SOFA 评分中添加了广泛使用的器官支持措施、血小板输注、加压素和乳酸水平，但没有观察到对院内死亡率的预测能力有任何有意义的改善。这可能是因为许多新项目由于分配了 4 分的乐谱而缺乏保真度，这是每个器官乐谱的最高可能分数。几乎所有符合这些新项目条件的患者都已经在原始 SOFA 评分（在线支持信息表 S2）中获得了 4 分的最高分，因此修改后预测准确性没有进一步提高。这些值是由研究小组选择的;需要进一步的研究来评估每个变量在更大数据集中的相对重要性。在更新 SOFA 评分时，调整临床阈值（例如基于血管加压药剂量的标准）以符合当前的临床实践似乎很重要，而不是简单地添加新项目。有几篇关于修饰单个成分的报告显示，主要集中在心血管成分的预测能力提高，表明它在 SOFA 评分更新中起关键作用 [4， 5]。这些报告还表明，调整临床阈值，而不仅仅是添加新项目，可以带来更准确的预测。尽管是一项单中心研究，并且由于其回顾性而存在局限性，但这项研究的优势在于其样本量大 （n > 6000） 和最少的缺失数据，以及根据 SOFA 评分更新提案对新组成部分的评估。

总之，使用当前阈值设置更新 SOFA 评分以包括器官支持、血小板输注和乳酸水平并未显著提高对死亡率的预测能力。