SACrA score to predict the initiation of renal replacement therapy in critically ill patients: a single-center retrospective study

Acute kidney injury (AKI) is a prevalent complication in critically ill patients that affects the timing of renal replacement therapy (RRT) initiation. This study aimed to develop and validate the SACrA score for predicting non-emergent initiations (BUN ≥112 mg/dL or oliguria for >72 h) of RRT in critically ill patients. We conducted a retrospective cohort study using data from two cohorts. The derivation cohort included patients admitted to the ICU between November 2021 and December 2023, whereas the validation cohort included patients admitted between September 2019 and October 2021. The primary outcome was non-emergent RRT initiation. The multivariate logistic regression with stepwise selection based on the Akaike information criterion finalized the model, including the variables, such as sex, albumin (Alb), creatinine (Cr), and APACHE II score (SACrA). The derivation and validation cohorts comprised 470 and 476 patients, respectively. The SACrA score showed a strong predictive performance for non-emergent RRT initiation in both the cohorts. Cohort 1 had an ROC–AUC of 0.971, with a calibration slope of 0.982 and an intercept of 0.009, whereas cohort 2 had an ROC–AUC of 0.918, with a calibration slope of 0.988 and an intercept of 0.004. The SACrA score is a robust tool for predicting non-emergent RRT initiation in critically ill patients using readily available clinical variables. Though additional data are needed to validate the SACrA score, our analysis suggests the tool may help clinicians make informed decisions, reduce unnecessary RRT, and thereby improve patient outcomes.

急性肾损伤（Acute kidney injury, AKI）是重症患者中高发的并发症，可影响肾脏替代治疗（Renal replacement therapy, RRT）的启动时机。本研究旨在开发并验证SACrA评分，用于预测重症患者的非紧急肾脏替代治疗启动，其指征为血尿素氮（BUN）≥112mg/dL或少尿持续时长＞72小时。我们采用两个队列的数据开展回顾性队列研究：推导队列纳入2021年11月至2023年12月期间入住重症监护病房（ICU）的患者，验证队列则纳入2019年9月至2021年10月期间入住的患者。本研究的主要结局为非紧急RRT启动。本研究基于赤池信息准则（Akaike Information Criterion, AIC）通过逐步变量选择法构建多因素logistic回归模型，最终纳入性别、白蛋白（Albumin, Alb）、肌酐（Creatinine, Cr）及急性生理学与慢性健康状况评分系统II（APACHE II）评分等变量，形成SACrA评分。推导队列与验证队列分别纳入470例和476例患者。SACrA评分在两个队列中均展现出优异的非紧急RRT启动预测性能：队列1的ROC-AUC为0.971，校正斜率为0.982，截距为0.009；队列2的ROC-AUC为0.918，校正斜率为0.988，截距为0.004。SACrA评分是一款基于易得临床常规变量、可用于预测重症患者非紧急RRT启动的稳健工具。尽管尚需更多数据验证SACrA评分，但本研究分析表明该工具可协助临床医师做出合理决策，减少不必要的肾脏替代治疗，进而改善患者预后。