Anesthesiology. 2021 Apr 1;134(4):577-587. doi: 10.1097/ALN.0000000000003699.
Preoperative frailty is strongly associated with postoperative complications and mortality. However, the pathways between frailty, postoperative complications, and mortality are poorly described. The authors hypothesized that the occurrence of postoperative complications would mediate a substantial proportion of the total effect of frailty on mortality after elective noncardiac surgery.
Following protocol registration, the authors conducted a retrospective cohort study of intermediate- to high-risk elective noncardiac surgery patients (2016) using National Surgical Quality Improvement Program data. The authors conducted Bayesian mediation analysis of the relationship between preoperative frailty (exposure, using the Risk Analysis Index), serious complications (mediator), and 30-day mortality (outcome), comprehensively adjusting for confounders. The authors estimated the total effect of frailty on mortality (composed of the indirect effect mediated by complications and the remaining direct effect of frailty) and estimated the proportion of the frailty-mortality association mediated by complications.
The authors identified 205,051 patients; 1,474 (0.7%) died. Complications occurred in 20,211 (9.9%). A 2 SD increase in frailty score resulted in a total association with mortality equal to an odds ratio of 3.79 (95% credible interval, 2.48 to 5.64), resulting from a direct association (odds ratio, 1.76; 95% credible interval, 1.34 to 2.30) and an indirect association mediated by complications (odds ratio, 2.15; 95% credible interval, 1.58 to 2.96). Complications mediated 57.3% (95% credible interval, 40.8 to 73.8) of the frailty-mortality association. Cardiopulmonary complications were the strongest mediators among complication subtypes.
Complications mediate more than half of the association between frailty and postoperative mortality in elective noncardiac surgery.
术前虚弱与术后并发症和死亡率密切相关。然而，虚弱、术后并发症和死亡率之间的关系描述得很差。作者假设术后并发症的发生将在很大程度上解释虚弱对择期非心脏手术后死亡率的总影响。
在方案注册后，作者使用国家手术质量改进计划的数据对中高危择期非心脏手术患者（2016 年）进行了回顾性队列研究。作者对术前虚弱（暴露，使用风险分析指数）、严重并发症（中介）和 30 天死亡率（结局）之间的关系进行了贝叶斯中介分析，全面调整了混杂因素。作者估计了虚弱对死亡率的总影响（由并发症介导的间接效应和虚弱的剩余直接效应组成），并估计了并发症介导的虚弱-死亡率关联的比例。
作者确定了 205051 名患者；1474 名（0.7%）死亡。20211 例（9.9%）发生并发症。虚弱评分增加 2 个标准差与死亡率总相关，其比值比为 3.79（95%可信区间，2.48 至 5.64），这是由直接关联（比值比，1.76；95%可信区间，1.34 至 2.30）和并发症介导的间接关联（比值比，2.15；95%可信区间，1.58 至 2.96）共同作用的结果。并发症介导了虚弱与术后死亡率之间 57.3%（95%可信区间，40.8 至 73.8）的关联。心肺并发症是并发症亚型中最强的中介。
在择期非心脏手术中，并发症介导了虚弱与术后死亡率之间超过一半的关联。
