Performance And Agreement Of Risk Stratification Instruments For Postoperative Delirium In Persons Aged 50 Years Or Older

Several risk stratification instruments for postoperative delirium in older people have been developed because early interventions may prevent delirium. We investigated the performance and agreement of nine commonly used risk stratification instruments in an independent validation cohort of consecutive elective and emergency surgical patients aged ≥50 years with ≥1 risk factor for postoperative delirium. Data was collected prospectively. Delirium was diagnosed according to DSM-IV-TR criteria. The observed incidence of postoperative delirium was calculated per risk score per risk stratification instrument. In addition, the risk stratification instruments were compared in terms of area under the receiver operating characteristic (ROC) curve (AUC), and positive and negative predictive value. Finally, the positive agreement between the risk stratification instruments was calculated. When data required for an exact implementation of the original risk stratification instruments was not available, we used alternative data that was comparable. The study population included 292 patients: 60% men; mean age (SD), 66 (8) years; 90% elective surgery. The incidence of postoperative delirium was 9%. The maximum observed incidence per risk score was 50% (95%CI, 15–85%); for eight risk stratification instruments, the maximum observed incidence per risk score was ≤25%. The AUC (95%CI) for the risk stratification instruments varied between 0.50 (0.36–0.64) and 0.66 (0.48–0.83). No AUC was statistically significant from 0.50 (p≥0.11). Positive predictive values of the risk stratification instruments varied between 0–25%, negative predictive values between 89–95%. Positive agreement varied between 0–66%. No risk stratification instrument showed clearly superior performance. In conclusion, in this independent validation cohort, the performance and agreement of commonly used risk stratification instruments for postoperative delirium was poor. Although some caution is needed because the risk stratification instruments were not implemented exactly as described in the original studies, we think that their usefulness in clinical practice can be questioned.鉴于早期干预可预防术后谵妄（postoperative delirium），目前已针对老年患者开发出多款风险分层工具（risk stratification instruments）。本研究在一个独立验证队列中，对9种常用的术后谵妄风险分层工具的表现与一致性进行了评估；该队列纳入连续招募的、年龄≥50岁且至少存在1项术后谵妄危险因素的择期与急诊手术患者，数据为前瞻性收集。 谵妄的诊断依据《精神障碍诊断与统计手册第四版修订版》（Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision, DSM-IV-TR）标准。本研究针对每种风险分层工具的各风险评分，计算了术后谵妄的实际发生率。此外，我们通过受试者工作特征曲线（Receiver Operating Characteristic curve, ROC）的曲线下面积（Area Under the Curve, AUC）、阳性预测值与阴性预测值，对各风险分层工具进行了比较，并最终计算了各工具间的阳性一致性。 当无法获取原始风险分层工具精确实施所需的数据时，本研究采用了具备可比性的替代数据。本研究共纳入292例患者，其中男性占60%，平均年龄（标准差）为66（8）岁，90%的患者接受择期手术。术后谵妄的总体发生率为9%。各风险评分对应的最高实际发生率为50%（95%置信区间：15%~85%）；其中8种风险分层工具的各风险评分最高实际发生率≤25%。 各风险分层工具的AUC（95%置信区间）介于0.50（0.36~0.64）至0.66（0.48~0.83）之间，所有AUC均未与0.50存在统计学显著性差异（p≥0.11）。各风险分层工具的阳性预测值介于0~25%之间，阴性预测值介于89%~95%之间；阳性一致性介于0~66%之间。未观察到某一款风险分层工具的表现显著优于其他工具。 综上，在本独立验证队列中，常用的术后谵妄风险分层工具的表现与一致性均较差。尽管由于各工具未完全按照原始研究中的方案实施，本研究结论需谨慎解读，但我们认为这类工具在临床实践中的实用性值得商榷。