Inouye S K, Charpentier P A
Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06504, USA.
JAMA. 1996 Mar 20;275(11):852-7.
To prospectively develop and validate a predictive model for delirium based on precipitating factors during hospitalization, and to examine the interrelationship of precipitating factors and baseline vulnerability.
Two prospective cohort studies, in tandem.
General medical wards, university teaching hospital.
For the development cohort, 196 patients aged 70 years and older with no delirium at baseline, and for the validation cohort, 312 comparable patients.
New-onset delirium by hospital day 9, defined by the Confusion Assessment Method diagnostic criteria.
Delirium developed in 35 patients (18%) in the development cohort. Five independent precipitating factors for delirium were identified; use of physical restraints (adjusted relative risk [RR], 4.4; 95% confidence interval [CI], 2.5 to 7.9), malnutrition (RR, 4.0; 95% CI, 2.2 to 7.4), more than three medications added (RR, 2.9; 95% CI, 1.6 to 5.4), use of bladder catheter (RR, 2.4; 95% CI, 1.2 to 4.7), and any iatrogenic event (RR, 1.9; 95% CI, 1.1 to 3.2). Each precipitating factor preceded the onset of delirium by more than 24 hours. A risk stratification system was developed by adding 1 point for each factor present. Rates of delirium for low-risk (0 points), intermediate-risk (1 to 2 points), and high-risk groups (> or equal to 3 points) were 3%, 20%, and 59%, respectively (P < .001). The corresponding rates in the validation cohort, in which 47 patients (15%) developed delirium, were 4%, 20%, and 35%, respectively (P < .001). When precipitating and baseline factors were analyzed in cross-stratified format, delirium rates increased progressively from low-risk to high-risk groups in all directions (double-gradient phenomenon). The contributions of baseline and precipitating factors were documented to be independent and statistically significant.
A simple predictive model based on the presence of five precipitating factors can be used to identify elderly medical patients at high risk for delirium. Precipitating and baseline vulnerability factors are highly interrelated and contribute to delirium in independent substantive, and cumulative ways.
前瞻性地开发并验证基于住院期间诱发因素的谵妄预测模型，并研究诱发因素与基线脆弱性之间的相互关系。
两项串联的前瞻性队列研究。
大学教学医院的普通内科病房。
对于开发队列，选取196例70岁及以上且基线时无谵妄的患者；对于验证队列，选取312例类似患者。
根据《意识错乱评估法》诊断标准，在住院第9天时新发谵妄情况。
开发队列中有35例患者（18%）发生谵妄。确定了谵妄的5个独立诱发因素；使用身体约束（调整后相对危险度[RR]，4.4；95%置信区间[CI]，2.5至7.9）、营养不良（RR，4.0；95%CI，2.2至7.4）、新增三种以上药物（RR，2.9；95%CI，1.6至5.4）、使用膀胱导管（RR，2.4；95%CI，1.2至4.7）以及任何医源性事件（RR，1.9；95%CI，1.1至3.2）。每个诱发因素在谵妄发作前超过24小时出现。通过为每个存在的因素加1分建立了一个风险分层系统。低风险（0分）、中风险（1至2分）和高风险组（≥3分）的谵妄发生率分别为3%、20%和59%（P<.001）。验证队列中有47例患者（15%）发生谵妄，相应发生率分别为4%、20%和35%（P<.001）。当以交叉分层形式分析诱发因素和基线因素时，谵妄发生率在各个方向上从低风险组到高风险组逐渐增加（双梯度现象）。基线因素和诱发因素的作用被证明是独立且具有统计学意义的。
基于5个诱发因素的简单预测模型可用于识别老年内科患者中发生谵妄的高风险人群。诱发因素和基线脆弱性因素高度相关，并以独立、实质和累积的方式导致谵妄。
