Behavioral Influence of Known Prognostic Markers on the Cardiologist's Decision following Acute Coronary Syndrome: the GRACE Score Paradox

Abstract Background: Behavioral scientists consistently point out that knowledge does not influence decisions as expected. GRACE Score is a well validated risk model for predicting death of patients with acute coronary syndromes (ACS). However, whether prognostic assessment by this Score modulates medical decision is not known. Objective: To test the hypothesis that the use of a validated risk score rationalizes the choice of invasive strategies for higher risk patients with non-ST-elevation ACS. Methods: ACS patients were consecutively included in this prospective registry. GRACE Score was routinely used by cardiologists as the prognostic risk model. An invasive strategy was defined as an immediate decision of the coronary angiography, which in the selective strategy was only indicated in case of positive non-invasive test or unstable course. Firstly, we evaluated the association between GRACE and invasiviness; secondly, in order to find out the actual determinants of the invasive strategy, we built a propensity model for invasive decision. For this analysis, a p-value < 0.05 was considered as significant. Results: In a sample of 570 patients, an invasive strategy was adopted for 394 (69%). GRACE Score was 118 ± 38 for the invasive group, similar to 116 ± 38 for the selective group (p = 0.64). A propensity score for the invasive strategy was derived from logistic regression: positive troponin and ST-deviation (positive associations) and hemoglobin (negative association). This score predicted an invasive strategy with c-statistics of 0.68 (95%CI: 0.63-0.73), opposed to GRACE Score (AUC 0.51; 95%CI: 0.47-0.57). Conclusion: The dissociation between GRACE Score and invasive decision in ACS suggests that the knowledge of prognostic probabilities might not determine medical decision.

摘要 背景：行为科学家始终指出，知识并不会如预期般影响临床决策。GRACE评分（GRACE Score）是一款经过充分验证的风险模型，用于预测急性冠状动脉综合征（acute coronary syndromes, ACS）患者的死亡风险。然而，采用该评分开展预后评估是否会调节临床医疗决策，目前尚不明确。
研究目的：验证下述假说，即使用经过验证的风险评分，可使非ST段抬高型ACS高危患者的有创治疗策略选择更趋合理化。
研究方法：本前瞻性登记研究连续纳入ACS患者，心血管医师常规采用GRACE评分作为预后风险评估模型。有创治疗策略定义为即刻实施冠状动脉造影的决策，而选择性治疗策略则仅在无创检查结果阳性或病情出现不稳定进展时才予以采用。首先，我们评估了GRACE评分与有创治疗实施程度之间的关联；其次，为明确有创治疗策略选择的实际决定因素，我们构建了用于预测有创治疗决策的倾向性评分模型。本分析以p值<0.05作为显著性检验阈值。
研究结果：在570例患者的研究样本中，394例（69%）采用了有创治疗策略。有创治疗组的GRACE评分为118±38，与选择性治疗组的116±38相近（p=0.64）。通过logistic回归分析推导得到有创治疗决策的倾向性评分：肌钙蛋白阳性、ST段偏移与有创治疗呈正相关，而血红蛋白水平呈负相关。该评分预测有创治疗策略的C统计量为0.68（95%CI：0.63~0.73），而GRACE评分的曲线下面积（AUC）为0.51（95%CI：0.47~0.57）。
研究结论：ACS患者中GRACE评分与有创治疗决策之间的分离现象提示，预后概率相关知识可能并未决定临床医疗决策。