Man-Son-Hing M, Laupacis A, O'Connor A M, Coyle D, Berquist R, McAlister F
Geriatric Assessment Unit, Ottawa Hospital, University of Ottawa, Ontario, Canada.
Med Decis Making. 2000 Oct-Dec;20(4):394-403. doi: 10.1177/0272989X0002000403.
Decision analysis (DA) and the probability-tradeoff technique (PTOT) are patient preference-based methods of determining optimal therapy for individuals. Using aspirin therapy for the primary prevention of stroke and myocardial infarction (MI) in elderly persons as an example, the objective of this study was to determine whether group-level treatment thresholds and individual-level treatment recommendations derived using PTOT are identical to those of DA incorporating the patients' own values.
Persons in a pilot study of the efficacy of aspirin in the prevention of stroke and MI were asked to participate. Participant values and utilities for pertinent health states (e.g., minor and major stroke, MI, major bleeding episode) were determined. Then, in three hypothetical clinical situations in which the chance of stroke or MI was varied, PTOT was used to directly determine treatment thresholds for aspirin therapy (i.e., the smallest reduction in MI or stroke risk for which participants would be willing to take aspirin). Using DA modeling, with the same probabilities of events as in the PTOT exercise and incorporating participants' own values, treatment thresholds for the three clinical situations were determined. The thresholds determined by the two approaches were compared. Finally, based on these treatment thresholds, using the best estimates of the efficacy of aspirin to prevent first-time stroke and MI, PTOT and DA treatment recommendations for individual participants were compared.
The 42 participants reported that a major stroke was the least desirable health state, followed by MI, minor stroke, and major bleeding. The minimum risk reduction required to take aspirin was greater for MI prevention compared with stroke prevention. For the two clinical situations in which the hypothetical efficacy of aspirin to prevent stroke was varied, treatment thresholds for the PTOT versus DA approaches differed (p < 0.04), but this difference was not significant (p = 0.19) for the MI-based clinical situation. Using the best estimate of the efficacy of aspirin to prevent first-time stroke and MI, PTOT and DA treatment recommendations whether or not to take aspirin were discordant for 38% of participants (16 of 42) (p < 0.001).
Patient preference-based group-level treatment thresholds and individual-level treatment recommendations can differ significantly depending on whether PTOT or DA is used, apparently because the two emphasize different aspects of the decision-making process. DA theory assumes that effective therapeutic decision making should maximize both quality and quantity of life; with PTOT, the emphasis for effective clinical decision making allows patients to be fully engaged in the process, thus hopefully leading to fully informed decisions that may result in satisfaction and compliance.
决策分析（DA）和概率权衡技术（PTOT）是基于患者偏好来确定个体最佳治疗方案的方法。以阿司匹林用于老年人中风和心肌梗死（MI）一级预防为例，本研究的目的是确定使用PTOT得出的群体水平治疗阈值和个体水平治疗建议是否与纳入患者自身价值观的DA相同。
邀请参与阿司匹林预防中风和MI疗效初步研究的人员参与。确定参与者对相关健康状态（如轻度和重度中风、MI、大出血事件）的价值观和效用。然后，在三种中风或MI发生几率不同的假设临床情况下，使用PTOT直接确定阿司匹林治疗的阈值（即参与者愿意服用阿司匹林的MI或中风风险最小降低值）。使用DA模型，采用与PTOT练习相同的事件概率并纳入参与者自身价值观，确定三种临床情况的治疗阈值。比较两种方法确定的阈值。最后，基于这些治疗阈值，利用阿司匹林预防首次中风和MI疗效的最佳估计值，比较PTOT和DA对个体参与者的治疗建议。
42名参与者表示，重度中风是最不理想的健康状态，其次是MI、轻度中风和大出血。与预防中风相比，预防MI服用阿司匹林所需的最小风险降低值更大。在阿司匹林预防中风假设疗效不同的两种临床情况下，PTOT与DA方法的治疗阈值存在差异（p<0.04），但在基于MI的临床情况下，这种差异不显著（p = 0.19）。利用阿司匹林预防首次中风和MI疗效的最佳估计值，PTOT和DA关于是否服用阿司匹林的治疗建议在38%的参与者（42名中的16名）中不一致（p<0.001）。
基于患者偏好的群体水平治疗阈值和个体水平治疗建议可能因使用PTOT还是DA而有显著差异，显然是因为两者强调决策过程的不同方面。DA理论假设有效的治疗决策应使生活质量和数量最大化；而对于PTOT，有效临床决策的重点是让患者充分参与该过程，从而有望做出充分知情的决策，可能带来满意度和依从性。
