Division of Nephrology, Tufts Medical Center, Boston, MA 02111, USA.
J Gen Intern Med. 2010 Oct;25(10):1083-9. doi: 10.1007/s11606-010-1445-3. Epub 2010 Jul 20.
Decisions to limit treatment in critically ill patients often rely on publications that make claims of futility based on outcome data. Our objective was to systematically review the criteria for futility and the strength of empirical evidence across clinical studies that purport to support or refute claims of futility.
The MEDLINE database was searched for relevant articles published between 1980 and 2008. Selected studies reported original outcome data in critically ill or cardiac arrest patients and claimed that these data can support or refute decisions to limit treatment in comparable patients. Two authors independently abstracted data on patient characteristics, intervention, outcomes, cost, and design.
Forty seven studies supporting a claim of futility and 45 refuting it were reviewed. Median point estimate for adverse outcome in studies supporting claims of futility was 100% (range 75% to 100%); median lower 95% confidence limit was 91% (range 48% to 99%). Explicit thresholds for futility were missing in 88% of articles. The original criteria for quantitative futility were fulfilled by only 28% of data, and almost exclusively in studies of cardiopulmonary resuscitation (CPR) for cardiac arrest. Substantial statistical overlap was observed between data brought in support of futility claims and data brought to refute them.
Most studies that purport to guide determinations of futility are based on insufficient data to provide statistical confidence for clinical decision-making. They usually lack explicit a priori thresholds for determination of futility. Many studies draw disparate conclusions based on statistically similar data. In most circumstances these problems preclude confident determinations of futility.
在危重病患者中进行治疗限制的决策通常依赖于那些根据结果数据提出无效性主张的出版物。我们的目的是系统地回顾声称支持或反驳无效性主张的临床研究中的无效性标准和经验证据的强度。
在 1980 年至 2008 年期间，我们在 MEDLINE 数据库中搜索了相关的文章。选定的研究报告了在危重病或心脏骤停患者中进行的原始结果数据，并声称这些数据可以支持或反驳在可比患者中进行治疗限制的决策。两位作者独立地摘录了患者特征、干预、结果、成本和设计的数据。
我们回顾了 47 项支持无效性主张的研究和 45 项反驳无效性主张的研究。支持无效性主张的研究中不良结果的中位数点估计为 100%（范围 75%至 100%）；中位数 95%置信下限为 91%（范围 48%至 99%）。88%的文章中缺失了无效性的明确阈值。只有 28%的数据符合定量无效性的原始标准，而且几乎仅在心脏骤停的心肺复苏（CPR）研究中符合。支持无效性主张的数据和反驳无效性主张的数据之间观察到了大量的统计学重叠。
大多数声称指导无效性判断的研究都是基于不足的数据，无法为临床决策提供统计学上的信心。它们通常缺乏明确的事先无效性阈值。许多研究基于统计学上相似的数据得出了不同的结论。在大多数情况下，这些问题使得无法确定无效性。
