Adelaide Health Technology Assessment (AHTA), Discipline of Public Health, School of Population Health, University of Adelaide, Adelaide, South Australia, Australia.
Int J Technol Assess Health Care. 2013 Jul;29(3):343-50. doi: 10.1017/S0266462313000287. Epub 2013 Jun 17.
A linked evidence approach (LEA) is the synthesis of systematically acquired evidence on the accuracy of a medical test, its impact on clinical decision making and the effectiveness of consequent treatment options. We aimed to assess the practical utility of this methodology and to develop a decision framework to guide its use.
As Australia has lengthy experience with LEA, we reviewed health technology assessment (HTA) reports informing reimbursement decisions by the Medical Services Advisory Committee (August 2005 to March 2012). Eligibility was determined according to predetermined criteria and data were extracted on test characteristics, evaluation methodologies, and reported difficulties. Fifty percent of the evidence-base was independently analyzed by a second reviewer.
Evaluations of medical tests for diagnostic (62 percent), staging (27 percent), and screening (6 percent) purposes were available for eighty-nine different clinical indications. Ninety-six percent of the evaluations used either the full LEA methodology or an abridged version (where evidence is linked through to management changes but not patient outcomes). Sixty-one percent had the full evidence linkage. Twenty-five percent of test evaluations were considered problematic; all involving LEA (n = 22). Problems included: determining test accuracy with an imperfect reference standard (41 percent); assessing likely treatment effectiveness in test positive patients when the new test is more accurate than the comparator (18 percent); and determining probable health benefits in those symptomatic patients ruled out using the test (13 percent). A decision framework was formulated to address these problems.
LEA is useful for evaluating medical tests but a stepped approach should be followed to determine what evidence is required for the synthesis.
关联证据方法（LEA）是对医学检验准确性、对临床决策的影响以及后续治疗方案有效性的系统获取证据的综合。我们旨在评估这种方法的实际效用，并制定一个决策框架来指导其使用。
由于澳大利亚在 LEA 方面拥有丰富的经验，我们对医疗服务咨询委员会（2005 年 8 月至 2012 年 3 月）做出报销决策所依据的卫生技术评估（HTA）报告进行了审查。根据预先确定的标准确定资格，并提取有关测试特征、评估方法和报告困难的数据。证据基础的 50%由第二位审阅者进行独立分析。
针对 89 种不同的临床指征，对用于诊断（62%）、分期（27%）和筛查（6%）目的的医学检验进行了评估。96%的评估使用了完整的 LEA 方法或简化版本（其中证据通过管理变更而不是患者结局进行链接）。61%的评估具有完整的证据链接。25%的测试评估被认为存在问题；全部涉及 LEA（n=22）。这些问题包括：用不完善的参考标准确定检验准确性（41%）；在新检验比比较检验更准确的情况下，评估检验阳性患者的可能治疗效果（18%）；以及在使用该检验排除症状患者时确定其可能的健康获益（13%）。制定了一个决策框架来解决这些问题。
LEA 对于评估医学检验很有用，但应采用逐步方法来确定综合所需的证据。
