Gerke Oke, Poulsen Mads H, Høilund-Carlsen Poul Flemming
Department of Nuclear Medicine, Odense University Hospital Denmark ; Centre of Health Economics Research, Department of Business and Economics, Faculty of Business and Social Sciences, University of Southern Denmark Denmark.
Department of Urology, Odense University Hospital Denmark.
Am J Nucl Med Mol Imaging. 2015 Jan 15;5(2):183-94. eCollection 2015.
Diagnostic studies of accuracy targeting sensitivity and specificity are commonly done in a paired design in which all modalities are applied in each patient, whereas cost-effectiveness and cost-utility analyses are usually assessed either directly alongside to or indirectly by means of stochastic modeling based on larger randomized controlled trials (RCTs). However the conduct of RCTs is hampered in an environment such as ours, in which technology is rapidly evolving. As such, there is a relatively limited number of RCTs. Therefore, we investigated as to which extent paired diagnostic studies of accuracy can be also used to shed light on economic implications when considering a new diagnostic test. We propose a simple decision tree model-based cost-utility analysis of a diagnostic test when compared to the current standard procedure and exemplify this approach with published data from lymph node staging of prostate cancer. Average procedure costs were taken from the Danish Diagnosis Related Groups Tariff in 2013 and life expectancy was estimated for an ideal 60 year old patient based on prostate cancer stage and prostatectomy or radiation and chemotherapy. Quality-adjusted life-years (QALYs) were deduced from the literature, and an incremental cost-effectiveness ratio (ICER) was used to compare lymph node dissection with respective histopathological examination (reference standard) and (18)F-fluoromethylcholine positron emission tomography/computed tomography (FCH-PET/CT). Lower bounds of sensitivity and specificity of FCH-PET/CT were established at which the replacement of the reference standard by FCH-PET/CT comes with a trade-off between worse effectiveness and lower costs. Compared to the reference standard in a diagnostic accuracy study, any imperfections in accuracy of a diagnostic test imply that replacing the reference standard generates a loss in effectiveness and utility. We conclude that diagnostic studies of accuracy can be put to a more extensive use, over and above a mere indication of sensitivity and specificity of an imaging test, and that health economic considerations should be undertaken when planning a prospective diagnostic accuracy study. These endeavors will prove especially fruitful when comparing several imaging techniques with one another, or the same imaging technique using different tracers, with an independent reference standard for the evaluation of results.
针对敏感性和特异性的准确性诊断研究通常采用配对设计，即对每位患者应用所有检查方法，而成本效益分析和成本效用分析通常要么直接与大型随机对照试验（RCT）同时进行评估，要么通过基于这些试验的随机建模间接评估。然而，在我们这样一个技术快速发展的环境中，RCT的开展受到了阻碍。因此，随机对照试验的数量相对有限。所以，我们研究了在考虑一种新的诊断测试时，配对准确性诊断研究在多大程度上也可用于阐明其经济影响。我们提出了一种基于简单决策树模型的诊断测试成本效用分析方法，与当前标准程序进行比较，并以前列腺癌淋巴结分期的已发表数据为例进行说明。平均程序成本取自2013年丹麦诊断相关组收费标准，并根据前列腺癌分期以及前列腺切除术、放疗和化疗情况，对一名理想的60岁患者的预期寿命进行了估算。质量调整生命年（QALY）从文献中推导得出，并使用增量成本效益比（ICER）来比较淋巴结清扫术与各自的组织病理学检查（参考标准）以及（18）F - 氟甲基胆碱正电子发射断层扫描/计算机断层扫描（FCH - PET/CT）。确定了FCH - PET/CT敏感性和特异性的下限，在该下限下，用FCH - PET/CT替代参考标准会在效果变差和成本降低之间进行权衡。与诊断准确性研究中的参考标准相比，诊断测试准确性方面的任何缺陷都意味着替代参考标准会导致效果和效用的损失。我们得出结论，准确性诊断研究可以有更广泛的用途，不仅仅是用于表明成像测试的敏感性和特异性，并且在规划前瞻性诊断准确性研究时应考虑健康经济学因素。当将几种成像技术相互比较，或者使用不同示踪剂的同一种成像技术与用于评估结果的独立参考标准进行比较时，这些努力将尤其富有成效。
