Howard Kirsten, Salkeld Glenn, Irwig Les, Adelstein Barbara-Ann
Health Economics, Screening and Test Evaluation Program (STEP), School of Public Health, Edward Ford Building A27, University of Sydney, Australia.
J Med Screen. 2005;12(2):96-102. doi: 10.1258/0969141053908276.
In many countries high participation is an explicit target in screening programmes. The desire for high participation often appears to drive screening policy, although it is increasingly recognized that encouraging high participation may impinge upon the rights of an individual to make an informed choice. One argument offered in support of high participation is that it improves the cost-effectiveness of screening. This is questionable on theoretical grounds, and empirically there are conflicting results. Two recent cost-effectiveness models of faecal occult blood test (FOBT) screening for colorectal cancer (CRC) showed that cost-effectiveness was improved, another showed that cost-effectiveness was worsened and a fourth indicated that cost-effectiveness was unaffected by increasing the participation rate.
We assessed the extent to which different levels and patterns of participation affect cost-effectiveness, using decision modelling of three CRC screening with FOBT scenarios. We estimate the incremental cost-effectiveness (value for money) ratios for each scenario.
The way in which participation is modelled, particularly assumptions made about the subsequent screening behaviour of non-participants ("if" and "when" a non-participant attends for subsequent screening), affects the cost-effectiveness estimates for FOBT screening programmes. 100% participation in all screening rounds gives a cost per life year saved (LYS) of USD 9705. Cost-effectiveness is worst when people who do not take part in one screening round (initial or subsequent) never take part in any future rounds of screening. Under this scenario, a participation rate of 20% in second and subsequent rounds gives a cost per LYS of USD 29,500. Under more realistic assumptions, for example the attendance of even a small proportion of non-participants in subsequent rounds, cost-effectiveness is more favourable and similar to that achieved for full participation: the scenario with a random participation rate of 20% in second and subsequent rounds for both participants and non-participants has a cost per LYS of USD 11,270.
Contrary to a commonly held view, high participation in screening programmes is not necessary to achieve cost-effectiveness. Setting high target participation rates in screening programmes does not guarantee cost-effectiveness and may in certain circumstances reduce the cost-effectiveness.
在许多国家，高参与率是筛查项目的一个明确目标。对高参与率的追求似乎常常推动着筛查政策，尽管人们越来越认识到鼓励高参与率可能会侵犯个人做出明智选择的权利。支持高参与率的一个论点是，它能提高筛查的成本效益。这在理论上是有疑问的，而且实证结果也相互矛盾。最近两个针对结直肠癌（CRC）的粪便潜血试验（FOBT）筛查成本效益模型显示成本效益得到了改善，另一个模型显示成本效益恶化，还有第四个模型表明成本效益不受参与率提高的影响。
我们通过对三种FOBT CRC筛查方案进行决策建模，评估不同参与水平和模式对成本效益的影响程度。我们估计每种方案的增量成本效益（性价比）比率。
参与情况的建模方式，特别是关于未参与者后续筛查行为的假设（“如果”以及“何时”未参与者参加后续筛查），会影响FOBT筛查项目的成本效益估计。所有筛查轮次的参与率达到100%时，每挽救一个生命年（LYS）的成本为9705美元。当未参加某一轮筛查（初始轮或后续轮）的人从不参加未来任何一轮筛查时，成本效益最差。在这种情况下，第二轮及后续轮次20%的参与率会使每LYS成本达到29500美元。在更现实的假设下，例如即使有一小部分未参与者参加后续轮次，成本效益会更有利且与完全参与时相似：第二轮及后续轮次参与者和未参与者的随机参与率均为20%的方案，每LYS成本为11270美元。
与普遍观点相反，筛查项目要实现成本效益并非必须要有高参与率。在筛查项目中设定高目标参与率并不能保证成本效益，而且在某些情况下可能会降低成本效益。
