Biostatistics Unit, University of Genoa, Genova, Italy.
J Neurol Sci. 2009 Dec;287 Suppl 1:S46-9. doi: 10.1016/S0022-510X(09)71300-0.
The 'Will Rogers phenomenon' is an apparent epidemiological paradox named after a remark made by the humorist Will Rogers about migration during the American economic depression of the 1930's: "When the Okies left Oklahoma and moved to California, they raised the average intelligence level in both states." In 1985, Alvan Feinstein proposed the name 'Will Rogers Phenomenon' to describe the 'stage migration' he observed in patients with cancer. Changes in the criteria for assigning patients to the various stages of a disease can produce spurious improvements in stage-specific prognosis, even though the outcome of individual patients has not changed. In oncology, new imaging tools allowed detection of cancer metastases before they became evident clinically. In consequence, more patients are classified into the more severe metastatic disease stage from the less severe single tumour stage. Such a 'stage migration' resulted in an improved survival of patients in both the less and the more severe disease stages. Multiple sclerosis is also subject to the Will Rogers phenomenon since the introduction of the imaging-assisted McDonald criteria. Given the sensitivity of magnetic resonance imaging for detecting disease activity, which is believed to be five to ten times greater than that of clinical assessment, the McDonald criteria are expected to allow earlier diagnosis, hence the 'stage migration' relative to the previous Poser diagnostic criteria. Because of the ethical problems associated with carrying out placebo-controlled trials in multiple sclerosis owing to the wider availability of therapeutic options, the use of historical controls groups remains an attractive option. However, the Will Rogers phenomenon, which is recognised as one of the most important biases limiting the use of historical controls groups in experimental treatment trials, compromises the interest of this approach. In this context, the use of different diagnostic criteria may generate spurious improvements in the medium-term prognosis of multiple sclerosis, which may be wrongly interpreted as treatment effects.
“Will Rogers 现象”是一个明显的流行病学悖论，以幽默家 Will Rogers 在 20 世纪 30 年代美国经济大萧条时期关于移民的言论命名：“当俄克拉荷马州的 Okies 离开俄克拉荷马州并搬到加利福尼亚州时，他们提高了这两个州的平均智力水平。”1985 年，Alvan Feinstein 提出了“Will Rogers 现象”这个名称来描述他在癌症患者中观察到的“分期迁移”。改变疾病各分期的分配标准可能会导致分期特异性预后的虚假改善，尽管个别患者的结果没有改变。在肿瘤学中，新的成像工具允许在癌症转移变得明显之前检测到它们。因此，更多的患者被分类为更严重的转移性疾病阶段，而不是更轻微的单一肿瘤阶段。这种“分期迁移”导致患者在较轻和较重疾病阶段的生存率都有所提高。多发性硬化症也受到 Will Rogers 现象的影响，因为引入了成像辅助的 McDonald 标准。鉴于磁共振成像（MRI）对检测疾病活动的敏感性被认为比临床评估高五到十倍，因此 McDonald 标准有望更早地诊断疾病，从而与以前的 Poser 诊断标准相比出现“分期迁移”。由于在多发性硬化症中由于治疗选择的广泛可用性而存在与安慰剂对照试验相关的伦理问题，因此使用历史对照组仍然是一个有吸引力的选择。然而，Will Rogers 现象被认为是限制历史对照组在实验治疗试验中应用的最重要偏见之一，这损害了这种方法的利益。在这种情况下，使用不同的诊断标准可能会导致多发性硬化症的中期预后出现虚假改善，这可能被错误地解释为治疗效果。
