当确定性杀死：CAST 故事

Not every bright sign is guidance.

这不是一个关于错误的故事。

这是一个关于确定性的故事。

幻灯片 3：钩子

50,000

deaths per year

From a treatment everyone believed worked.

这是一个关于我们如何相信以及我们如何成为的故事错误。

幻灯片 4：观察

The Observation

Patients with frequent PVCs after MI had 2–5× higher mortality.

400,000+

MI survivors/year

~40%

具有显着的 PVC

160,000

at elevated risk

A massive clinical need. A clear target.

幻灯片 5：响应

The Response

Antiarrhythmic drugs were developed, FDA approved,
and prescribed to ~200,000 patients per year.

这个故事中没有出现恶棍。

每个人都根据最佳证据采取行动可用。

说服所有人的逻辑

PREMISE 1

PVCs after MI predict sudden cardiac death

↓

PREMISE 2

Antiarrhythmic drugs suppress PVCs

↓

PREMISE 3

Suppressing PVCs should prevent sudden death

↓

CONCLUSION

Antiarrhythmics save lives in post-MI patients

链条是合乎逻辑的。结论感觉是不可避免的。

CAST: The Cardiac Arrhythmia Suppression Trial

Finally, someone asked: "Does suppressing PVCs actually save lives?"

Design

Randomized, double-blind, placebo-controlled

Population

Post-MI patients with asymptomatic PVCs

Intervention

Encainide, flecainide, or moricizine vs placebo

Run-in

Only patients with ≥80% PVC suppression randomized

Primary endpoint

Death or cardiac arrest with resuscitation

Sample size

1,498 patients (encainide/flecainide arms)

Outcome tested: survival. Not assumed. Measured.

幻灯片 8：结果表

结果：1989 年 4 月

数据安全监测委员会提前停止了试验。

Outcome	Drug (n=755)	Placebo (n=743)
Arrhythmic deaths	33	9
All cardiac deaths	43	16
Total deaths	56	22
Death rate	7.4%	3.0%

Relative Risk of Death: 2.5

95% CI: 1.6 – 4.5 | p < 0.001

完美抑制心律失常的药物增加了死亡率150%。

Forest Plot: CAST Mortality Results

Outcome

Drug

Placebo

RR (95% CI)

Arrhythmic death

33/755

9/743

3.6 (1.7-7.5)

Cardiac death

43/755

16/743

2.6 (1.5-4.7)

Total mortality

56/755

22/743

2.5 (1.5-4.0)

Overall

56/755

22/743

2.5 (1.5-4.0)

Favors Drug Favors Placebo

Every endpoint shows harm. The entire confidence interval excludes benefit.

Note: Forest plot shows outcomes within CAST, not pooled trials. I² = 0% (consistent harm).

人力成本

Before CAST, ~200,000 Americans per year received these drugs.

≈ 9,000

excess deaths per year — possibly more

Vietnam War: ~6,000 US deaths/year • These drugs: ~9,000+ deaths/year

For every number, a name we will never know.

Look again.

幻灯片 12：重新审视逻辑（带有飞跃）

重新审视逻辑

PREMISE 1

PVCs after MI predict sudden cardiac death

↓

PREMISE 2

Antiarrhythmic drugs suppress PVCs

← THE LEAP

↓

PREMISE 3

Suppressing PVCs should prevent sudden death

↓

CONCLUSION

Antiarrhythmics save lives in post-MI patients

抑制标记会修复结果的假设从来都不是

What Went Wrong: The Surrogate Trap

PVC 是受损组织的标志，而不是死亡原因

The drugs had proarrhythmic effects — triggering deadlier rhythms

替代者有所改善，但结果恶化 - 分离的替代者

替代者没有撒谎。我们问了错误的问题。

幻灯片 14：教训

证据合成的教训

生物学合理性不是证据

A logical mechanism doesn't guarantee the expected effect.

Surrogate endpoints can mislead

Improving a biomarker doesn't prove improvement in outcomes.

Only randomized trials establish causation

Observational data cannot prove intervention effects.

共识不是证据证据

200,000张处方、FDA批准和指南都是错误的。

This is why we do meta-analysis: to see past apparent truths.

What appears certain may be wrong.

What everyone believes may be false.

方法的存在是为了让患者不必为我们的信心付出代价。

这就是您来到这里的原因。

Not every bright sign is guidance.

方法保护患者不受我们信心的影响。