Life expectancy difference and life expectancy ratio: two measures of treatment effects in randomised trials with non-proportional hazards.
Life expectancy difference and life expectancy ratio: two measures of treatment effects in randomised trials with non-proportional hazards.
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DOI：
10.1136/bmj.j2250
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发表时间：
2017-05-25
期刊：
影响因子：
--
通讯作者：
Hackshaw A
中科院分区：
文献类型：
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作者：
Dehbi HM;Royston P;Hackshaw A
风险比（HR）是临床试验中最常见的治疗效果指标，使用时间至事件结局（如生存期）。当生存曲线仅在相当长的时间后交叉或分离时，违反了考克斯模型的比例风险假设，HR可能会产生误导。我们提出了两个措施的治疗效果的情况下，随着时间的推移，HR变化：预期寿命差异（LED）和预期寿命比（LER）。LED是干预组和对照组的平均生存时间之差。LER是这两个时间的比值。LED和LER可以在试验期间至少计算两个时间间隔，允许治疗效果随时间变化的曲线。这两项措施很容易解释为预期寿命的绝对和相对收益或损失。
The hazard ratio (HR) is the most common measure of treatment effect in clinical trials that use time-to-event outcomes such as survival. When survival curves cross over or separate only after a considerable time, the proportional hazards assumption of the Cox model is violated, and HR can be misleading. We present two measures of treatment effects for situations where the HR changes over time: the life expectancy difference (LED) and life expectancy ratio (LER). LED is the difference between mean survival times in the intervention and control arms. LER is the ratio of these two times. LED and LER can be calculated for at least two time intervals during the trial, allowing for curves where the treatment effect changes over time. The two measures are readily interpretable as absolute and relative gains or losses in life expectancy.