Real-world clinical decision making is a complex process that involves balancing the risks and benefits of treatments. Quality-adjusted lifetime is a composite outcome that combines patient quantity and quality of life, making it an attractive outcome in clinical research. We propose methods for constructing optimal treatment length strategies to maximize this outcome. Existing methods for estimating optimal treatment strategies for survival outcomes cannot be applied to a quality-adjusted lifetime due to induced informative censoring. We propose a weighted estimating equation that adjusts for both confounding and informative censoring. We also propose a nonparametric estimator of the mean counterfactual quality-adjusted lifetime survival curve under a given treatment length strategy, where the weights are estimated using an undersmoothed sieve-based estimator. We show that the estimator is asymptotically linear and provide a data-dependent undersmoothing criterion. We apply our method to obtain the optimal time for percutaneous endoscopic gastrostomy insertion in patients with amyotrophic lateral sclerosis.

翻译：现实世界中的临床决策是一个复杂的过程，涉及平衡治疗的风险与获益。质量调整寿命是一种综合了患者生存数量与生活质量的复合结局指标，这使其在临床研究中成为一个具有吸引力的终点。我们提出了构建最优治疗时长策略以最大化该结局的方法。由于存在诱导的信息性删失，现有用于估计生存结局最优治疗策略的方法无法直接应用于质量调整寿命。我们提出了一种加权估计方程，可同时调整混杂因素和信息性删失的影响。我们还提出了一种非参数估计量，用于估计给定治疗时长策略下的平均反事实质量调整寿命生存曲线，其中权重通过使用欠平滑的基于筛法的估计量进行估计。我们证明了该估计量具有渐近线性性质，并提供了一个数据依赖的欠平滑准则。我们应用我们的方法来确定肌萎缩侧索硬化症患者经皮内镜下胃造口术插入的最佳时机。