Faculty of Medicine, School of Physical and Occupational Therapy, McGill University, 3654 Prom Sir-William-Osler, Montreal, QC H3G 1Y5, Canada.
Qual Life Res. 2011 Dec;20(10):1555-60. doi: 10.1007/s11136-011-0005-6. Epub 2011 Oct 21.
Individuals experiencing a change in health may experience a response shift that may attenuate HRQoL change estimates. The objective of this study was to estimate the proportion of individuals with multiple sclerosis (MS) who experienced a response shift as detected by the Latent Trajectory of Residuals approach.
Participants in the NARCOMS Registry were included if they responded to the general health (GH) question of the SF-12 in at least 3 surveys. Linear growth modeling was used to identify predictors of self-reported GH, and the residuals from this model were used to determine group-based trajectories. Dual trajectories of GH and a measure of disability (PDSS) were used to examine convergence in change patterns over time.
A total of 1,566 individuals were included in this study. The predictive GH model explained 55% of the variance; 99.7% of subjects did not experience a response shift as indicated by flat trajectories, and 0.3% lowered their rating of health as compared to predicted indicating a potential response shift. Among 13% of subjects with flat trajectories of PDDS, 5% had GH decreasing most strongly showing some discordance between symptoms and GH.
A lower percentage of individuals experienced response shift than previous research on smaller samples. These results may indicate the true absence of response shift, or may be limited by using a categorical outcome of GH, and GH predictors that may have also been amenable to response shift, which decreases the appropriateness of using the LTA approach. Future work will include the use of growth curve latent class analyses to assess response shift.
健康状况发生变化的个体可能会经历反应转移，从而可能减弱对 HRQoL 变化的估计。本研究的目的是估计经历反应转移的多发性硬化症（MS）个体的比例，该转移通过潜伏轨迹残余法（Latent Trajectory of Residuals approach）检测。
如果参与者在至少 3 次调查中回答了 SF-12 的一般健康（GH）问题，则将其纳入 NARCOMS 注册表。线性增长模型用于确定自我报告的 GH 的预测因素，并且该模型的残差用于确定基于群组的轨迹。使用 GH 和残疾测量（PDSS）的双重轨迹来检验随着时间的推移变化模式的收敛性。
共有 1566 人参加了这项研究。预测 GH 模型解释了 55%的方差；99.7%的受试者没有表现出反应转移，这表明轨迹平坦，而 0.3%的受试者的健康评分比预测值低，表明可能存在反应转移。在 PDDS 轨迹平坦的 13%的受试者中，有 5%的 GH 下降最强，表明症状和 GH 之间存在一些不和谐。
与以前对较小样本的研究相比，经历反应转移的个体比例较低。这些结果可能表明确实不存在反应转移，或者可能受到使用 GH 的分类结果和可能也容易受到反应转移影响的 GH 预测因素的限制，这降低了使用 LTA 方法的适当性。未来的工作将包括使用增长曲线潜在类别分析来评估反应转移。
