Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA.
Department of Mathematics, West Chester University, West Chester, PA, USA.
Psychother Res. 2023 Feb;33(2):158-172. doi: 10.1080/10503307.2022.2073289. Epub 2022 May 11.
Psychotherapy randomized trials rarely have tested for the best fitting model for time effects. We examined the fit of different statistical models for examining time when repeated assessments of depressive symptoms are the primary outcome.
We used data from three studies comparing psychotherapy treatments for major depressive disorder. Outcome measures were self-report ratings for Study 1 (= 237) and Study 2 (= 100) and clinician ratings for Study 3 (= 120) of depressive symptoms measured at every session (Studies 1 and 2) or monthly (Study 3). We examined the fit of the following time patterns: linear, quadratic, cubic, log transformation of time, piece-wise linear, and unstructured.
In Study 1, a log-linear model had the best fit (Δ Akaike information criterion [AICc] = 7.5). In Study 2, all models had essentially no support (Δ AICcs > 10) in comparison to the best fitting model, which was the unstructured model. In Study 3, the cubic model had the best fit, but it was not significantly better than a log-linear (Δ AICc = 3.5) or unstructured model (Δ AICc = 2.5).
Trials should routinely compare different time models, including an unstructured model, when repeated measures of depressive symptoms are the primary outcome.
心理治疗随机试验很少测试时间效应的最佳拟合模型。我们检验了不同统计模型在重复评估抑郁症状为主要结局时拟合时间的效果。
我们使用了三项比较主要抑郁障碍心理治疗的研究的数据。研究 1（=237）和研究 2（=100）的结局测量为自我报告的抑郁症状评分，研究 3（=120）的结局测量为临床医生对抑郁症状的每月评估。我们检验了以下时间模式的拟合效果：线性、二次、三次、时间的对数转换、分段线性和非结构化。
在研究 1 中，对数线性模型具有最佳拟合（Δ Akaike 信息准则[AICc] = 7.5）。在研究 2 中，与最佳拟合模型（非结构化模型）相比，所有模型的支持度都基本没有（Δ AICcs > 10）。在研究 3 中，三次模型具有最佳拟合，但与对数线性模型（Δ AICc = 3.5）或非结构化模型（Δ AICc = 2.5）相比，差异无统计学意义。
当重复评估抑郁症状为主要结局时，试验应常规比较不同的时间模型，包括非结构化模型。
