Department of Social Medicine and Prevention, Institute of Community Medicine, University Medicine Greifswald, Walther-Rathenau-Str. 48, 17475, Greifswald, Germany.
DZHK (German Center for Cardiovascular Research), Partner Site Greifswald, Greifswald, Germany.
BMC Psychiatry. 2021 Aug 4;21(1):386. doi: 10.1186/s12888-021-03390-0.
The Patient Health Questionnaire-8 (PHQ-8) is a screening questionnaire of depressive symptoms. However, it is unknown whether it is equivalent across time and between groups of individuals. The aim of our paper was to test whether the PHQ-8 has the same meaning in two groups of individuals over time.
Primary care patients were proactively recruited from three German cities. PHQ-8 data from a baseline assessment (n = 588), two assessments during the intervention (n = 246/225), and a six (n = 437) and 12 months (n = 447) follow-up assessment were first used to examine the factor structure of the PHQ-8 by confirmatory factor analysis (CFA). The best fitting factor solution was then used to test longitudinal invariance across time and between intervention and control group by Multiple Group CFA.
A two-factor structure consistently showed the best model fit. Only configural longitudinal invariance was evidenced when the baseline assessment was included in the analysis. Without the baseline assessment, strict longitudinal invariance was shown across the intervention and the follow-up assessments. Scalar invariance was established between the intervention and control group for the baseline assessment and strict invariance between groups and across the 6- and 12-month follow-up assessments.
The lack of longitudinal invariance might be attributed to various differences between the baseline assessments and all following assessments, e.g., assessment mode (iPad vs telephone), potential changes in symptom perception, and setting.
DRKS0001163 5, date of trial registration: 20.01.2017; DRKS00011637 , date of trial registration: 25.01.2017.
患者健康问卷-8（PHQ-8）是一种用于筛查抑郁症状的问卷。然而，其在不同时间和不同个体群体之间是否具有等效性尚不清楚。本文旨在检验 PHQ-8 在两个时间点和两个个体群体中是否具有相同的含义。
从德国的三个城市主动招募初级保健患者。首先使用 PHQ-8 的基线评估数据（n=588）、干预期间的两次评估数据（n=246/225）以及 6 个月（n=437）和 12 个月（n=447）的随访评估数据，通过验证性因子分析（CFA）检验 PHQ-8 的因子结构。然后，使用最佳拟合因子解通过多组 CFA 检验跨时间和干预组与对照组的纵向不变性。
始终呈现出两因素结构的最佳模型拟合。仅在包含基线评估的情况下才能证明配置纵向不变性。不包括基线评估，干预和随访评估之间显示出严格的纵向不变性。在基线评估中，干预组和对照组之间建立了标量不变性，在干预组和 6 个月和 12 个月的随访评估中建立了严格的组间不变性。
纵向不变性的缺乏可能归因于基线评估和所有后续评估之间的各种差异，例如评估模式（iPad 与电话）、症状感知的潜在变化以及环境。
DRKS0001163，试验注册日期：2017 年 1 月 20 日；DRKS00011637，试验注册日期：2017 年 1 月 25 日。
