OBJECTIVE The mechanisms of change in digital interventions for the prevention of depression are largely unknown. Here, we explored whether five theoretically derived intervening variables (i.e., pain intensity, pain-related disability, pain self-efficacy, quality of life [QoL], and work capacity) were mediating the effectiveness of a digital intervention specifically designed to prevent depression in patients with chronic back pain (CBP). METHOD This study is a secondary analysis of a pragmatic, observer-masked randomized clinical trial conducted at 82 orthopedic clinics in Germany. A total of 295 adults with a diagnosis of CBP and subclinical depressive symptoms were randomized to either the intervention group (n = 149) or treatment-as-usual (n = 146). Longitudinal mediation analyses were conducted with structural equation modeling and depression symptom severity as primary outcome (Patient Health Questionnaire-9 [PHQ-9]; 6 months after randomization) on an intention-to-treat basis. RESULTS Beside the effectiveness of the digital intervention in preventing depression, we found a significant causal mediation effect for QoL as measured with the complete scale of Assessment of Quality of Life (AQoL-6D; axb: -0.234), as well as for the QoL subscales mental health (axb: -0.282) and coping (axb: -0.249). All other potential intervening variables were not significant. CONCLUSION Our findings suggest a relevant role of QoL, including active coping, as change mechanism in the prevention of depression. Yet, more research is needed to extend and specify our knowledge on empirically supported processes in digital depression prevention. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

中文翻译：

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慢性背痛患者预防数字抑郁的中介因素：多中心随机临床试验的结果。

目的 预防抑郁症的数字干预措施的变化机制在很大程度上尚不清楚。在这里，我们探讨了五个理论上推导的干预变量（即疼痛强度、疼痛相关残疾、疼痛自我效能、生活质量 [QoL] 和工作能力）是否在调节专门为预防抑郁症而设计的数字干预措施的有效性慢性背痛（CBP）患者。方法 本研究是对在德国 82 家骨科诊所进行的务实、观察者屏蔽的随机临床试验的二次分析。总共 295 名被诊断为 CBP 和亚临床抑郁症状的成年人被随机分配到干预组 (n = 149) 或照常治疗组 (n = 146)。在意向治疗的基础上，以结构方程模型和抑郁症状严重程度作为主要结局（患者健康问卷-9 [PHQ-9]；随机化后 6 个月）进行纵向中介分析。结果 除了数字干预在预防抑郁方面的有效性之外，我们还发现，通过生活质量评估完整量表（AQoL-6D；axb：-0.234）以及生活质量来衡量，生活质量具有显着的因果中介效应。子量表心理健康（axb：-0.282）和应对（axb：-0.249）。所有其他潜在的干预变量都不显着。结论 我们的研究结果表明，生活质量（包括积极应对）作为预防抑郁症的改变机制具有相关作用。然而，还需要更多的研究来扩展和具体化我们对数字抑郁症预防的经验支持过程的知识。（PsycInfo 数据库记录 (c) 2023 APA，保留所有权利）。