Using clinical patient characteristics to predict treatment outcome of cognitive behavior therapies for individuals with medically unexplained symptoms: A systematic review and meta-analysis

Objective: For individuals with medically unexplained symptoms (MUS), cognitive behavioral therapy (CBT) is the best-evaluated treatment. This systematic review and meta-analyses identify clinical patient characteristics associated with the treatment outcome of CBT for MUS. Methods: A systematic literature search (PubMed, PsycInfo, Web of Science) resulted in 53 eligible studies; of these 32 studies could be included in meta-analyses. Pooled correlation coefficients between predictors and treatment outcome were calculated with a random-effects model. Moderator analyses were conducted to examine differences between subgroups of MUS and different levels of methodological study quality. Results: Meta-analyses demonstrated that individuals with higher symptom intensity (r = 0.38; p < 0.001), lower physical functioning (r = -0.29; p < 0.001), lower emotional and social functioning (r = -0.37; p < 0.001), more potential symptom-related incentives (r = -0.15; p = 0.001), or longer symptom duration (r = 0.10; p = 0.033) at the beginning of treatment reported less change of symptom severity until the end of therapy or higher end-of treatment symptom severity. The pooled effect sizes did not differ between certain subgroups of MUS or between different levels of methodological quality. Conclusion: Our findings indicated that clinical characteristics of MUS patients are associated with treatment outcome of CBT. We discuss how the results can be used to optimize and personalize future treatments for MUS.