1. Is duloxetine's effect on painful physical symptoms in depression an indirect result of improvement of depressive symptoms? Pooled analyses of three randomized controlled trials
- Author
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Shinji Fujikoshi, Michael H. Ossipov, Madelaine M. Wohlreich, Eiji Harada, Jumpei Funai, Nakao Iwata, and Hirofumi Tokuoka
- Subjects
medicine.medical_specialty ,education ,Pain ,Duloxetine Hydrochloride ,Placebo ,law.invention ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Randomized controlled trial ,Double-Blind Method ,law ,Rating scale ,Internal medicine ,medicine ,Duloxetine ,Humans ,030212 general & internal medicine ,Path analysis ,health care economics and organizations ,Pain Measurement ,Randomized Controlled Trials as Topic ,Analgesics ,Depressive Disorder, Major ,business.industry ,Depression ,medicine.disease ,Indirect effect ,Antidepressive Agents ,Anesthesiology and Pain Medicine ,Treatment Outcome ,Neurology ,chemistry ,Meta-analysis ,Physical therapy ,Major depressive disorder ,Neurology (clinical) ,business ,030217 neurology & neurosurgery ,Research Paper - Abstract
Path analysis segregates duloxetine's direct and indirect effects on pain and depression. The direct and indirect effects on depressive symptoms are the inverse of pain effects., In treating Major Depressive Disorder with associated painful physical symptoms (PPS), the effect of duloxetine on PPS has been shown to decompose into a direct effect on PPS and an indirect effect on PPS via depressive symptoms (DS) improvement. To evaluate the changes in relative contributions of the direct and indirect effects over time, we analyzed pooled data from 3 randomized double-blind studies comparing duloxetine 60 mg/d with placebo in patients with major depressive disorder and PPS. Changes from baseline in Montgomery–Åsberg Depression Rating Scale total and Brief Pain Inventory-Short Form average pain score were assessed over 8 weeks. Path analysis examined the (1) direct effect of treatment on PPS and/or indirect effect on PPS via DS improvement and (2) direct effect of treatment on DS and/or indirect effect on DS via PPS improvement. At week 1, the direct effect of duloxetine on PPS (75.3%) was greater than the indirect effect through DS improvement (24.7%) but became less (22.6%) than the indirect effect (77.4%) by week 8. Initially, the direct effect of duloxetine on PPS was markedly greater than its indirect effect, whereas later the indirect effect predominated. Conversely, at week 1, the direct effect of treatment on DS (46.4%) was less than the indirect effect (53.6%), and by week 8 it superseded (62.6%) the indirect effect (37.4%). Thus, duloxetine would relieve PPS directly in the initial phase and indirectly via improving DS in the later phase.
- Published
- 2015